Journal articles: 'Antenna diversity'

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Wang, Jianquan, Zhaobiao Lv, and Xinzhong Li. "Analysis of MIMO Diversity Improvement Using Circular Polarized Antenna." International Journal of Antennas and Propagation 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/570923.

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MIMO (Multiple Input Multiple Output) technique is one of the important means to enhance the system capacity. Diversity gain could be acquired by using traditional ±45° dual-polarized antenna, but in the scenario where multipath scattering is not strong, power-unbalance in two polarizations caused by polarization mismatching between transmitting and receiving antennas will reduce diversity gain. This problem can be effectively solved by using circular polarized antennas. In this paper, through theory analysis and test, the improvement of MIMO diversity gain using circular polarization antenna is analyzed.

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Ramadan, A. H., J. Costantine, Y. Tawk, C. G. Christodoulou, and K. Y. Kabalan. "Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications." International Journal of Antennas and Propagation 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/638627.

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Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR-) based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein.

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Daghari, Marwa, Chaker Essid, and Hedi Sakli. "Muli-UWB Antenna System Design for 5G Wireless Applications with Diversity." Wireless Communications and Mobile Computing 2021 (June 8, 2021): 1–18. http://dx.doi.org/10.1155/2021/9966581.

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In this paper, we propose a compact Multiple Input Multiple Output (MIMO) antenna system with high isolation for wireless applications in 5G connected devices. This MIMO antenna system with the size of 92 × 88 m m 2 consists of two elliptical antennas symmetrically arranged next to each other. Two decoupling methods which are neutralization and Defected Ground Structure (DGS) are applied to ensure diversity of the proposed MIMO antenna. The single and MIMO antennas are simulated and analyzed then fabricated and measured. A good agreement between measurements and simulations is obtained. These configurations, dedicated to covering the 3.4 GHz band -3.8 GHz, have shown very satisfactory performances more than -30 dB in terms of reduction of mutual coupling between the antennas constituting our system. MIMO diversity parameters, such as Envelope Correlation (ECC), Diversity Gain (DG), and total efficiency, are also studied for each proposed MIMO system. Thus, results demonstrate that our two proposed antenna configurations are very suitable for 5G MIMO applications.

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Senega, Simon, Ali Nassar, and Stefan Lindenmeier. "Automotive antenna diversity system for satellite radio with high phase accuracy in low SNR-scenarios." International Journal of Microwave and Wireless Technologies 10, no. 5-6 (June 2018): 578–86. http://dx.doi.org/10.1017/s1759078718000296.

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AbstractFor a fast scan-phase satellite radio antenna diversity system a noise correction method is presented for a significant improvement of audio availability at low signal-to-noise ratio (SNR) conditions. An error analysis of the level and phase detection within the diversity system in the presence of noise leads to a correction method based on a priori knowledge of the system's noise floor. This method is described and applied in a hardware example of a satellite digital audio radio services antenna diversity circuit for fast fading conditions. Test drives, which have been performed in real fading scenarios, are described and results are analyzed statistically. Simulations of the scan-phase antenna diversity system show higher signal amplitudes and availabilities. Measurement results of dislocated antennas as well as of a diversity antenna set on a single mounting position are presented. A comparison of a diversity system with noise correction, the same system without noise correction, and a single antenna system with each other is performed. Using this new method in fast multipath fading driving scenarios underneath dense foliage with a low SNR of the antenna signals, a reduction in audio mute time by one order of magnitude compared with single antenna systems is achieved with the diversity system.

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Chaudhary, Prashant, Ashwani Kumar, and B. K. Kanaujia. "A low-profile wideband circularly polarized MIMO antenna with pattern and polarization diversity." International Journal of Microwave and Wireless Technologies 12, no. 4 (October 14, 2019): 316–22. http://dx.doi.org/10.1017/s175907871900134x.

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AbstractThe present work describes a unique planar low-profile wideband circularly polarized Multiple-Input and Multiple-Output (MIMO) antenna operating in the X-band, with pattern and polarization diversity over the entire axial-ratio bandwidth (ARBW). The design is unique in the sense that a simple grounded stub introduced between two linearly polarized monopole antennas has been used to realize wideband circular polarization, pattern diversity, and high isolation between antennas. The ARBW of the MIMO antenna is 2.45 GHz (8.11–10.56) 3 dB and its impedance matching bandwidth is 3.52 GHz (8.07–11.59). The isolation is better than 20 dB. The antenna can be easily adapted to operate other frequency bands by simple frequency scaling. It has been fabricated on an FR-4 substrate and its performance has been compared against several existing available antennas.

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Ojaroudi Parchin, Naser, Haleh Jahanbakhsh Basherlou, Yasir I. A. Al-Yasir, Ahmed M. Abdulkhaleq, Mohammad Patwary, and Raed A. Abd-Alhameed. "A New CPW-Fed Diversity Antenna for MIMO 5G Smartphones." Electronics 9, no. 2 (February 4, 2020): 261. http://dx.doi.org/10.3390/electronics9020261.

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In this study, a new coplanar waveguide (CPW)-fed diversity antenna design is introduced for multiple-input–multiple-output (MIMO) smartphone applications. The diversity antenna is composed of a double-fed CPW-fed antenna with a pair of modified T-ring radiators. The antenna is designed to cover the frequency spectrum of commercial sub-6 GHz 5G communication (3.4–3.8 and 3.8–4.2 GHz). It also provides high isolation, better than −16 dB, without an additional decoupling structure. It offers good potential to be deployed in future smartphones. Therefore, the characteristics and performance of an 8-port 5G smartphone antenna were investigated using four pairs of the proposed diversity antennas. Due to the compact size and also the placement of the elements, the presented CPW-fed smartphone antenna array design occupies a very small part of the smartphone board. Its operation band spans from 3.4 to 4.4 GHz. The simulated results agree well with measured results, and the performance of the smartphone antenna design in the presence of a user is given in this paper as well. The proposed MIMO design provides not only sufficient radiation coverage supporting different sides of the mainboard but also polarization diversity.

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Klemp, O., and H. Eul. "Radiation Pattern Analysis of Antenna Systems for MIMO and Diversity Configurations." Advances in Radio Science 3 (May 12, 2005): 157–65. http://dx.doi.org/10.5194/ars-3-157-2005.

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Abstract. Multiple-input multiple-output (MIMO) antenna systems and antenna configurations for wideband multimode diversity rank among the emerging key technologies in next generation wireless communication systems. The analysis of such transmission systems usually neglects the influences of real antenna radiation characteristics as well as the influences of mutual coupling in a multielement antenna arrangement. Nevertheless, to achieve a detailed description of diversity gain and channel capacity by using several transmit- and receive antennas in a wireless link, it is essential to take all those effects into account. The expansion of the radiation fields in terms of spherical eigenmodes allows an analytical description of the antenna radiation characteristics and accounts for all the coupling effects in multielement antenna configurations. Therefore the radiation pattern analysis by spherical eigenmode expansion provides an efficient alternative to establish an analytical approach in the calculation of envelope correlation or channel capacity.

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Gnanaharan, I., and R. Anbazhagan. "Review on the Design of the Isolation Techniques for UWB-MIMO Antennas." Advanced Electromagnetics 7, no. 4 (August 31, 2018): 46–70. http://dx.doi.org/10.7716/aem.v7i4.743.

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Ultra wide band - Multiple Input Multiple Output antenna technology provides higher data rates and the combination of the ultra wide band (UWB) and the multiple input multiple output (MIMO) technologies provides a solution for the demand of still higher data rates i.e. in excess of 3 Gb/sec in the future. As the antenna technologies are improving, the size of the MIMO antenna is growing smaller and smaller. Placing the antenna elements in such close proximity increases the coupling between them. Various isolation techniques have to be introduced between the antenna elements to decrease the coupling and to improve the isolation. A study of the various isolation enhancement techniques have been made in this review. It analyses the various isolation enhancement methods such as using orthogonal polarization, parasitic elements, varied decoupling structures, defected ground structures (DGS), neutralization line (NL) and finally by using metamaterials. Metamaterials is a technology to perk up the isolation between the antenna elements. Split ring resonator (SRR) behaves as a metamaterial and it is used as an isolation mechanism in this study. The antennas are simulated and the results are compared. The method using parasitic elements gives the highest isolation of 35 dB and it is 5 dB better than the methods using orthogonal polarization and using the decoupling structure. The performance of all the antennas satisfies the conditions for minimum isolation. The envelope correlation coefficient is nearly zero in all the antennas and it implies good diversity performance. The diversity gain is also calculated for the various antennas and it satisfies good diversity performance. The bandwidth of the antennas is in the UWB frequency range and they have a fractional bandwidth above the required value of 1.09. The capacity loss for all the antennas is very low and the antennas using defected ground structure and the decoupling structure gives very low capacity loss.

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Mora-Andreu, Miguel, and David A. Sánchez-Hernández. "Novel Base Station MIMO Antennas with Enhanced Spectral Efficiencies Using Angular Reuse." International Journal of Antennas and Propagation 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/150301.

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The true polarization diversity (TPD) technique is combined with the spatial diversity technique in novel MIMO antenna array geometries with a large number of elements. The use of a large number of elements requires some angular reuse within the array for polarization diversity. With designs compatible with existing base station antenna array configurations, the novel geometries with combining diversity schemes are shown to be able to achieve near the maximum spectral efficiencies. True polarization diversity (TPD) schemes are found to be an excellent complement to more conventional spatial diversity schemes for obtaining optimum MIMO array performance in base station antennas.

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Wang, Chaowei, Weidong Wang, Cheng Wang, Shuai Wang, and Yang Yu. "A Fast Adaptive Receive Antenna Selection Method in MIMO System." International Journal of Antennas and Propagation 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/175783.

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Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO) systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

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El Hadri, Doae, Alia Zakriti, Asmaa Zugari, Mohssine El Ouahabi, and Jamal El Aoufi. "High Isolation and Ideal Correlation Using Spatial Diversity in a Compact MIMO Antenna for Fifth-Generation Applications." International Journal of Antennas and Propagation 2020 (July 24, 2020): 1–10. http://dx.doi.org/10.1155/2020/2740920.

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This paper presents a compact Multiple Input Multiple Output antenna with high isolation and low envelope correlation (ECC) for fifth-generation applications using spatial diversity technique. The proposed MIMO antenna consists of two single antennas, each having size of 13 × 12.8 mm2, symmetrically arranged next to each other. The single and MIMO antennas are simulated and analyzed. To verify the simulated results, the prototype antennas were fabricated and measured. A good agreement between measurements and simulations is obtained. The proposed antenna covers the 28 GHz band (27.5–28.35 GHz) allocated by the FCC for 5G applications. Moreover, the isolation is more than 35 dB and the ECC is less than 0.0004 at the operating band, which means that the mutual coupling between the two elements is negligible. The MIMO parameters, such as diversity gain (DG), total active reflection coefficient (TARC), realized gain, and efficiency, are also studied. Thus, the results demonstrate that our antenna is suitable for 5G MIMO applications.

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Zeng, Qinghao, Yuan Yao, Shaohua Liu, Junsheng Yu, Peng Xie, and Xiaodong Chen. "Tetraband Small-Size Printed Strip MIMO Antenna for Mobile Handset Application." International Journal of Antennas and Propagation 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/320582.

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A compact printed multiple-input multiple-output (MIMO) antenna for tetraband (GSM900/1800/1900/UMTS) mobile handset application is presented. The proposed MIMO antenna, which consists of two coupled-fed loop antennas with symmetrical configuration, was printed on a 120 * 60 * 0.8 mm3Fr-4 substrate of relative permittivity of 4.4, loss tangent 0.02. Each element antenna requires only a small area of 22.5 * 25 mm2on the circuit board. The edge-to-edge spacing between the two elements is only0.03λ0of 920 MHz. A slot and a dual-inverted-L-shaped ground branch were added in the ground plane to decrease the mature coupling between the antenna elements. The measured isolation of the proposed antenna is better than 15 dB among the four operating frequency bands. The simulated 3D radiation patterns at 900 MHz and 1900 MHz of both antenna elements show that two loop antennas in general cover complementary space regions with good diversity performance. Detailed antenna impedance matching performance comparisons were done to evaluate the benefit of using different decoupling technology. The envelop correlation coefficient is calculated to represent the diversity performance of the MIMO antenna.

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Ojaroudi Parchin, Naser, Haleh Jahanbakhsh Basherlou, Yasir I. A. Al-Yasir, Ahmed M. Abdulkhaleq, and Raed A. Abd-Alhameed. "Ultra-Wideband Diversity MIMO Antenna System for Future Mobile Handsets." Sensors 20, no. 8 (April 22, 2020): 2371. http://dx.doi.org/10.3390/s20082371.

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A new ultra-wideband (UWB) multiple-input/multiple-output (MIMO) antenna system is proposed for future smartphones. The structure of the design comprises four identical pairs of compact microstrip-fed slot antennas with polarization diversity function that are placed symmetrically at different edge corners of the smartphone mainboard. Each antenna pair consists of an open-ended circular-ring slot radiator fed by two independently semi-arc-shaped microstrip-feeding lines exhibiting the polarization diversity characteristic. Therefore, in total, the proposed smartphone antenna design contains four horizontally-polarized and four vertically-polarized elements. The characteristics of the single-element dual-polarized UWB antenna and the proposed UWB-MIMO smartphone antenna are examined while using both experimental and simulated results. An impedance bandwidth of 2.5–10.2 GHz with 121% fractional bandwidth (FBW) is achieved for each element. However, for S11 ≤ −6 dB, this value is more than 130% (2.2–11 GHz). The proposed UWB-MIMO smartphone antenna system offers good isolation, dual-polarized function, full radiation coverage, and sufficient efficiency. Besides, the calculated diversity performances of the design in terms of the envelope correlation coefficient (ECC) and total active reflection coefficient (TARC) are very low over the entire operating band.

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Yu, Bunggil, Chang Won Jung, Haechun Lee, Myun-Joo Park, Byeongkwan Kim, Hyunho Wi, Yonggyu Choi, Deokyun Kim, and Byungje Lee. "Closely Mounted Compact Wideband Diversity Antenna for Mobile Phone Applications." International Journal of Antennas and Propagation 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/798046.

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Here a compact wideband diversity antenna covering the PCS/UMTS/WiMAX bands with high isolation and low enveloped correlation coefficient (ECC) is proposed. To widen the bandwidth, the proposed antenna uses a structure with a gap-coupled feed and an inductively shorted line that has capacitive compensation between the radiator and the ground plane. Also, a suspended line with a parasitic element is used to enhance the isolation between the two antennas.

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Mouffok, L., A. C. Lepage, J. Sarrazin, and X. Begaud. "A compact dual-band dual-port diversity antenna for LTE." Advanced Electromagnetics 1, no. 1 (July 9, 2012): 52. http://dx.doi.org/10.7716/aem.v1i1.42.

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The design of a compact dual-band dual-port antenna system is presented. It operates in two frequency bands, 790-862 MHz and 2500-2690 MHz, thereby making it suitable for Long Term Evolution (LTE) handheld devices. The proposed system is composed of two orthogonal inverted-F antennas (IFA) to perform diversity in mobile terminals. A good agreement is observed between simulated and experimental results. The high antenna diversity capability of the proposed system is highlighted with the calculation of envelope correlation coefficient, mean effective and diversity gains for different environment scenarii.

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Manohar, Murli, Rakhesh Singh Kshetrimayum, and Anup Kumar Gogoi. "Low profile dual band-stop super wideband printed monopole antenna with polarization diversity." International Journal of Microwave and Wireless Technologies 11, no. 7 (March 5, 2019): 694–702. http://dx.doi.org/10.1017/s1759078719000175.

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AbstractA low profile super-wideband polarization diversity printed monopole antenna with dual band-notched characteristics is presented the first time. The designed antenna comprises two arched shaped radiating elements with two triangular tapered microstrip feed lines (TTMFL) and two arched shaped partial ground planes, which covers an enormously wide impedance bandwidth (BW) from 1.2 to 25 GHz (ratio BW of 20.8:3) for reflection coefficient |S11| < −10 dB. To ensure the high port isolation (better than − 30 dB) between two feeding ports over the whole bands, two analogous antennas have been kept perpendicular to each other at a distance of 1 mm. In addition, the dual band-notched performance in wireless local area network (5–6 GHz) and X-band (7.2–8.5 GHz) is generated by employing a pair of open-circuited stubs (L-shaped stub and horizontal stub) to the TTMFL. Envelop correlation coefficient has been computed to study the polarization diversity performance. Finally, the proposed antenna was fabricated and tested successfully. Measured results indicate that the proposed antenna is an appropriate candidate for the polarization diversity applications. The proposed antenna has a compact size of 40 × 70 × 0.787 mm3, high isolation, and occupies a small space compared with the existing antennas.

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Cheng, Chunxia, and Liyan Luo. "Mutual Coupling Reduction Using Improved Dual-Layer Mushroom and E-Shaped Stub." International Journal of Antennas and Propagation 2021 (February 18, 2021): 1–9. http://dx.doi.org/10.1155/2021/8862570.

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The improved dual-layer mushroom (IDLM) and back-to-back E-shaped stubs for mutual coupling reduction between microstrip patch antennas are presented in this paper. The IDLM unit consists of one upper layer complementary split-ring resonator lattice and four lower layer lattices, whose centers are connected to the ground by a pin. The decoupling structure can prevent the surface current from one antenna port to another, so as to improve the isolation between the antennas. The proposed antenna works in the open wireless communication band of 2.45 GHz. Using the proposed decoupling structure, a low mutual coupling level ranging from −27 to −40 dB is obtained when the center distance of the adjacent patches is 0.5λ0. The total size of the decoupling antenna is 99 × 41 × 2.4 mm3 with a frequency range of 2.42–2.48 GHz for S11 < −10 dB. The proposed decoupling structure can also improve the average gain and efficiency of the antenna by 0.1 dB and 5%, respectively. The antenna is studied from the aspects of isolation, return loss, current and electric field distribution, radiation pattern, and diversity performance. The designed decoupling antenna is fabricated and measured. The pattern, isolation, and return loss of the tested results show good consistence with the simulation results. The diversity gain and envelop correlation coefficient of the diversity performance show that the designed antenna can be used in MIMO or Rx/Tx systems.

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Zhao, Hui, Fushun Zhang, Chunyang Wang, and Jiangang Liang. "A Compact UWB Diversity Antenna." International Journal of Antennas and Propagation 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/805853.

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A compact printed ultrawideband (UWB) diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

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Sun, Xiao Jin, and Zhi Wen Hu. "Research on Wireless Communication Technology Based on Cooperative Diversity." Applied Mechanics and Materials 416-417 (September 2013): 1561–64. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.1561.

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Cooperative diversity technique refers to that in the context of multi-users, several single antenna terminals create a virtual multi-antenna system to realize the dispatch and diversity of the periodic line by means of share each others antenna. The remarkable strong point of the cooperative diversity technique is that it can reduce the transmission power of the system, improve its handing capacity and effectively decrease its error rate. This paper is going to analyze the application of the cooperative diversity technique on the wireless communication technology and present the main problems of the cooperative diversify technique by introducing the related conceptions of the cooperative diversity technique.

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Osman, Mohamed Nasrun, Mohamad Kamal A. Rahim, Mohamad Rijal Hamid, Mohd Fairus Mohd Yusoff, Mohamad Zoinol Abidin A. Aziz, Muzammil Jusoh, Muhammad Azfar Abdullah, and Nursaidah Muhamad Nadzir. "Indoor Channel Capacity Measurement of 2 x 2 MIMO Polarization Diversity Antenna." Indonesian Journal of Electrical Engineering and Computer Science 10, no. 3 (June 1, 2018): 1196. http://dx.doi.org/10.11591/ijeecs.v10.i3.pp1196-1202.

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<span>This paper presents the channel capacity investigation and the polarization reconfigurable antenna analysis for MIMO system in an indoor scenario. A single and dual-port polarization reconfigurable antenna is used at the receiver end to study the effect of polarization diversity configurations towards the achievable performance of the channel capacity. The polarization reconfigurable antennas are developed through two techniques, which are slits perturbation for single-port and feeding network modification for dual-port. The benefits offered by the designed antennas are investigated when being used as a receiver in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. The results show the proposed antennas are suitable to be adopted and highly potential to improve the channel capacity of the MIMO systems.</span>

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Gao, Yue, Shihua Wang, Oluyemi Falade, Xiadong Chen, Clive Parini, and Laurie Cuthbert. "Mutual Coupling Effects on Pattern Diversity Antennas for MIMO Femtocells." International Journal of Antennas and Propagation 2010 (2010): 1–8. http://dx.doi.org/10.1155/2010/756848.

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Diversity antennas play an important role in wireless communications. However, mutual coupling between multiple ports of a diversity antenna has significant effects on wireless radio links and channel capacity. In this paper, dual-port pattern diversity antennas for femtocell applications are proposed to cover GSM1800, UMTS, and WLAN frequency bands. The channel capacities of the proposed antennas and two ideal dipoles with different mutual coupling levels are investigated in an indoor environment. The relation between mutual coupling and channel capacity is observed through investigations of these antennas.

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See, Terence S. P., and Zhi Ning Chen. "An Ultrawideband Diversity Antenna." IEEE Transactions on Antennas and Propagation 57, no. 6 (June 2009): 1597–605. http://dx.doi.org/10.1109/tap.2009.2019908.

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Zhang, You Yan, and Shu Yue Hong. "A Novel Transmit Diversity Technique for MIMO System." Advanced Materials Research 468-471 (February 2012): 355–59. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.355.

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The antenna diversity based on log-likelihood ratio (LLR) is better than that based on signal-to-noise ratio (SNR) in bit error rate performance for MIMO systems. Thus in this paper, we present a novel transmit antenna selection scheme based on bit log-likelihood ratio when the Alamouti code is employed .Then the BER expressions of application based on Bit-LLR (BLLR) for MPSK and MQAM modulation with Gray code are derived. The simulation results show that the new scheme based on BLLR is superior to SNR. With the increase of the transmit antennas, the performance of system is improved significantly. Furthermore, the diversity order is the same as that of the full complexity systems.

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Dehghanian, V., J. Nielsen, and G. Lachapelle. "Diversity Gain through Antenna Blocking." International Journal of Antennas and Propagation 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/735080.

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As part of the typical usage mode, interaction between a handheld receiver antenna and the operator's RF absorbing body and nearby objects is known to generate variability in antenna radiation characteristics through blocking and pattern changes. It is counterintuitive that random variations in blocking can result in diversity gain of practical applicability. This diversity gain is quantified from a theoretical and experimental perspective. Measurements carried out at 1947.5 MHz verify the theoretical predictions, and a diversity gain of 3.1 dB was measured through antenna blocking and based on the utilized measurement setup. The diversity gain can be exploited to enhance signal detectability of handheld receivers based on a single antenna in indoor multipath environments.

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Punna, Bharghava, and Pachiyaannan Muthusamy. "PRINTED MIMO/DIVERSITY ANTENNA WITH POLARIZATION DIVERSITY." Progress In Electromagnetics Research Letters 99 (2021): 25–33. http://dx.doi.org/10.2528/pierl21051901.

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Hampel, S. K., O. Schmitz, and I. Rolfes. "Sievenpiper HIS and its influence on antenna correlation." Advances in Radio Science 6 (May 26, 2008): 39–44. http://dx.doi.org/10.5194/ars-6-39-2008.

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Abstract. \\label{sec:abstract} This paper deals with the influence of artificial magnetic conductors (AMC), so-called Sievenpiper High Impedance Surfaces (HIS), on the MIMO and Diversity performance of a planar linear-polarized 2×2 dipole array in the ISM-band at 2.45 GHz. The characteristic performance criteria such as envelope correlation coefficient, spectral efficiency, Mean Effective Gain (MEG) and Diversity gain of a coupled 2×2 dipole array are investigated. By means of full-wave electromagnetic analysis as well as Monte-Carlo simulations applying statistical channel models the characteristic antenna pattern just as the MIMO and Diversity analysis is performed, respectively. The obtained results show that the application of Sievenpiper High Impedance Surfaces to planar antenna arrays enables good MIMO and Diversity performance compared to ideal configurations in free-space while offering the design of low profile antennas with simultaneously enhanced characteristics.

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Pochernyaev, V. N., N. M. Syvkova, and V. S. Povkhlib. "SPATIAL DIVERSITY SIGNAL TRANSMISSION IN DIGITAL TROPOSCATTER STATIONS." Proceedings of the O.S. Popov ОNAT 1, no. 2 (December 31, 2020): 92–99. http://dx.doi.org/10.33243/2518-7139-2020-1-2-92-99.

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The article examines the possibility of increasing the normalized throughput of digital troposcatter stations on the way of using space-separated signal transmission. Shown is a block diagram of the transmitting path of a digital troposcatter station with space-separated signal transmission. Methods of separation at the reception of signals acting at the input of the space-time coding device of the transmission path of the microwave digital troposcatter station are analyzed. Three methods of signal addition are considered in detail: linear addition; auto selection; optimal (quasi-optimal) addition. Various variants of addition are analyzed: before the demodulator and after the demodulator. The calculation of the normalized channel capacity as a function of the signal-to-noise ratio for the case of two transmitting antennas with known and unknown channel matrices is carried out. It was found that with two transmitting antennas and an unknown channel matrix, the normalized bandwidth does not differ from the case of using one transmitting antenna. The effect of cross-polarization isolation on the normalized channel capacity is analyzed, when one transmitting antenna emits signals of horizontal polarization, and the second transmitting antenna emits signals of vertical polarization. The values of the error probability are obtained for spatially-separated signal transmission to two transmitting antennas for two laws of distribution of a random variable - Rayleigh and Rice. The Rice distribution law of a random variable, the error probability is expressed through the modified zero-order Bessel function. The calculated data are shown in the table. The calculation was carried out in two frequency ranges allowed for the use of troposcatter communication facilities and for a channel without fading and for a channel with intersymbol interference.

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Sulakshana, Chilukuri, and Lokam Anjaneyulu. "Reconfigurable antennas with frequency, polarization, and pattern diversities for multi-radio wireless applications." International Journal of Microwave and Wireless Technologies 9, no. 1 (June 4, 2015): 121–32. http://dx.doi.org/10.1017/s1759078715000926.

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This paper presents different reconfigurable antennas with frequency, polarization, and pattern diversities. All the antennas have a very simple, novel, and compact structures, which are used for different wireless communication applications. These antennas employ switching for obtaining different reconfigurations. At first, an E-shaped antenna is designed for multi-band frequency reconfigurability. Second, circular and rectangular-shaped patch antennas are designed for achieving diversity in polarization. At last, a pattern reconfigurable antenna is designed with multiport excitation. These antenna performances are analyzed using various parameters such as return loss, radiation pattern, voltage standing wave ratio (VSWR), and gain. The prototypes of the antennas are fabricated and measured results along with simulated ones are presented. Both the results are in good agreement.

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Moradikordalivand, Alishir, Chee Yen Leow, Tharek Abd Rahman, Sepideh Ebrahimi, and Tien Han Chua. "Wideband MIMO antenna system with dual polarization for WiFi and LTE applications." International Journal of Microwave and Wireless Technologies 8, no. 3 (March 4, 2015): 643–50. http://dx.doi.org/10.1017/s175907871500032x.

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In this paper a wideband multi-input multi-output (MIMO) antenna system for WiFi-LTE wireless access point (WAP) application is proposed. The MIMO antenna system consists of two common element microstrip-fed monopole antennas with dual polarization. Physically closed integration of MIMO antenna elements requires a special technique to increase the isolation between the antennas. A novel structure of parasitic element is introduced to improve the isolation between the antennas. The proposed MIMO antenna system is simulated and optimized using CST Microwave Studio. The designed antenna system is fabricated and measured to verify the simulation results. Reflection coefficient of less than −10 dB and isolation more than 15 dB are achieved in the operating frequency range of 2.3–2.9 GHz which covers WiFi 2.4 GHz and LTE 2.6 GHz bands. The proposed system also provides dual polarization with 10 dB polarization diversity gain and envelope correlation coefficient less than 0.15. Each individual antenna has a gain of 5.1 dB and 68% efficiency.

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Alwarafy, Abdulmalik, Ahmed Iyanda Sulyman, Abdulhameed Alsanie, Saleh A. Alshebeili, and Hatim M. Behairy. "Path-Loss Channel Models for Receiver Spatial Diversity Systems at 2.4 GHz." International Journal of Antennas and Propagation 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/6790504.

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This article proposes receiver spatial diversity propagation path-loss channel models based on real-field measurement campaigns that were conducted in a line-of-site (LOS) and non-LOS (NLOS) indoor laboratory environment at 2.4 GHz. We apply equal gain power combining (EGC), coherent and noncoherent techniques, on the received signal powers. Our empirical data is used to propose spatial diversity propagation path-loss channel models using the log-distance and the floating intercept path-loss models. The proposed models indicate logarithmic-like reduction in the path-loss values as the number of diversity antennas increases. In the proposed spatial diversity empirical path-loss models, the number of diversity antenna elements is directly accounted for, and it is shown that they can accurately estimate the path-loss for any generalized number of receiving antenna elements for a given measurement setup. In particular, the floating intercept-based diversity path-loss model is vital to the 3GPP and WINNER II standards since they are widely utilized in multi-antenna-based communication systems.

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31

Ozturk, Yusuf, and Vaibhav Nagarnaik. "Antenna diversity using single antenna in robot communication." Digital Signal Processing 20, no. 1 (January 2010): 155–65. http://dx.doi.org/10.1016/j.dsp.2009.03.010.

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Yang, Lingsheng, Peijie Wang, Biyu Cheng, and Jianping Fang. "Design of Hybrid Antenna System for User Terminal Applications." Frequenz 72, no. 9-10 (August 28, 2018): 407–14. http://dx.doi.org/10.1515/freq-2017-0197.

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Abstract An eight-element hybrid Smart antenna-MIMO system for user terminal application is proposed in this paper. The hybrid antenna system is based on an eight elements antenna array. When operate with respective feed ports, by using radiation pattern diversity, more than 15 dB isolation among antenna elements can be achieved. After designing the feed networks based on maximum power transmission optimization between the transmit and receive antennas, beam steering performance can be obtained, the eight elements work together as a smart antenna array. The hybrid system has both the advantages of MIMO and smart antenna, and is competitive for future wireless communication applications.

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Imran, Muhammad, and Haejoon Jung. "Outage Analysis of Distributed Antenna Systems in a Composite Fading Channel with Correlated Shadowing." Journal of Sensor and Actuator Networks 7, no. 3 (August 3, 2018): 32. http://dx.doi.org/10.3390/jsan7030032.

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Distributed antenna systems (DASs) are known to be effective to enhance coverage, spectral efficiency, and reliability in mobile communication systems. Because multiple antennas are physically separated in space, DASs benefit from both micro- and macro-diversity, which makes DASs significantly more robust compared to conventional co-located antenna systems in fading channels. However, when multiple antennas are not dispersed enough, there exists a certain degree of correlation in large-scale fading (shadowing), which degrades the macro-diversity gain. In practice, various measurements indicate a high degree of correlation of shadowing in DASs. However, most of the previous studies on DASs have not considered the correlated shadowing and its corresponding performance loss. Motivated by this limitation, we analyze the impact of the correlated shadowing to better evaluate DAS-based schemes with dual diversity transmitters. Assuming that shadowing correlation is an exponentially decreasing function of the inter-element separation, we derive the outage probability of DAS in composite Rayleigh-lognormal shadowing channels. Also, we present numerical and simulation results, which indicate there exists an optimal inter-separation between antennas that minimizes the outage rate to balance a trade-off between macro-diversity and path loss.

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Kumar, Raj, and Neha Pazare. "A CPW-fed stepped slot UWB antenna for MIMO/diversity applications." International Journal of Microwave and Wireless Technologies 9, no. 1 (June 1, 2015): 151–62. http://dx.doi.org/10.1017/s1759078715000975.

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An ultra-wideband (UWB) slot antenna for diversity applications is introduced. The overall structure of the antenna consists of two similar coplanar waveguide (CPW)-fed stepped rectangular slots placed in an orthogonal position. The slots are asymmetric with respect to their placement in the ground plane. The CPW feeds are double stepped and terminated on hexagonal patches for better impedance matching. A wide impedance bandwidth (measured) from 3 to 12 GHz with an isolation better than 15 dB is obtained with this antenna. To improve the isolation, the design is modified and an I-shaped slot strip is introduced between the two slot antennas. With this, the isolation is brought about 25 dB of most of the band, while the impedance bandwidth remains the same (2.8–12 GHz for port 1, measured and 2.9–12 GHz for port 2, measured). The far-field radiation patterns are also measured and a peak gain of about 5 dBi is obtained. Finally, the diversity parameters such as envelope correlation coefficient and capacity loss are calculated and found to have low values. The antenna is expected to be useful for UWB diversity applications with good isolation.

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Mir, Amna, Junsheng Yu, Xiaodong Chen, and Ishtiaq Ahmad. "Numerical study of terahertz circular polarized substrate lens dipole antennas for polarization sensitive detectors." International Journal of Microwave and Wireless Technologies 8, no. 3 (March 19, 2015): 623–31. http://dx.doi.org/10.1017/s1759078715000380.

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Wide band circular polarized (CP) antennas behind extended hemispherical lenses suitable for polarization sensitive THz detector and wireless communication have been designed and characterized using numerical simulation. Two novel, compact and CP dipole antennas are designed and studied for this purpose. CP property of planar antennas is achieved by geometrical modifications of antennas without any complicated feeding structure. Due to compact dimensions, wideband performance and CP behavior, these designs have applications in circular dichroism (CD) spectroscopy and terahertz detectors. This numerical study deals with polarization diversity with substrate lens, effect of off axis displacement on CP behavior of lens antenna which determines number of pixels for any application, far field patterns variation due to lens's internal reflection, directivity variation attributed to internal reflection and losses. Radiation efficiency variation of antenna by antenna dimensions is also studied carefully to design appropriate lens from application's point of view. Off axis performance of antenna on hemisphere lens is also studied and redesigning of antenna by some geometric modification has been carried out to improve far field patterns.

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Asif, Raees, Abdul Aziz, Muhammad Amjad, Majid Akhtar, Abuzar Baqir, and M. Nawaz Abbasi. "Analysis and Design of an Efficient and Novel MIMO Antenna for 5G Smart Phones Using FDTD and FEM." Applied Computational Electromagnetics Society 36, no. 3 (April 20, 2021): 266–72. http://dx.doi.org/10.47037/2020.aces.j.360306.

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A novel and compact antenna element is analyzed and designed to achieve an efficient 4x4 MIMO antenna for a mobile phone at 3.5 GHz band for 5G communication. FTDT and FEM techniques are used to analyze and compare modeling accuracy of the proposed MIMO antenna. It has achieved a minimum isolation of 19.7dB between two antennas with radiation efficiency of 86%. The improved isolation and efficiency for the proposed MIMO antenna has been achieved without any decoupling structure between antennas, instead larger separation between elements due to compact size of the proposed element facilitated to achieve good performance. Pattern diversity is also achieved by arranging adjacent asymmetric antennas in reverse direction with each other. The envelope correlation coefficient (ECC) is less than 0.002 and Channel Capacity loss (CCL) is also less than 0.4 bps/Hz in the whole frequency band (3.36-3.66 GHz), which is suitable for 5G MIMO systems.

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Zheng, Jianfeng, Yue Li, and Zhenghe Feng. "Impact of Mutual Coupling and Polarization of Antennas on BER Performances of Spatial Multiplexing MIMO Systems." International Journal of Antennas and Propagation 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/795205.

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This paper is aimed at studying the impacts of mutual coupling, matching networks, and polarization of antennas on performances of Multiple-Input Multiple-Output (MIMO) systems employing Spatial Multiplexing (SM). In particular, the uncoded average Bit Error Rate (BER) of MIMO systems is investigated. An accurate signal analysis framework based on circuit network parameters is presented to describe the transmit/receive characteristics of the matched/unmatched antenna array. The studied arrays consist of matched/unmatched compact copolarization and polarization diversity antenna array. Monte-Carlo numerical simulations are used to study the BER performances of the SM MIMO systems using maximum-likelihood and/or zero-forcing detection schemes. The simulation results demonstrate that the use of matching networks can improve the BER performance of SM MIMO systems significantly, and the BER performance deterioration due to antenna orientation randomness can be compensated by use of polarization diversity antenna arrays.

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Malviya, Leeladhar, Rajib Kumar Panigrahi, and M. V. Kartikeyan. "MIMO antennas with diversity and mutual coupling reduction techniques: a review." International Journal of Microwave and Wireless Technologies 9, no. 8 (May 9, 2017): 1763–80. http://dx.doi.org/10.1017/s1759078717000538.

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Multiple input multiple output (MIMO) antenna is at core of the presently available wireless technologies. The design of MIMO antennas over a limited space requires various approaches of mutual coupling reduction, otherwise gain, efficiency, diversity gain, and radiation patterns will be severely affected. Various techniques have been reported in literature to control this degrading factor and to improve the performance of the MIMO antennas. In this review paper, we have carried out an extensive thorough investigation of diversity and mutual coupling (correlation) reduction techniques in compact MIMO antennas.

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Karaboikis, M., V. Papamichael, C. Soras, and V. Makios. "A Multiband Diversity Antenna System for Compact Mobile/Wireless Devices: Modeling and Performance Evaluation." International Journal of Antennas and Propagation 2008 (2008): 1–7. http://dx.doi.org/10.1155/2008/782153.

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A novel compact multiband diversity antenna system appropriate for integration onto space-limited devices is presented. It comprises three pairs of printed fractal Minkowski and Koch monopole antennas which resonate in the 1.67–2, 2.3–2.56 and 4.55–5.55 GHz bands, respectively, supporting thus a large variety of wireless technologies for mobile and wireless local area networks (WLANs) applications. The operational characteristics of the antenna system were extracted by simulation using a method-of-moment- (MoM-) based electromagnetic field solver. The diversity performance in a uniform multipath environment under the maximal-ratio combining (MRC) scheme is also evaluated for the two extreme modes of operation, that is, when all three antenna pairs operate simultaneously (worst case) and when only one pair is active while the others being open-circuited (best case). The calculated effective diversity gain (EDG) for the worst/best case is 5.8/6.4, 5.8/7.2 and 7.1/7.5 dB for the 1.8, 2.4 and 5.2 GHz frequencies, respectively.

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40

Chu, Jessie, P. D. Si Dong, and Grace Panganiban. "Limb type-specific regulation of bric a brac contributes to morphological diversity." Development 129, no. 3 (February 1, 2002): 695–704. http://dx.doi.org/10.1242/dev.129.3.695.

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The insect antenna and leg are considered homologous structures, likely to have arisen via duplication and divergence from an ancestral limb. Consistent with this, the antenna and leg are derived from primordia with similar developmental potentials. Nonetheless, the adult structures differ in both form and function. In Drosophila, one conspicuous morphological difference is that the antenna has fewer distal segments than the leg. We propose that this is due in part to the variations in the regulation of bric a brac. bric a brac is required for joint formation, and loss of bric a brac function leads to fusion of distal antennal and leg segments, resulting in fewer total segments. Here, we address how bric a brac is regulated to generate the mature expression patterns of two concentric rings in the antenna versus four concentric rings in the leg. We find that bric a brac expression is activated early throughout most of the Distal-less domain in both antenna and leg and subsequently is restricted to the distal portion and into rings. Although bric a brac expression in the antenna and in all four tarsal rings of the leg requires Distal-less, only the proximal three tarsal rings are Spineless-dependent. Thus bric a brac is regulated differentially even within a single appendage type. The restriction of bric a brac expression to the distal portion of the Distal-less domain is a consequence of negative regulation by distinct sets of genes in different limb types. In the leg, the proximal boundary of bric a brac is established by the medial-patterning gene dachshund, but dachshund alone is insufficient to repress bric a brac, and the expression of the two genes overlaps. In the antenna, the proximal boundary of bric a brac is established by an antenna-specifying gene, homothorax, in conjunction with dachshund and spalt, and there is much less overlap between the bric a brac and the dachshund domains. Thus tissue-specific expression of other patterning genes that differentially repress bric a brac accounts for antenna-leg differences in bric a brac pattern. We propose that the limb type-specific variations in expression of bric a brac repressors contribute to morphological variations by controlling distal limb segment number.

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Lawrence, Nicholas P., Christophe Fumeaux, and Derek Abbott. "Planar Triorthogonal Diversity Slot Antenna." IEEE Transactions on Antennas and Propagation 65, no. 3 (March 2017): 1416–21. http://dx.doi.org/10.1109/tap.2016.2647719.

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Wee Kian Toh, Zhi Ning Chen, Xianming Qing, and T. See. "A Planar UWB Diversity Antenna." IEEE Transactions on Antennas and Propagation 57, no. 11 (November 2009): 3467–73. http://dx.doi.org/10.1109/tap.2009.2024131.

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43

Jardine, A. J., J. S. Thompson, S. McLaughlin, and P. M. Grant. "Dual antenna cooperative diversity techniques." IEE Proceedings - Communications 153, no. 4 (2006): 556. http://dx.doi.org/10.1049/ip-com:20050362.

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44

Vaughan, R. G., and J. B. Andersen. "Antenna diversity in mobile communications." IEEE Transactions on Vehicular Technology 36, no. 4 (November 1987): 149–72. http://dx.doi.org/10.1109/t-vt.1987.24115.

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Su, Saou-Wen, Jui-Hung Chou, and Tzuenn-Yih Wu. "Internal broadband diversity dipole antenna." Microwave and Optical Technology Letters 49, no. 4 (2007): 810–12. http://dx.doi.org/10.1002/mop.22287.

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Lempiäinen, J. J. A., K. I. Nikoskinen, and J. O. Juntunen. "Multistate phase diversity microcell antenna." Electronics Letters 33, no. 6 (1997): 438. http://dx.doi.org/10.1049/el:19970329.

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Zahra, Hijab, Wahaj Abbas Awan, Wael Abd Ellatif Ali, Niamat Hussain, Syed Muzahir Abbas, and Subhas Mukhopadhyay. "A 28 GHz Broadband Helical Inspired End-Fire Antenna and Its MIMO Configuration for 5G Pattern Diversity Applications." Electronics 10, no. 4 (February 7, 2021): 405. http://dx.doi.org/10.3390/electronics10040405.

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In this paper, an end-fire antenna for 28 GHz broadband communications is proposed with its multiple-input-multiple-output (MIMO) configuration for pattern diversity applications in 5G communication systems and the Internet of Things (IoT). The antenna comprises a simple geometrical structure inspired by a conventional planar helical antenna without utilizing any vias. The presented antenna is printed on both sides of a very thin high-frequency substrate (Rogers RO4003, εr = 3.38) with a thickness of 0.203 mm. Moreover, its MIMO configuration is characterized by reasonable gain, high isolation, good envelope correlation coefficient, broad bandwidth, and high diversity gain. To verify the performance of the proposed antenna, it was fabricated and verified by experimental measurements. Notably, the antenna offers a wide −10 dB measured impedance ranging from 26.25 GHz to 30.14 GHz, covering the frequency band allocated for 5G communication systems with a measured peak gain of 5.83 dB. Furthermore, a performance comparison with the state-of-the-art mm-wave end-fire antennas in terms of operational bandwidth, electrical size, and various MIMO performance parameters shows the worth of the proposed work.

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Chi, Yu-Jen, and Fu-Chiarng Chen. "A novel quadri-polarization-agile microstrip antenna with polarization synthesizing feeding network." International Journal of Microwave and Wireless Technologies 8, no. 2 (March 26, 2015): 385–94. http://dx.doi.org/10.1017/s1759078715000227.

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This paper proposes planar antennas with quadri-polarization diversity using a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations (CP). A novel feeding network with four input ports and four output ports is presented, allowing antenna polarization diversity by selecting different input ports, which can generate right-handed CP, left-handed CP, horizontal linear polarization, and vertical linear polarization. The first design uses two square patch resonators to synthesize the four polarizations; the second design comprises four circularly polarized patches to synthesize the four polarizations with an improved axial-ratio (the ratio of orthogonal components of an E-field) bandwidth. The proposed designs do not require for embedding PIN diodes and DC-biasing circuits, making them suitable for use in higher-frequency applications where using lump elements would be difficult. The novel antennas provide potential polarization diversity features which can be used for many applications. Details of the antenna design are shown, and the measurement and simulation results are also provided to validate the proposed concept.

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Arai, Hiroyuki, Hiroyuki Teramoto, and Masahiro Toki. "Planar four-direction antenna for antenna pattern diversity reception." Electronics and Communications in Japan (Part I: Communications) 74, no. 7 (July 1991): 98–106. http://dx.doi.org/10.1002/ecja.4410740710.

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Sanad, Mohamed, and Noha Hassan. "Novel Wideband MIMO Antennas That Can Cover the Whole LTE Spectrum in Handsets and Portable Computers." Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/694805.

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A dual resonant antenna configuration is developed for multistandard multifunction mobile handsets and portable computers. Only two wideband resonant antennas can cover most of the LTE spectrums in portable communication equipment. The bandwidth that can be covered by each antenna exceeds 70% without using any matching or tuning circuits, with efficiencies that reach 80%. Thus, a dual configuration of them is capable of covering up to 39 LTE (4G) bands besides the existing 2G and 3G bands.2×2MIMO configurations have been also developed for the two wideband antennas with a maximum isolation and a minimum correlation coefficient between the primary and the diversity antennas.

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Journal articles on the topic 'Antenna diversity'

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