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Yufeng Yu, Zhongxiang Shen e Sailing He. "Compact Omnidirectional Antenna of Circular Polarization". IEEE Antennas and Wireless Propagation Letters 11 (2012): 1466–69. http://dx.doi.org/10.1109/lawp.2012.2231392.
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Wei, Kun, Jian-Ying Li, Ling Wang e Zijian Xing. "A NEW OMNIDIRECTIONAL CIRCULAR POLARIZATION MICROSTIP ANTENNA". Progress In Electromagnetics Research Letters 53 (2015): 45–50. http://dx.doi.org/10.2528/pierl15030902.
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Wu, Junyan, Jiaao Yu e Qin Tao. "Design of a Missile-borne Conformal Microstrip Navigation Antenna". MATEC Web of Conferences 232 (2018): 04080. http://dx.doi.org/10.1051/matecconf/201823204080.
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A missile-borne conformal dual-fed circular polarized microstrip antenna array is designed and fabricated, which realized omnidirectional radiation in horizontal direction. Frequencies of the antenna include GPS L1 frequency (1.575GHz) and Beidou navigation system B1 frequency (1.562GHz). Based on the HFSS simulation, the influence of conformation is analyzed on S11, axial ratio and gain of antenna array. The size of microstrip patches is changed so that the influence of conformation on antenna can be reduced. The circular polarization performance and the circular polarization gain of the antenna are also improved. The antenna array prototype is fabricated and measured. The result shows that the S11 parameter of the antenna is less than -10dB in the 1.55~1.60GHz frequency band. At the GPS L1 frequency and the Beidou B1 frequency, the maximum of horizontal omnidirectional gain is 1.73dB, 1.25dB respectively. The out-of-roundness of the radiation pattern is less than 2.5dB. The antenna has a good horizontal omnidirectional circular polarization radiation performance.
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Zhang, Ke, Xiangjun Li, Lei Chen, Zengjun Liu e Yuchen Xie. "Impact Analysis of Orthogonal Circular-Polarized Interference on GNSS Spatial Anti-Jamming Array". Remote Sensing 16, n.º 23 (1 de dezembro de 2024): 4506. https://doi.org/10.3390/rs16234506.
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With the continuous advancement of electromagnetic countermeasures, new types of interference signals (e.g., multi-polarization suppression interference) pose a significant threat to conventional Global Navigation Satellite System (GNSS) services, even when the receiver employs a right-handed circularly polarized (RHCP) anti-jamming array. This paper proposes a receiving signal model for orthogonal circularly polarized (OCP) interference signals based on conventional arrays, following an analysis of the non-ideal characteristics of actual arrays. Furthermore, the mechanism by which OCP interference signals affect anti-jamming performance is examined. Power inversion (PI) and linear constrained minimum variance (LCMV) techniques, applied to both uniform linear arrays and central circular arrays, are utilized to verify the impact of these interference signals. Simulation and physical testing demonstrate that OCP interference significantly affects the interference subspace of the conventional RHCP array, potentially leading to a reduction in the anti-jamming performance of the receiver. To effectively suppress multi-polarization interference, anti-jamming GNSS receivers must either ensure the consistency of cross-polarization among the elements of the array or adopt polarization-sensitive arrays.
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Su, Changjiang, Yanqun Liu, Leilei Liu, Mei Yang, Hongxin Zhao e Xiaoxing Yin. "Experimental Evaluation of Multipath Mitigation in TDOA-Based Indoor Passive Localization System Using A Beam Steering Broadband Circular Polarization Antenna". Electronics 7, n.º 12 (1 de dezembro de 2018): 362. http://dx.doi.org/10.3390/electronics7120362.
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An experimental evaluation of multipath mitigation using a beam steering broadband circular polarization antenna (BSBCPA) in indoor passive localization system based on time differences of arrival (TDOA) is presented in this paper. The BSBCPA consists of a beam switch network, four identical hexagon patch elements and their respective feeding networks. By controlling the states of a radio frequency (RF) switch in the beam switch network, four steering circular polarization beams can be excited separately for azimuth omnidirectional coverage. Combining the spatial selectivity of steering beams and circular polarization in the BSBCPA, the positioning inaccuracy from indoor multipath propagation can be mitigated. In two different indoor environments with line of sight (LOS), complex multipath, when transmitting a 20 MHz bandwidth signal in WLAN, the 2D positioning mean error obtained is 0.7 m and 0.82 m, respectively. Compared with conventional omnidirectional linear polarization antenna (OLPA), the BSBCPA can at least improve positioning accuracy by 51%. The experimental results show that the proposed BSBCPA can significantly mitigate multipath propagation for TDOA-based indoor passive localization.
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Mulimbayan, Francis, e Manolo G. Mena. "Comparative Study of the Corrosion Behavior of Low-Nickel AISI 202 and Conventional AISI 304 Stainless Steels in Citric Acid Using Electrochemical Techniques". Applied Mechanics and Materials 835 (maio de 2016): 131–35. http://dx.doi.org/10.4028/www.scientific.net/amm.835.131.
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Stainless steel (SS) is one of the most commonly used metallic food contact materials. It may be classified based on its microstructure whether ferritic, austenitic, martensitic, duplex or precipitation hardened. Austenitic SS, among mentioned grades, has the largest contribution to market due to its numerous industrial and domestic applications. In this study, the corrosion behavior of AISI 202 SS – a cheaper grade of stainless steel, in three different solution temperatures of citric acid was investigated using different electrochemical techniques such as open-circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results were compared to that obtained from conventional AISI 304 SS. OCP, polarization and impedance measurements agreed that AISI 202 SS has comparable resistance to that of AISI 304 SS in citric acid at ambient temperature and at 50 °C. At 70 °C, results of OCP measurements suggest that AISI 304 SS exhibited greater performance as indicated by more positive OCP values in the designated solution. EIS results indicate that the two alloys have identical corrosion resistance even at 70 °C as indicated by their comparable polarization resistance (Rp). The corrosion mechanism in both alloys is charge-transfer controlled as indicated by depressed semi-circular appearance of the generated Nyquist plots. The values of corrosion current densities (icorr) extracted from polarization curves indicate that the initial corrosion rates were higher in AISI 304 than AISI 202 SS suggesting that formation of more protective film may have occurred on the former alloy.
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Wei, Qian, Jiaju Wu, Zhiwei Guo, Xiaotian Xu, Ke Xu, Yong Sun, Yunhui Li, Haitao Jiang e Hong Chen. "Photonic Bandgaps of One-Dimensional Photonic Crystals Containing Anisotropic Chiral Metamaterials". Photonics 9, n.º 6 (10 de junho de 2022): 411. http://dx.doi.org/10.3390/photonics9060411.
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Conventional photonic bandgaps (PBGs) for linear polarization waves strongly depend on the incident angle. Usually, PBGs will shift toward short wavelengths (i.e., blue-shifted gaps) as the incident angle increases, which limits their applications. In some practices, the manipulation of PBGs for circular polarization waves is also important. Here, the manipulation of PBGs for circular polarization waves is theoretically investigated. We propose one-dimensional photonic crystals (1DPCs) containing anisotropic chiral metamaterials which exhibit hyperbolic dispersion for left circular polarization (LCP) wave and elliptical dispersion for right circular polarization (RCP) wave. Based on the phase variation compensation effect between anisotropic chiral metamaterials and dielectrics, we can design arbitrary PBGs including zero-shifted and red-shifted PBGs for LCP wave. However, the PBGs remain blue-shifted for RCP wave. Therefore, we can design a high-efficiency wide-angle polarization selector based on the chiral PBGs. Our work extends the manipulation of PBGs for circular polarization waves, which has a broad range of potential applications, including omnidirectional reflection, splitting wave and enhancing photonic spin Hall effect.
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Zhou, Yun, Shaojun Fang, Hongmei Liu, Zhongbao Wang e Te Shao. "A Function Reconfigurable Antenna Based on Liquid Metal". Electronics 9, n.º 5 (24 de maio de 2020): 873. http://dx.doi.org/10.3390/electronics9050873.
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To meet the demands of maritime transportation on ships, including satellite positioning, wireless communication, and radio frequency identification (RFID) for cargo handling management, a function reconfigurable antenna based on liquid metal is proposed in this paper. The antenna is composed of 3-D-printed hollow cavities, a two-step impedance feeding sheet, and two feeding probes. The 3-D-printed hollow cavities contain a big hollow helix cavity, a hollow cone loaded cylinder cavity, four hollow cylinder cavities, and four small hollow helix cavities. By filling the liquid metal into different hollow cavities, reconfigurable functions are generated, including right-handed circular polarization (RHCP), omnidirectional linear polarization (O-LP), pattern reconfigurable circular polarization, and omnidirectional left-handed circular polarization (O-LHCP). To illustrate this, a prototype is fabricated using 3-D-printed photopolymer resin and etching technology. The measurement results agree well with the simulated ones in terms of return loss, radiation pattern, gain, and axial ratio (AR). For the five reconfigurable states, the measured relative bandwidths for |S11| < −10 dB are 44.7%, 41.7%, 30.4%, 28.1%, and 10.8%, respectively, which covers the bands of a global navigation satellite system (GNSS), wireless communication system, and RFID communication system. Attributing to the advantages of its compact structure, flexible conversion, and good performance, the proposed antenna is a good candidate for maritime transportation applications.
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Keshari, Jaishanker Prasad, Binod Kumar Kanaujia, Mukesh Kumar Khandelwal, Pritam Singh Bakariya e Ram Mohan Mehra. "Omnidirectional multi-band stacked microstrip patch antenna with wide impedance bandwidth and suppressed cross-polarization". International Journal of Microwave and Wireless Technologies 9, n.º 3 (24 de fevereiro de 2016): 629–38. http://dx.doi.org/10.1017/s1759078716000209.
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In this paper, triple-band stacked microstrip patch antennas (MPAs) are presented with wide impedance bandwidth and suppressed cross-polarization level. Triangular and circular shaped slots are embedded in the patch of antenna. Slot-loaded microstrip patches are fed with meandered microstrip line supported by a semi-ground plane structure. Triangular shaped slot-loaded MPA shows triple resonance at frequencies 2.2, 4.45, and 5.3 GHz having bandwidth of 45.9, 19.23, and 15.67%, respectively. Circular shaped slot-loaded MPA also shows triple resonance at frequencies 2.2, 4.42, and 5.38 GHz having bandwidth of 50.24, 33.21, and 13.43%, respectively. Using circular slot in place of triangular; bandwidth of the first and the second band is improved by 4.34 and 13.98%, respectively. Both the proposed antennas show an omnidirectional radiation pattern at all three resonance frequencies in the xz-plane with almost 0 dBi gain. Both the proposed antennas are fabricated on a FR-4 epoxy substrate and show a minimum level of cross-polarization radiations.
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Li, Weiwei, Kwok Wa Leung e Nan Yang. "Omnidirectional Dielectric Resonator Antenna With a Planar Feed for Circular Polarization Diversity Design". IEEE Transactions on Antennas and Propagation 66, n.º 3 (março de 2018): 1189–97. http://dx.doi.org/10.1109/tap.2018.2794323.
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Dangkham, Piyapong, Sitthichai Dentri, Chuwong Phongcharoenpanich e Prayoot Akkaraekthalin. "Circularly Polarized Omnidirectional Antenna with Dipole Core and Diagonally Adjoined Parasitic Braces for ISM Band Applications". International Journal of Antennas and Propagation 2019 (21 de agosto de 2019): 1–11. http://dx.doi.org/10.1155/2019/2463871.
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This research proposes a circularly polarized (CP) single-fed omnidirectional dipole antenna operable in 2.45 GHz frequency for the industrial, scientific, and medical (ISM) radio band applications. The proposed antenna consisted of bisectional dipole core, a pair of quarter-wave baluns, and four diagonally adjoined parasitic braces. The bisectional dipole core was utilized to improve the antenna gain and realize omnidirectional radiation pattern, and the quarter-wave baluns were to symmetrize the current on the bisectional core. The four parasitic braces collectively generated circular polarization. In the study, simulations were conducted using CST Microwave Studio and a prototype antenna fabricated. To validate, experiments were carried out, and simulation and experimental results compared. The finding revealed good agreement between the simulation and experimental results. Essentially, in addition to achieving an antenna gain of 2.07 dBic, the proposed CP single-fed omnidirectional antenna is suited to ISM frequency band applications.
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Sharma, Manish. "Design of multiband circularly/linearly polarized antenna for multiple wireless (WWAN/Bluetooth/WiMAX/WLAN/Downlink Satellite System)". International Journal of Microwave and Wireless Technologies 11, n.º 9 (24 de junho de 2019): 967–74. http://dx.doi.org/10.1017/s1759078719000692.
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AbstractIn this article, a multiband antenna for various wireless communications is proposed for WWAN, Bluetooth, WiMAX, WLAN, and Downlink satellite system. The antenna consists of a radiating patch and a rectangular ground plane with four L-shaped stubs which are embedded as side arms to obtain a resonating band for WWAN (1.9GHz), Bluetooth (2.4 GHz), WiMAX (2.5, 3.5, and 5.5 GHz), and WLAN (5.5 GHz) wireless systems and a C-shaped stub is etched on the radiating patch to obtain a higher WLAN band (2.4, 5.2, and 5.8 GHz) and a satellite downlink system (7.5 GHz). The proposed antenna exhibits circular polarization at WWAN band and linear polarization for remaining applications. Also, the proposed antenna exhibits an omnidirectional radiation pattern.
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Cheng, Jia, Tianyu Gao, Dongpeng Han e Changfei Zhou. "Dual-Band Shared-Aperture Antenna with Pattern and Polarization Diversity". Applied Sciences 15, n.º 2 (17 de janeiro de 2025): 878. https://doi.org/10.3390/app15020878.
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This paper proposes a dual-band co-aperture antenna, which covers 2.09–11.61 GHz (9.52 GHz, 138.9%) and 21.6–29.6 GHz (8 GHz, 31%). The overall size of the proposed antenna is 0.76 × 0.76 × 0.37 λ03, where λ0 is the free space wavelength of the lowest operating frequency of 2.09 GHz. By removing the internal metal of the monopole antenna and adding a Vivaldi antenna at the bottom of the bowl monopole antenna, dual-band radiation characteristics can be achieved. A medium polarization converter is used to achieve circular polarization and improve the broadside gain in the high-frequency band. The simulation results show that the antenna has a stable omnidirectional radiation pattern in the low-frequency band and a directional radiation pattern in the high-frequency band.
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Yang, Jiawei, Xi Li e Lin Yang. "A Novel Design of CPW Feed Planar Omnidirectional Circularly Polarized Antenna". International Journal of Antennas and Propagation 2021 (27 de março de 2021): 1–7. http://dx.doi.org/10.1155/2021/6695966.
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A novel planar omnidirectional circularly polarized (CP) antenna is presented. The omnidirectional circular polarization characteristics of the planar antenna are the result of the combined effect of a planar quasi-magnetic dipole (PQMD) and a printed electric dipole (PED) in this paper. The CP radiation pattern of the proposed antenna can be achieved by distributing appropriate current amplitude and phase to both elements, respectively. A power divider is used to adjust the amplitude and phase relationship between two basic components. In order to achieve a planar structure, coplanar waveguide (CPW) feed is adopted to feed the quasi-magnetic dipole for the first time. The overall electrical size of antenna is 1.61λ × 0.38λ. Finally, the correctness of our theoretical analysis is verified by processing and measuring this antenna. Through the analysis of the measurement results, we have obtained the following conclusions: the operating bandwidth of the proposed antenna obtained by measurement is from 5.67 to 5.86 GHz, in which the reflection coefficient is less than −10 dB and the axial ratio is less than 3 dB. Within the available bandwidth, the proposed antenna achieves omnidirectional radiation characteristics with a gain between 0.89 and 2.48 dBic.
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Voitovich, V. V., Yu V. Petrash, M. M. Belousov, E. M. Yungaitis, A. V. Ershov e N. I. Voitovich. "DIPOLE ANTENNA WITH CIRCULAR RADIATION PATTERN IN THE E-PLANE FOR VALIDATION THE INTEGRITY OF THE AIRCRAFT LANDING SYSTEMS INFORMATION". Journal of the Ural Federal District. Information security 20, n.º 4 (2020): 31–43. http://dx.doi.org/10.14529/secur200403.
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The paper presents the results of studies of an omnidirectional dipole antenna designed for installation on an unmanned aerial vehicle of the mini-UAV category. The antenna forms a cir-cular radiation pattern in the horizontal plane with horizontal polarization of the radiated field. Irregularity of the radiation pattern of the antenna under study in free space in the horizontal plane is ±0.2 dB. The antenna contains a minimum number of elements of the feeder path. It has convenient for practical implementation design
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Bou-El-Harmel, Abdelhamid, Ali Benbassou, Jamal Belkadid e Nadia Mechatte. "Effect of Quasi-Isotropic Antenna Orientation on Indoor Multipath Propagation Characteristics in RSN Applications". International Journal of Antennas and Propagation 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/2686123.
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In the RFID sensor networks (RSN), the orientations of the antennas used in the network nodes have a significant influence on the propagation characteristics. In this article, we investigated the effects of the two antennas’ orientation of different radiation and polarization on the multipath propagation characteristics. This study is evaluated in a typical indoor environment by computer simulations based on the three-dimensional (3D) ray-tracing method. This method is based on geometric optics and uniform diffraction theory and also it offers significant advantages in terms of accurate and comprehensive prediction of propagation characterization. The simulations have been performed at frequency 915 MHz and the propagation characteristics are compared in terms of received power level (Pr) and Root-Mean-Square (RMS) delay spread for a quasi-isotropic 3D cubic antenna with circular polarization and for an omnidirectional dipole with linear polarization in the LOS, NLOS, and OLOS scenarios.
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Kim, Dang-Oh, Che-Young Kim e Dae-Geun Yang. "Flexible Hilbert-Curve Loop Antenna Having a Triple-Band and Omnidirectional Pattern for WLAN/WiMAX Applications". International Journal of Antennas and Propagation 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/687256.
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A triple-band flexible loop antenna is proposed for WLAN/WiMAX applications in this paper. The proposed antenna is formed by the third-order Hilbert-curve and bending type structure which provides flexible characteristics. Even though the radius of the curvature for bending antennas is changed, a triple-band feature still remains in the proposed antenna. Moreover, the antenna exhibits the characteristics of omnidirectional radiation pattern and circular polarization. To verify the receiving performance of antenna, a simulation on the antenna factor was conducted by an EM simulator. Based on these results, the suggested antenna makes a noteworthy performance over typical loop antennas.
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Hatami, Ahmad, e Mohammad Naser‐Moghadasi. "Split ring resonator metamaterial loads for compact Hepta band printed inverted F antenna with circular polarization". Microwave and Optical Technology Letters 60, n.º 10 (26 de setembro de 2018): 2552–59. http://dx.doi.org/10.1002/mop.31367.
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AbstractThe printed inverted F antenna (PIFA) has been developed in various shapes for the wireless application. In this paper, we have developed a novel shape based on loop antenna where it is in interaction with the split ring resonator (SRR) load and the extended ground by two vias for multi‐band antenna to cover, GSM900, GSM1800, UMTS, GSM1900, WCDMA 100, 802.11b/g, LTE2600, and 802.11a/n. The antenna total dimensions are 100 mm × 60 mm and it is fabricated on a low‐cost FR‐4 substrate. The prototype antenna has omnidirectional pattern and VSWR is lower than 3 for wireless requested frequency. We obtained 2‐4 dBi antenna gain plus 70% efficiency and circular polarization at 2.5 and 5.5 GHz. The prototype antenna shows low SAR for GSM 900 and GSM 1800 while it has checked for 1 g and 10 g with maximum value of 0.942 and 1.27 W/kg for 900 and 1800 MHz, respectively. In this new survey, the SAR value is decreased sensitively as per previous range in PIFA. The prototype has simulated with HFSS and CST that we used full wave method in both simulation software and finally we compared simulation and experimental result.
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Chowdhury, Piyas, Nishako Chakma, Abu Hena Murshed, Md Azad Hossain e Quazi Delwar Hssain. "An improved 2×2 array antenna using both-sided microwave integrated circuit technology for circular polarization". International Journal of Electrical and Computer Engineering (IJECE) 13, n.º 1 (1 de fevereiro de 2023): 619. http://dx.doi.org/10.11591/ijece.v13i1.pp619-628.
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<span lang="EN-US">A circularly polarized microstrip patch array antenna using both-sided microwave integrated circuit (MIC) technology with a triple feed network has been proposed in this article. The antenna elements, feed structure and both-sided <a name="_Hlk112828933"></a>MIC technology are used and arranged in such a way to obtain circular polarization alongside high gain without using an external matching circuit. The 50 Ω microstrip line is used to energize the antenna where the antenna’s total feed network is made up of both series and parallel combinations of microstrip and slot line. The antenna was realized using Teflon glass fiber substrate </span><em><span lang="EN-US">(ε<sub>r</sub>)</span></em><span lang="EN-US">=2.15 with a thickness of 0.8 mm. The antenna has some splendid parameters including S<sub>11</sub> of less than -35 dB, a gain of 12 dBi with an omnidirectional pattern and an axial ratio of 0.7 dB at the operating frequency. The antenna possesses a bandwidth of 430 MHz (4.22%) after operating at X-band in the frequency spectrum. The antenna’s simulated parameters were investigated with the help of advanced design system (ADS) simulation software in microwave momentum mode.</span>
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Uwano, Shuta, Atsuya Ando, Tomohiro Seki, Yasushi Takatori e Takefumi Hiraguri. "Experimental Investigations of Cochannel Interference Reduction Effect at High Elevation Base Station Using Beam Tilt and Orthogonal Polarization". International Journal of Antennas and Propagation 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/532743.
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This paper addresses the problem of cochannel interference (CCI) generated in a mixed cell architecture in microcellular systems. In this type of microcellular systems in which both microcells and macrocells coexist in the same geographical urban area, the base station antennas mounted on the rooftops of buildings to cover wide circular radio zones suffer severe CCI from the surrounding low base stations. A dielectric-loaded slotted-cylinder antenna (DSCA) is applied to horizontally polarized omnidirectional array antennas in a height-diversity configuration with the high gain of 8 dBi, which is comparable to that of a collinear antenna, to reduce the CCI. The measurements conducted in a suburban area clarify the reduction in the CCI for three techniques. The beam-tilt technique reduces the CCI level by approximately 10 dB for both collinear antennas and the DSCA array antennas. The use of horizontal polarization reduces the CCI level by approximately 13 dB for the DSCA array antennas with and without beam tilt. The combination of the beam tilt and horizontal polarization or the DSCA array antennas with beam tilt significantly reduces the CCI level by approximately 23 dB.
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Ouberri, Fatima, Abdelali Tajmouati, Jamal Zbitou e Mohamed Latrach. "A new design of a printed reconfigurable coplanar multiband antenna". Indonesian Journal of Electrical Engineering and Computer Science 28, n.º 1 (1 de outubro de 2022): 234. http://dx.doi.org/10.11591/ijeecs.v28.i1.pp234-240.
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The demand for multi-functional components has increased enormously in recent years. Advances in integrated technology have enabled researchers to adapt diverse applications operating at different frequencies in a single wireless device. A compact broadband coplanar waveguide (CPW)-fed square aperture monopole antenna with inverted-L grounded strips is first described. The proposed antenna has a small size of 60×60×0.74 mm3 and has excellent performances which include a good input impedance matching with a much wider operating bandwidth, an excitation of the circular polarization at 2.45 GHz, and a stable omnidirectional radiation pattern. Then, a multiband reconfigurable antenna design is developed from this structure. The frequency reconfigurable approach is obtained using a varactor diode. In this work, it is observed that frequency diversity can be obtained by varying the value of the capacity by leaving the dimensions antenna unchanged. The results are given using CST microwave studio and show good performances in terms of return loss, bandwidth, gain and radiation pattern and demonstrate that the proposed antenna offers a reconfigurable solution for multi-standard wireless communication applications.
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Wei, Zhang, e Yang Junfeng. "A Design of Vertical Polarized Conformal Antenna and Its Array Based on UAV Structure". International Journal of Antennas and Propagation 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/9769815.
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The designs of conformal antenna and its array usually need to combine with different carrier structures. As for cone or cylindrical carrier, through using of invasive weed optimization (IWO), the conformal array should be the optimized design as the antenna installation space requirements of cylindrical carrier; through adopting the antenna unit miniaturization method, it designs out a conformal antenna and makes it easier to be installed and the omnidirectional circular polarized beam is also realized. As for unmanned aircraft carrier, it designs out the low profile of conformal vertical polarization antenna unit; through using the electric field integral equation (EFIE) and electric/magnetic current combined-field integral equation (JMCFIE) and multilevel fast multipole algorithm (MLFMA), it analyzes the two different characteristics of unmanned aircraft carrier on the influence of antenna performance. The results obtained through experiments and JMCFIE analysis are in good agreement; according to unmanned aircraft carrier, it also designed out the antenna in X/K-band spectrum; through IWO, the antenna array is optimized; the test results show that the array scanning angle can reach the corresponding beam direction.
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Rao, Dr K. Babu. "Enhanced Circularly Polarized Antenna for Body Centric Communication". International Journal for Research in Applied Science and Engineering Technology 12, n.º 4 (30 de abril de 2024): 3030–41. http://dx.doi.org/10.22214/ijraset.2024.60580.
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Abstract: This study introduces a miniaturized circularly polarized ultra-wideband (UWB) antenna designed specifically for body-centric communication applications, with a focus on its performance across different frequencies. Fabricated on jean fabric, the antenna offers exceptional flexibility and seamless integration into clothing, making it ideal for wearable devices. The design achieves circular polarization through the utilization of an asymmetric stepped L-shaped ground plane and a crossshaped stub integrated into the radiator structure.Operating across the UWB frequency spectrum ranging from 3 GHz to 9.5 GHz, the antenna exhibits consistent and reliable performance in terms of gain, radiation pattern, and current distribution. ensuring effective signal transmission and reception. Importantly, the antenna complies with FCC specific absorption rate (SAR) limits, ensuring safety in wearable applications.Throughout the frequency range, the antenna maintains an omnidirectional radiation pattern, facilitating reliable on-body communication regardless of orientation. This characteristic is crucial for maintaining connectivity and signal quality in body-centric communication systems.Analysis of the current distribution confirms the antenna's effectiveness across different frequency bands, further validating its performance and suitability for body-centric communication applications.
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Jaafar, Afiza Nur, Hajar Ja’afar, Yoshihide Yamada, Fatemeh Sadeghikia, Idnin Pasya Ibrahim e Mohd Khairil Adzhar Mahmood. "Design of an axial mode helical antenna with buffer layer for underwater applications". International Journal of Electrical and Computer Engineering (IJECE) 13, n.º 1 (1 de fevereiro de 2023): 473. http://dx.doi.org/10.11591/ijece.v13i1.pp473-482.
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<span lang="EN-US">Recently, there is an increasing demand for high-speed wireless communication network for short-range underwater communication. From previous research, most underwater antennas produced omnidirectional radiation pattern which has lower antenna gain. There are a few considerations that need to be taken if the antenna is designed to operate in water environment. This paper discusses the electromagnetic properties which affect the underwater antenna design. Physical properties such as electrical permittivity and conductivity of water contribute significant effect to the size of the antenna as it influences the behavior of electromagnetic signal that propagates in water. In this study, an axial mode helical antenna with waterproof container is presented which operates at 433 MHz. The axial mode helical antenna has circular polarization and is suitable to support wireless application which is surrounded by some obstruction. The proposed antenna produces a bidirectional radiation pattern by placing it into a waterproof casing. Good agreement between the simulation and measurement results validates the concept. However, a little discrepancy between the simulated and measured results may be attributed to the noise originated from the equipment and the environment.</span>
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Kamal, Shahanawaz, Mohd Fadzil Bin Ain, Ubaid Ullah, Abdullahi S. B. Mohammed, Roslina Hussin, Mohamad Faiz Bin Mohamed Omar, Fathul Najmi et al. "A Low-Profile Quasi-Loop Magneto-Electric Dipole Antenna Featuring a Wide Bandwidth and Circular Polarization for 5G mmWave Device-to-Device Communication". Journal of Electromagnetic Engineering and Science 22, n.º 4 (31 de julho de 2022): 459–71. http://dx.doi.org/10.26866/jees.2022.4.r.110.
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The deployment of the millimeter (mmWave) frequency spectrum by fifth-generation (5G) device-to-device (D2D) wireless networks is anticipated to meet the growing demands for increased capacity. The antenna is regarded of as an important determinant that guarantees the maximum performance of wireless communication. This paper presents a low-profile magneto-electric (ME) dipole antenna for 5G mmWave D2D communication. A single-element quasi-loop radiator was designed to excite horizontal polarization, and a coaxial probe was used to produce vertical polarization. Subsequently, the structure of the radiator was transformed into a two-element quasi-loop antenna to achieve an omnidirectional radiation pattern with relatively enhanced gain. A coaxially fed T-junction microstrip element was implemented to equally distribute the signal between the two quasi-loop radiators and attain proper impedance matching. Furthermore, a pair of shorting pins was introduced into the two-element design to maintain the circularly polarized (CP) radiation. The finest values of the axial ratio and |S<sub>11</sub>| were derived by rigorously optimizing all the geometry parameters. Both single-element and two-element quasiloop antennas were fabricated and characterized experimentally on the air substrate. The advantage of avoiding a physical substrate is to realize a wide bandwidth, circumvent dielectric losses, and ascertain the maximum gain. The measured and simulated results agree thoroughly with each other. Stable in-band CP radiation were accomplished, thus confirming an appropriate field vector combination from the coaxial probe and the radiator. The finalized antenna engaged an area of ~7.6λ<sup>2</sup><sub>0</sub> for operation at 23.9–30.0 GHz with an axial ratio <3 dB, radiation efficiency ~80%, and gain >5 dBic.
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Shivangi, Soni, Chandan, Kumar Singh Ashutosh e Yadav Hema. "A compact microstrip patch antenna with DGS for WiFi/WiMAX/WLAN". i-manager's Journal on Communication Engineering and Systems 12, n.º 1 (2023): 1. http://dx.doi.org/10.26634/jcs.12.1.19756.
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In recent years, the study of microstrip patch antennas has witnessed significant advancements, offering numerous advantages and promising prospects compared with conventional antennas. These antennas are characterized by their lightweight compact size, low cost, low profile, small dimensions, and excellent conformability. Additionally, microstrip patch antennas exhibit various desirable features, such as dual and circular polarization, dual-frequency operation, broad bandwidth, flexible feedline configurations, and beam-scanning omnidirectional patterns. In this paper, a microstrip patch antenna design tailored for the 2.4 GHz frequency band is proposed, showcasing its potential for applications in wireless communication devices. The antenna is engineered to operate across multiple bands, including the wireless device band, Ultra Wide Band (UWB), and X band. It has a truncated rectangle shape with additional stubs, whereas the substrate material employed is FR4. The resulting design achieves resonance at four different frequencies, effectively covering the Microwave Access (WiMAX) band at 2.5 GHz and 4 GHz. Notably, the implementation of Digital Global Systems (DGS) plays a crucial role in reducing the antenna size while simultaneously enhancing its performance. The proposed microstrip patch antenna demonstrates great potential for meeting the increasing demand of modern wireless communication devices. Its multiband operation, compact size, and improved performance, achieved through the integration of DGS, make it a promising candidate for various wireless communication applications.
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Wu, Chen, e Janaka Elangage. "Numerical Study of Extremely Wideband-Modified Biconical Radiation Structures for Electronic Support Measures Application". Electronics 10, n.º 4 (3 de fevereiro de 2021): 369. http://dx.doi.org/10.3390/electronics10040369.
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Using the finite difference time domain (FD-TD) method, this paper studies radiation structures that can have multiple tunable frequency bands between 0.4 GHz and 4 GHz, a fixed band in [3.97, 5.36] GHz and an extremely wideband from 6.14 GHz to 68.27 GHz, where a frequency band is defined by the voltage standing wave ratio (VSWR) less than or equal to two. The base radiation structure has a modified-biconical antenna configuration, called base MBA, and is fed by a square-coaxial line with characteristic impedance close to 50 ohms. A dielectric ring and an outer dielectric cover are used between the two modified cones to enlarge the frequency band and strengthen the structure. An equal number of metallic-rings can be stacked at both circular-ends of cones in the base MBA to tune the positions of the frequency bands that are lower than 4 GHz and to alter their vertical polarization (V-pol) patterns. However, compared with those of the base MBA, these stacked metallic rings do not make significant changes to the VSWR in the [3.97, 5.36] GHz and [6.14, 28.27] GHz bands and the radiation patterns in the [6.14, 28.27] GHz band. The simulation results show that the base MBA and its metallic-ring-loaded versions all have V-pol radiation characteristics at all frequency bands and have donut-shaped omnidirectional patterns only when the wavelength is bigger than the length of the structure. When the wavelength is less than the size of the radiation structure, the donut shape is modified with ripples on the V-pol radiation pattern. Sometimes deep notches could be observed when MBAs operated at the higher end of the extremely wideband. A 0.2 mm cube was used to construct the antenna structures with the consideration of using the 3D metal/dielectric printer technology to build the antennas in the future.
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Gao, Guo‐Ping, Dan Wang, Ge Ma, Shi‐Chen Wang, Zhi‐Heng Dou e Bin Hu. "A dual‐band dual‐polarized omnidirectional patch antenna for on‐body application". Microwave and Optical Technology Letters 66, n.º 3 (27 de fevereiro de 2024). http://dx.doi.org/10.1002/mop.34050.
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AbstractAiming at the 3.5 GHz world interoperability for microwave access band and 5.8 GHz industrial scientific medical band, a dual‐band antenna operating in omnidirectional mode is proposed. The antenna uses a single‐layer dielectric substrate made of FR‐4, which is cheap and easy to process. It uses circular patches and metal branches to generate orthogonal electric fields to achieve circular polarization. At the same time, the upper patch is symmetrically slotted in a T shape, so that the patch produces two resonance frequencies. The measured impedance bandwidth of the antenna in circular polarization on‐body mode and linear polarization on‐body mode is 110 MHz (3.41–3.52 GHz) and 460 MHz (5.42–5.88 GHz), respectively. In addition, the antenna shows good performance under bending conditions and close to human tissue. At the same time, the low specific absorption rate value proves that the antenna is safe to wear on the human body.
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Cho, SeongYong, Misaki Takahashi, Jun-ichi Fukuda, Hiroyuki Yoshida e Masanori Ozaki. "Directed self-assembly of soft 3D photonic crystals for holograms with omnidirectional circular-polarization selectivity". Communications Materials 2, n.º 1 (31 de março de 2021). http://dx.doi.org/10.1038/s43246-021-00146-x.
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AbstractControlling the crystallographic orientation of 3D photonic crystals is important as it determines the behavior of light propagating through the device. Blue phases self-assemble into unique soft 3D photonic crystals with chiral structures for circular-polarization selectivity, but it has remained a challenge to control its 3D orientation. Here, we show that the orientation of blue phases can be precisely controlled to follow a predefined pattern imprinted on a substrate by exploiting field-induced phase transitions. Obtaining the blue phase through the field-induced chiral nematic phase and tetragonal blue phase X results in a highly oriented blue phase I with the crystallographic [001] direction aligned along the surface anchoring. Our approach is applied to fabricating a Bragg-Berry hologram with omnidirectional circular-polarization selectivity, where the hologram is visible only for one circular-polarization under all incident angles. Such devices are difficult to fabricate using conventional optical materials, thereby demonstrating the potential of self-organizing soft matter for photonics.
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Liang, JiaJun, Zhao Wu, Long Li, Xiuyin Zhang e Hua Yang. "Low‐profile multi‐polarization and pattern reconfigurable antenna based on metasurface". Electronics Letters 59, n.º 16 (agosto de 2023). http://dx.doi.org/10.1049/ell2.12919.
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AbstractIn this letter, a low‐profile metasurface (MS) antenna with multi‐polarization and pattern reconfigurability is presented. The antenna mainly consists of two parts, including a loop antenna fed by balun, and a MS antenna excited by the coupled aperture. When switching the PIN diode and rotating the MS, the multi‐polarization and pattern reconfigurable ability of the antenna is obtained. While the loop antenna is excited, a horizontally linear polarized (HLP) wave and omnidirectional pattern are obtained. Besides, when the MS is operated, due to the differential phase between the orthogonal surface impedance components, the antenna can be switched between vertical linear polarization (VLP), left‐hand circular polarization (LHCP), and right‐hand circular polarization (RHCP). Furthermore, the antenna could achieve a directional pattern. As the simulated and measured results shown, the proposed antenna has an overlapped impedance bandwidth (IMBW) of 24.7% for all polarization modes and a 3‐dB axial ratio (AR) bandwidth of 11.8% for L/RHCP modes. Moreover, the antenna owns a low profile of 0.06 λ (under the operating centre frequency).
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Emadian, Seyed Ramin, e Changiz Ghobadi. "Investigation on a compact wideband omnidirectional circularly polarized antenna in an indoor propagation channel for 2.4 GHz application". International Journal of Communication Systems, 17 de janeiro de 2024. http://dx.doi.org/10.1002/dac.5706.
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SummaryIn this paper, for the first time, the capability of a compact low‐cost wideband omnidirectional circularly polarized (CP) antenna to suppress multipath fading characteristics in a typical indoor propagation channel for 2.4 GHz applications is investigated. A ray tracing method based on the geometrical optics and uniform theory of diffraction is applied to analyze an indoor propagation channel using the measured radiation patterns of the proposed antenna. The design uses a conventional monopole antenna with a circular ground plane to generate a vertically polarized electric field. Sequentially flag‐shaped stubs are then added to the ground plane to produce horizontally polarized electric field and to improve the impedance bandwidth of the proposed antenna. The antenna is designed for 2.4 GHz WLAN application with 10 dB impedance bandwidth of 25.5% and 3 dB axial ratio (AR) bandwidth of 24.5%. The polarization can be readily changed between the left‐hand circular polarization (LHCP) and right‐hand circular polarization (RHCP) by altering the direction of the coaxial probe (monopole) or varying the orientation of the printed bended stubs. Both the LHCP and RHCP prototypes of the proposed antenna are designed, fabricated, and tested, and the similar results are obtained.
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Dudarev, S. V., e D. S. Klygach. "Experimental and numerical simulation of a dual-band omnidirectional printed antenna". Antennas 3 (7 de julho de 2023). http://dx.doi.org/10.18127/j03209601-202303-03.
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Currently, there are many radio engineering and telecommunication systems, the exchange of information in which is carried out using radio signals. For each system, it is necessary to develop new antennas operating in a certain frequency range. Therefore, an urgent problem is development of radiating devices capable of operating simultaneously in two or more wide frequency ranges. This will allow the antenna to be used for multiple applications. The aim of the article is to develop and implement a small-sized printed antenna with a circular pattern in the azimuthal plane and horizontal polarization of the vector E, emitting and receiving a radio signal in the bands corresponding to the GSM-1800, LTE-1800, UMTS-2100 and n79 5G standards. An original design of a multilayer printed antenna with a circular radiation pattern in the azimuthal plane and horizontal polarization has been developed. The antenna consists of two printed circuit boards located one above the other. The bottom board contains a ring array of F-shaped radiators, which is excited using a high-frequency connector. The top board contains an array of passive dipoles that are excited by an electromagnetic field created by a ring array of F-shaped dipoles. According to the calculation results, the antenna emits and receives a radio signal in two frequency ranges: 1,65–2,38 GHz and 4,21–5 GHz (in terms of VSWR = 2). An antenna model has been made, its electrodynamic characteristics have been measured, and the experiment and simulation results have been compared. The developed antenna can be used as an independent radiator or an element of an omnidirectional antenna array of cellular communication standards GSM-1800, LTE-1800, UMTS-2100 and n79 5G.
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Noghanian, Sima. "Textile omnidirectional antenna for wearable WiFi-7 applications using higher order modes". Frontiers in Antennas and Propagation 2 (3 de setembro de 2024). http://dx.doi.org/10.3389/fanpr.2024.1419391.
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In WiFi 7 (IEEE 802.11be), Multiple Input Multiple Output (MIMO) technology plays a crucial role in enhancing throughput. This combination enables numerous applications for wearable WiFi devices. For instance, WiFi can be utilized for tracking and fall detection purposes. Additionally, wearable devices used in gaming, vital signal monitoring, and tracking can benefit from the implementation of wearable MIMO antennas. Despite the demand for wearable WiFi antennas, specifically in the new 6 GHz band, a significant gap exists in the investigation of antennas that are completely made of textile, are low profile, and provide vertical polarization and omnidirectional patterns. Addressing this gap, in this paper, a wearable planar antenna is introduced, which is specifically designed to offer an omnidirectional pattern and linear polarization. To ensure its practicality and ease of use, the antenna utilizes lightweight and wearable textile material. The design details and performance of the proposed antenna are presented. The antenna covers all three bands of WiFi, namely, 2.4 GHz, 5 GHz, and 6 GHz bands. The 10-dB return loss bandwidth is 2.4 GHz–2.5 GHz, and 4.6 GHz–7.2 GHz. The maximum Specific Absorption Rate (SAR) for an input power of 500 mW is calculated at 1.053 W/Kg for a 2 mm air gap between the antenna and tissue surface. The size of the antenna is given by a circular area of π × (50 mm)2, and a thickness of 6 mm.
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Dudarev, S. V., D. S. Klygach e A. V. Dudarev. "Multilayer printed antenna with circular directional pattern and increased directional coefficient". Radioengineering 10 (1 de outubro de 2023). http://dx.doi.org/10.18127/j00338486-202310-18.
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Formulation of the problem. The article explores the possibility of using an array of square open frames to increase the directivity of a multilayer printed antenna with a circular radiation pattern in the azimuthal plane and horizontal polarization. Target. Develop a multi-layer dual-band antenna with increased directivity, emitting/receiving a radio signal in all directions in the azimuthal plane with horizontal polarization. First frequency range: GSM-1800, LTE-1800, UMTS-2100; second frequency band: n79 5G. Results. A new design of a multilayer antenna is proposed, consisting of three printed circuit boards located one above the other. A circular antenna array of F-shaped radiators is placed on the lower dielectric substrate. It is excited by a high-frequency connector. The second board contains arc-curved dipoles located along two circles of different diameters. On the third dielectric substrate there is an array of 45 square open frames. The electrodynamic characteristics of the antenna are calculated and the influence of the array of frames on the directivity coefficient is studied. The antenna operates in two frequency ranges 1.62…2.32 GHz and 4.23…4.95 GHz, the maximum directivity in the first frequency range is 1.9 dB, and in the second 4.6 dB. Practical significance. The antenna can be used as an element of an omnidirectional antenna array of cellular communications of 2-5G generations, to implement the Internet of Things technology, to communicate with moving objects.
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Geyikoglu, Mirac Dilruba. "FLEXIBLE UWB CIRCULAR POLARIZED SIX-PORT MIMO ANTENNA FOR INTERNET OF MEDICAL THINGS-BASED SMART BELTS". Physica Scripta, 10 de outubro de 2024. http://dx.doi.org/10.1088/1402-4896/ad85ae.
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Abstract This study presents a six-port multiple-input and multiple-output (MIMO) antenna developed to meet the diversity requirements of body-centered communication in the Internet of Medical Things (IoMT) based smart belts. The proposed antenna consists of six identical elements with a coplanar waveguide (CPW) structure. The antenna achieves a small profile area of 36 × 42 mm and a height of 0.76 mm with the careful placement of its elements. There are circular patches and a CPW feed structure at the center of the antenna. The distance between the ground and the patch is set intuitively by considering the mutual coupling effect. The effect of the current distribution is increased, and a wide operating range is achieved by adding symmetrical circular slots to soil surfaces. As a proof of configuration, the simulation results are supported by a mesh network equivalent circuit model. The proposed antenna has a bandwidth of 177% in the 0.9-15 GHz frequency range at -6 dB reference. Moreover, it also has an omnidirectional radiation pattern and circular polarization. The peak gain value is 7.8 dBi, and the efficiency value is approximately 90%. ECC, DG, TARC, and CCL parameter measurements were analyzed for performance evaluation of MIMO antennas. In addition, bending tests are also examined. The specific absorption rate (SAR) of the proposed antenna in tissues is evaluated by using infrared thermography. The results indicate that the SAR values are lower than international standards. The antenna design is specifically optimized to exhibit robust behavior when worn by an individual.
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Subbaraj, Sangeetha, e Shweta B. Thomas. "Reconfigurable Antennas and their Practical Applications‐ A Review". Radio Science, 11 de setembro de 2023. http://dx.doi.org/10.1029/2023rs007656.
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AbstractThis paper presents the review on the design of various reconfigurable antennas and their applications in the current scenario. There are more challenges involved in the design of these antennas. This paper also describes the various methods used for reconfiguring the frequency bands. The single parameter reconfiguration and hybrid reconfiguration examples are analyzed with their performances. The parameters such as gain, efficiency, size of the existing antenna is compared. The various switches deployed in the antenna for achieving the reconfiguration are presented in this paper. The switches such as pin diodes, varactor diodes, MEMS and mechanical switching are also elaborated with their corresponding merits and demerits. The diodes are switched on and off to activate and deactivate the structure of the antenna. Similarly, mechanical actuators are used for mechanical switching mechanism. The polarization reconfiguration mechanism between linear and circular; pattern reconfiguration mechanism between directional and omnidirectional are reviewed with various examples. In addition to that, several designs of reconfigurable filtering antennas, MIMO antennas are also reviewed in detail.This article is protected by copyright. All rights reserved.
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Lee, Doojin, e Alexander Yakovlev. "Investigation of dual-mode cloaked cylindrical slot antennas with a pulsed radar signal processing". AIP Advances 14, n.º 10 (1 de outubro de 2024). http://dx.doi.org/10.1063/5.0231729.
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In this paper, the cloaked slot antennas (CSAs) in a circular conducting cylinder have been proposed, numerically studied, and fundamentally characterized with respect to the pulsed radar aspects. The two cylindrically slotted antennas have been introduced, namely the axially slotted cloaked antenna and the circumferentially slotted cloaked antenna (CSCA). These two cloaked slot antennas have been parametrically studied to explore the antenna’s resonant characteristics together with their cloaking performance. The resonant frequency of the antennas is controlled by the parameters of the aperture of the slot such as width and length, while independently cloaking the CSAs at the cloaking frequency controlled by the parameters of the coated metasurface. The characteristics of the dual-mode operation at resonant and cloaking frequencies have been intensively studied by pulsed radar signal processing. The modulated Gaussian pulse with the modulation frequency being either resonant or cloaking frequency is used as an excitation source. Several scenarios have been proposed and studied to characterize the cloaking performance and communication capacity of the cloaked slot antennas. The radiating pulse from the CSAs has been numerically characterized by a pulse radar signal processing with an interval of 22.5° in terms of the theta and phi polarizations. These two CSAs have directive and omnidirectional characteristics in the theta- and phi-polarization, respectively.
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Froes, Eduarda, Paulo F. Silva Junior, Ewaldo E. C. Santana, Carlos M. Sousa Junior, Paulo H. F. Silva, Carlos A. M. Cruz, Vivianne S. Aquino, Luis S. O. Castro, Raimundo C. S. Freire e Mauro S. S. Pinto. "Monopole directional antenna bioinspired in elliptical leaf with golden ratio for WLAN and 4G applications". Scientific Reports 12, n.º 1 (4 de novembro de 2022). http://dx.doi.org/10.1038/s41598-022-21733-z.
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AbstractIn this work, it is proposed the development a new monopole directional antenna, bioinspired in elliptical leaf, with cut by golden ratio, for 4G band application, by the use of the technique of the cut of the radiating element for the increasing of the antenna perimeter, being the first work to use this technique in a bioinspired antenna, promotes resonance frequency turned, and reconfiguring of the antenna parameters as bandwidth, radiation pattern and gain, with the use of the reflector near to the group plane, without the insertion of active devices as the pin diode or change in radiating element. The shape antenna is generated by Gielis formula, built in FR4 substrate, with cuts calculated by golden ratio. To compare the results of the bioinspired monopole on the elliptical sheet, a square-shaped monopole antenna was designed, simulated and measured, the structures were designed in the MATLAB software version 2015(b) and the simulations were performed in the Ansys software version 2016. In the results compared between the square monopole and the bioinspired antenna in the elliptical sheet, it can be seen that the measured bioinspired antenna, compared to the square monopole, presented a bandwidth reduction of 77.27%, a more compact structure, with a reduction of 98%, covering the wireless local area network, and long-time evolution 4G at 2.5 GHz. The proposed technique uses a reflector on the ground plane, to change the parameters of the monopole planar antenna, of omnidirectional radiation pattern to a directional, maintaining the characteristics of the broadband, half-power beamwidth great than 100°, with high current density, and similar gain of a directional antenna. From the results, it has been observed that the elliptical leaf monopole antenna shows broadband characteristics, with a half-power beamwidth of 128°, wideband, the bandwidth of 500 MHz, a gain of 6.28 dBi, a current density of 13.01 A/m2, and circular polarization.