Journal articles: 'Transistor amplifier in C class'

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S, Muthukumar, and John Wiselin M.C. "Class C Power Amplifier Using GaN Hemt Transistor." Journal of Advanced Research in Dynamical and Control Systems 11, no. 0009-SPECIAL ISSUE (September 25, 2019): 653–60. http://dx.doi.org/10.5373/jardcs/v11/20192618.

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Choi, Hojong. "Class-C Linearized Amplifier for Portable Ultrasound Instruments." Sensors 19, no. 4 (February 21, 2019): 898. http://dx.doi.org/10.3390/s19040898.

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Transistor linearizer networks are proposed to increase the transmitted output voltage amplitudes of class-C amplifiers, thus, increasing the sensitivity of the echo signals of piezoelectric transducers, which are the main components in portable ultrasound instruments. For such instruments, class-C amplifiers could be among the most efficient amplifier schemes because, compared with a linear amplifier such as a class-A amplifier, they could critically reduce direct current (DC) power consumption, thus, increasing the battery life of the instruments. However, the reduced output voltage amplitudes of class-C amplifiers could deteriorate the sensitivity of the echo signals, thereby affecting the instrument performance. Therefore, a class-C linearized amplifier was developed. To verify the capability of the class-C linearized amplifier, typical pulse-echo responses using the focused piezoelectric transducers were tested. The echo signal amplitude generated by the piezoelectric transducers when using the class-C linearized amplifier was improved (1.29 Vp-p) compared with that when using the class-C amplifier alone (0.56 Vp-p). Therefore, the class-C linearized amplifier could be a potential candidate to increase the sensitivity of echo signals while reducing the DC power consumption for portable ultrasound instruments.

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Murtianta, Budihardja. "PENGUAT KELAS D DENGAN METODE SUMMING INTEGRATOR." Elektrika 11, no. 2 (October 8, 2019): 12. http://dx.doi.org/10.26623/elektrika.v11i2.1693.

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A class D amplifier is one in which the output transistors are operated as switches. When a transistor is off, the current through it is zero and when it is on, the voltage across it is small, ideally zero. Thus the power dissipation is very low, so it requires a smaller heat sink for the amplifier. Class D amplifier operation is based on analog principles and there is no digital encoding of the signal. Before the emergence of class D amplifiers, the standard classes were class A, class AB, class B, and class C. The classic method for generating signals driving a transistor MOSFET is to use a comparator. One input is driven by an incoming audio signal, and the other by a triangle wave or a sawtooth wave at the required switching frequency. The frequency of a triangular or sawtooth wave must be higher than the audio input. MOSFET transistors work in a complementary manner that operates as a switch. Triangle waves are usually generated by square waves fed to the integrator circuit. So the main part of processing audio signals into PWM (Pulse Width Modulation) is the integrator and comparator. In this paper, we will discuss the work of a class D amplifier system using the summing integrator method as its main part.

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Petrzela, Jiri. "Generalized Single Stage Class C Amplifier: Analysis from the Viewpoint of Chaotic Behavior." Applied Sciences 10, no. 15 (July 22, 2020): 5025. http://dx.doi.org/10.3390/app10155025.

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This paper briefly describes a recent discovery that occurred during the study of the simplest mathematical model of a class C amplifier with a bipolar transistor. It is proved both numerically and experimentally that chaos can be observed in this simple network structure under three conditions: (1) the transistor is considered non-unilateral, (2) bias point provides cubic polynomial feedforward and feedback transconductance, and (3) the LC tank has very high resonant frequency. Moreover, chaos is generated by an autonomous class C amplifier; i.e., an isolated system without a driving force is analyzed. By the connection of a harmonic input signal, much more complex behavior can be observed. Additionally, due to the high degree of generalization of the amplifier cell, similar fundamental circuits can be ordinarily found as subparts of typical building blocks of a radio frequency signal path.

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Petrzela, Jiri. "New Chaotic Oscillator Derived from Class C Single Transistor-Based Amplifier." Mathematical Problems in Engineering 2020 (November 11, 2020): 1–18. http://dx.doi.org/10.1155/2020/2640629.

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This paper describes a new autonomous deterministic chaotic dynamical system having a single unstable saddle-spiral fixed point. A mathematical model originates in the fundamental structure of the class C amplifier. Evolution of robust strange attractors is conditioned by a bilateral nature of bipolar transistor with local polynomial or piecewise linear feedforward transconductance and high frequency of operation. Numerical analysis is supported by experimental verification and both results prove that chaos is neither a numerical artifact nor a long transient behaviour. Also, good accordance between theory and measurement has been observed.

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Choi, Hojong. "Development of a Class-C Power Amplifier with Diode Expander Architecture for Point-of-Care Ultrasound Systems." Micromachines 10, no. 10 (October 14, 2019): 697. http://dx.doi.org/10.3390/mi10100697.

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Point-of-care ultrasound systems are widely used in ambulances and emergency rooms. However, the excessive heat generated from ultrasound transmitters has an impact on the implementation of piezoelectric transducer elements and on battery consumption, thereby affecting the system’s sensitivity and resolution. Non-linear power amplifiers, such as class-C amplifiers, could substitute linear power amplifiers, such as class-A amplifiers, which are currently used in point-of-care ultrasound systems. However, class-C power amplifiers generate less output power, resulting in a reduction of system sensitivity. To overcome this issue, we propose a new diode expander architecture dedicated to power amplifiers to reduce the effects of sinusoidal pulses toward the power supply. Thus, the proposed architecture could increase the input pulse amplitudes applied to the main transistors in the power amplifiers, hence increasing the output voltage of such amplifiers. To verify the proposed concept, pulse-echo responses from an ultrasonic transducer were tested with the developed class-C power amplifier using a resistor divider and the designed diode expander architecture. The peak-to-peak amplitude of the echo signals of the ultrasonic transducers when using a class-C power amplifier with a diode expander architecture (2.98 Vp–p) was higher than that for the class-C power amplifier with a resistor divider architecture (2.51 Vp–p). Therefore, the proposed class-C power amplifier with diode expander architecture is a potential candidate for improving the sensitivity performance of piezoelectric transducers for point-of-care ultrasound systems.

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Petrzela, Jiri. "Evidence of Strange Attractors in Class C Amplifier with Single Bipolar Transistor: Polynomial and Piecewise-Linear Case." Entropy 23, no. 2 (January 30, 2021): 175. http://dx.doi.org/10.3390/e23020175.

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This paper presents and briefly discusses recent observations of dynamics associated with isolated generalized bipolar transistor cells. A mathematical model of this simple system is considered on the highest level of abstraction such that it comprises many different network topologies. The key property of the analyzed structure is its bias point since the transistor is modeled via two-port admittance parameters. A necessary but not sufficient condition for the evolution of autonomous complex behavior is the nonlinear bilateral nature of the transistor with arbitrary reason that causes this effect. It is proved both by numerical analysis and experimental measurement that chaotic motion is miscellaneous, robust, and it is neither numerical artifact nor long transient motion.

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Modzelewski, Juliusz, and Katarzyna Kulma. "An improved calculation method of inductance and capacitances in π1 circuits for resonant power amplifiers." Archives of Electrical Engineering 61, no. 2 (June 1, 2012): 221–37. http://dx.doi.org/10.2478/v10171-012-0019-x.

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An improved calculation method of inductance and capacitances in π1 circuits for resonant power amplifiers In the paper an improved method of calculation of the inductance and capacitances in the π1 circuit for Class A, AB, B, and C resonant power amplifiers is presented. This method is based on an assumption that the quality factor of the inductor is finite and the capacitors are lossless. The input parameters for calculations are the amplifier load resistance, the transistor load resistance, the quality factor of the inductor, the loaded quality factor of the designed circuit, and the operating frequency. The presented method allows reducing the required regulation range of π1 circuits elements in built resonant amplifiers as compared to the traditional calculation methods assuming lossless capacitors and inductor. This advantage is important, in particular, for long- and medium-wave transistor power amplifiers, where capacitances in π1 circuits are high comparing to typical trimming capacitors.

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WANG, YEN-CHU. "Invited paper. Comparisons of MESFET bipolar transistor and static induction transistor class C amplifiers." International Journal of Electronics 59, no. 1 (July 1985): 1–17. http://dx.doi.org/10.1080/00207218508920674.

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Montesinos, Ronald, Corinne Berland, Mazen Abi Hussein, Olivier Venard, and Philippe Descamps. "Analysis of RF power amplifiers in LINC systems." International Journal of Microwave and Wireless Technologies 4, no. 1 (January 5, 2012): 81–91. http://dx.doi.org/10.1017/s1759078711001085.

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LInear amplification using Non-linear Components (LINC) is an architecture that achieves linear power amplification for radio-frequency (RF) transmitters. This paper describes the impact of RF power amplifiers (PAs) class on the overall system performances. The linearity and efficiency of the LINC transmitter with different PA classes (AB, B, C, D, E, F, F−1, and J) are evaluated and compared, in terms of error vector magnitude (EVM), adjacent channel leakage ratio (ACLR), and power added efficiency (PAE), for a 16QAM modulation having 5.6 dB peak to average power ratio. Simulations are performed using a gallium-nitride high electron mobility transistor (GaN HEMT) for a power amplifier with an output power of 10 W at 900 MHz.

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Azam, Sher, C. Svensson, and Q. Wahab. "Pulse input Class-C power amplifier response of SiC MESFET using physical transistor structure in TCAD." Solid-State Electronics 52, no. 5 (May 2008): 740–44. http://dx.doi.org/10.1016/j.sse.2007.09.022.

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Petrzela, Jiri. "Hyperchaotic Self-Oscillations of Two-Stage Class C Amplifier With Generalized Transistors." IEEE Access 9 (2021): 62182–94. http://dx.doi.org/10.1109/access.2021.3074367.

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13

Yang, Fei, Jun Li, Hongxi Yu, Sen Yan, Anxue Zhang, Kaida Xu, and Zhonghe Jin. "Asymmetric Doherty Power Amplifier with Input Phase/Power Adjustment and Envelope Tracking." Electronics 10, no. 19 (September 23, 2021): 2327. http://dx.doi.org/10.3390/electronics10192327.

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In this paper, the design and implementation of a Doherty power amplifier (DPA) are proposed using gallium nitride high electron mobility transistors (GaN HEMTs). Class-F and Class-C modes are combined to obtain an asymmetric DPA. The precise active load-pull controlling of fundamental and harmonic terminations of the DPA is simulated and analyzed, including the parasitics of the transistors. The measurements of the DPA with the phase difference, input power ratio adjustment, and envelope tracking of the auxiliary PA are discussed in detail in order to achieve a competitive performance. A greater than 63% drain efficiency is obtained within the 10-dB input power dynamic range at 2.1 GHz. The peak of the drain efficiency reaches 73%, with a corresponding output power of 46 dBm.

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Jefferies, D. J., G. G. Johnstone, and J. H. B. Deane. "An experimental search for the conditions for the existence of chaotic states in Class C bipolar transistor RF amplifiers." International Journal of Electronics 71, no. 4 (October 1991): 661–73. http://dx.doi.org/10.1080/00207219108925509.

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Konstantinov, Andrey O., J. O. Svedberg, I. C. Ray, Chris I. Harris, Christer Hallin, and B. O. Larsson. "High Power High Efficiency Lateral Epitaxy MESFETs in Silicon Carbide." Materials Science Forum 527-529 (October 2006): 1231–34. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1231.

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High power high efficiency silicon carbide RF MESFETs are fabricated using a novel structure utilizing lateral epitaxy. The MESFET employs buried p-type depletion stoppers grown by lateral epitaxy with subsequent planarization. The depletion stopper is epitaxially overgrown by the channel layer. The depletion stopper suppresses short channel effects and increases the operation voltage and the RF signal gain at high voltage operation. High breakdown voltages of over 200 Volts are achieved for single-cell components, however large-area transistors are limited to around 150 Volts. Single-cell components measured on-wafer demonstrate an Ft of 10 GHz and high unilateral gain. Packaged 6-mm RF transistors in amplifier circuits feature a saturated power of 20 W and a P1dB of 15W with a linear gain of over 16 dB at Vdd of 60 V for 2.25 GHz operation. Maximum drain efficiency is 56% for class AB operation, 48% at 1 dB compression point and 72% for class C at 2.25 GHz.

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Siri, Mattison S., and David S. Cochran. "Development of a Design Procedure for Class E Amplifiers." MATEC Web of Conferences 223 (2018): 01016. http://dx.doi.org/10.1051/matecconf/201822301016.

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Here, the step-by-step design procedure for a Class E amplifier is presented. An existing Class E amplifier system is described using a systems architecture approach. The design decomposition for the case study is written so that Physical Solutions (PSs; equivalent to Design Parameters) are in terms of component parameters (such as frequency or capacitance). Coupling issues are found to arise given constraints on transistor use. The design decomposition is altered to reflect the case where an amplifier is required to power a specific load. A discussion of transistor failure enables a design procedure to be developed by observing path-dependent coupling. The design procedure is tested through the design of a real amplifier. The designed amplifier is built and its performance measured.

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Choi, Hojong. "Stacked Transistor Bias Circuit of Class-B Amplifier for Portable Ultrasound Systems." Sensors 19, no. 23 (November 29, 2019): 5252. http://dx.doi.org/10.3390/s19235252.

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The performance of portable ultrasound systems is affected by the excessive heat generated by amplifiers, thereby reducing the sensitivity and resolution of the transducer devices used in ultrasound systems. Therefore, the amplifier needs to generate low amounts of heat to stabilize portable ultrasound systems. To properly control the amplifier, the related bias circuit must provide proper DC bias voltages for long time periods in ultrasound systems. To this end, a stacked transistor bias circuit was proposed to achieve a relatively constant amplifier performance irrespective of temperature variance without any cooling systems as the portable ultrasound system structure is limited. To prove the proposed concept, the performance of the gain and DC current consumption at different experimental times was measured and compared to a developed class-B amplifier with different bias circuits. The amplifier with the stacked transistor bias circuit outperformed with regard to the gain and DC current variance versus time (−0.72 dB and 0.065 A, respectively) compared to the amplifier with a typical resistor divider bias circuit (−5.27 dB and 0.237 A, respectively) after a certain time (5 min). Consequently, the proposed stacked transistor bias circuit is a useful electronic device for portable ultrasound systems with limited structure sizes because of its relatively low gain and DC current variance with respect to time.

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Eccleston, K. W., K. J. I. Smith, and P. T. Gough. "A compact class-F/class-C Doherty amplifier." Microwave and Optical Technology Letters 53, no. 7 (April 22, 2011): 1606–10. http://dx.doi.org/10.1002/mop.26035.

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Sabaghi, Masoud, Seyed Reza Hadianamrei, Mehdi Rahnama, and Maziyar Niyakan Lahiji. "Using LDMOS Transistor in Class-F Power Amplifier For WCDMA Applications." International Journal of Communications, Network and System Sciences 04, no. 10 (2011): 662–66. http://dx.doi.org/10.4236/ijcns.2011.410081.

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Song, Ki-Jae, Jong-Chul Lee, Byungje Lee, Jong-Heon Kim, and Nam-Young Kim. "High-efficiency class-C power-amplifier module." Microwave and Optical Technology Letters 40, no. 2 (2003): 164–67. http://dx.doi.org/10.1002/mop.11317.

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Yusop, Yusmarnita, Mohd Shakir Md Saat, Siti Huzaimah Husin, Sing Kiong Nguang, and Imran Hindustan. "Design and Analysis of 1MHz Class-E Power Amplifier for Load and Duty Cycle Variations." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 2 (June 1, 2016): 358. http://dx.doi.org/10.11591/ijpeds.v7.i2.pp358-368.

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<p>This paper presents the simulation and experimental of Class-E power amplifier which consists of a load network and a single transistor. The transistor is operated as a switch at the carrier frequency of the output signal. In general, Class-E power amplifier is often used in designing a high frequency ac power source because of its ability to satisfy the zero voltage switching (ZVS) conditions efficiently even when working at high frequencies with significant reduction in switching losses. In this paper, a 10W Class-E power amplifier is designed, constructed, and tested in the laboratory. SK40C microcontroller board with PIC16F877A is used to generate a pulse width modulation (PWM) switching signal to drive the IRF510 MOSFET. To be specific, in this paper, the effect on switching and performance at 1MHz frequency are studied in order to understand the Class-E inverter behavior. Performance parameters relationships were observed and analysed in respect to the load and duty cycle. Theoretical calculations, simulation and experimental results for optimum operation using selected component values are then compared and presented.</p>

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Pirasteh, Ali, Saeed Roshani, and Sobhan Roshani. "Design of a Miniaturized Class F Power Amplifier Using Capacitor Loaded Transmission Lines." Frequenz 74, no. 3-4 (March 26, 2020): 145–52. http://dx.doi.org/10.1515/freq-2019-0180.

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AbstractIn this paper, a new method to decrease the dimensions of the microstrip structures and reducing the overall size of the class F amplifiers is presented. First, by using the PHEMT transistor with a conventional harmonic control circuit (HCC), a low-voltage class F amplifier in the L band frequency at the operating frequency of 1.75 GHz is introduced, which named primitive class F power amplifier. Then, this amplifier is optimized by using capacitor loaded transmission lines (CLTLs). The measurement results of the amplifier show that by using the CLTL structure, the overall size has been reduced 85% (0.23 λg × 0.17 λg). The maximum power-added efficiency (PAE) of the power amplifier is about 77.5 % and the power gain which has been reached to 18.33 dB. The desirable features of this power amplifier, along with its very small size, make this power amplifier a good choice to use for the global system for mobile communications.

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Yang, Jie, John Fraley, Bryon Western, Marcelo Schupbach, and Alexander B. Lostetter. "A 450°C High Voltage Gain AC Coupled Differential Amplifier." Materials Science Forum 717-720 (May 2012): 1253–56. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.1253.

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APEI, Inc. designed, fabricated and tested a high gain AC coupled differential amplifier based on a custom-built silicon carbide (SiC) vertical junction field effect transistor (VJFET). This SiC differential amplifier is capable of high temperature operation up to 450 °C, at which a high differential voltage gain of more than 47 dB is maintained. This high gain AC coupled differential amplifier can be integrated with harsh environment sensors that deliver weak AC output signals to improve signal quality and noise immunity.

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Abdulhamid, Mohanad, and James Karugu. "On the design of class-J microwave power amplifier." International Review of Applied Sciences and Engineering 10, no. 3 (December 2019): 225–32. http://dx.doi.org/10.1556/1848.2019.0026.

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Due to the ISM band being unlicensed for communication applications, a lot of applications have been developed in this band and a good example is WiFi IEEE 802.11a, b, g, n of Bluetooth. This numeracy of applications motivated this paper. The paper is concerned with the design of a low distortion 20 dBm 2.4 GHz class-J power amplifier (PA) since PAs are indispensable in radio communications. The design is based on the AVAGO ATF-52189 transistor with a transition frequency of 6 GHz. The design is done as a hybrid circuit network realized using microstrip elements and surface mount device (SMD) capacitors. The schematic design and simulation are carried out using Keysight's Advanced Design System version 2016.01. The simulated PA exhibited a drain efficiency of 69% and a power output of 21 dBm.

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Abdulhamid, Mohanad, Karugu James, and Muaayed Farhan. "On the Design of Class-J Microwave Power Amplifier." Scientific Bulletin of Electrical Engineering Faculty 19, no. 1 (April 1, 2019): 6–12. http://dx.doi.org/10.1515/sbeef-2019-0002.

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AbstractDue to the ISM band being unlicensed for communication applications, a lot of applications have been developed in this band and a good example is WiFi IEEE802.11a, b, g, n of Bluetooth. This numeracy of applications motivated this paper. The paper is concerned with the design of a low distortion 20dBm 2.4GHz class-J power amplifier (PA) since PAs are indispensable in radio communications. The design is based on the AVAGO ATF-52189 transistor with a transition frequency of 6GHz. The design is done as a hybrid circuit network realized using microstrip elements and surface mount device (SMD) capacitors. The schematic design, and simulation are carried out using Keysight’s Advanced Design System version 2016.01. The simulated PA exhibited a drain efficiency of 69% and a power output of21dBm.

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Kazimierczuk, M. K., and W. A. Tabisz. "Class C-E high-efficiency tuned power amplifier." IEEE Transactions on Circuits and Systems 36, no. 3 (March 1989): 421–28. http://dx.doi.org/10.1109/31.17589.

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Schmid, Ulf, Rolf Reber, Sébastien Chartier, Kristina Widmer, Martin Oppermann, Wolfgang Heinrich, Chafik Meliani, Rüdiger Quay, and Stephan Maroldt. "GaN devices for communication applications: evolution of amplifier architectures." International Journal of Microwave and Wireless Technologies 2, no. 1 (February 2010): 85–93. http://dx.doi.org/10.1017/s1759078710000218.

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This paper presents the design and implementation of power amplifiers using high-power gallium nitride (GaN) high electronic mobility transistor (HEMT) powerbars and monolithic microwave integrated circuits (MMICs). The first amplifier is a class AB implementation for worldwide interoperability for microwave access (WiMAX) applications with emphasis on a low temperature cofired ceramics (LTCC) packaging solution. The second amplifier is a class S power amplifier using a high power GaN HEMT MMIC. For a 450 MHz continuous wave (CW) signal, the measured output power is 5.8 W and drain efficiency is 18.5%. Based on time domain simulations, loss mechanisms are identified and optimization steps are discussed.

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Rong, Chuicai, Xiansuo Liu, Yuehang Xu, Mingyao Xia, Ruimin Xu, and Tiedi Zhang. "A class E GaN microwave power amplifier accounting for parasitic inductance of transistor." IEICE Electronics Express 14, no. 8 (2017): 20170127. http://dx.doi.org/10.1587/elex.14.20170127.

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Mediano, Arturo, and Nathan O. Sokal. "A Class-$E$ RF Power Amplifier With a Flat-Top Transistor-Voltage Waveform." IEEE Transactions on Power Electronics 28, no. 11 (November 2013): 5215–21. http://dx.doi.org/10.1109/tpel.2013.2242097.

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Yang, Jie, John Fraley, Bryon Western, Marcelo Schupbach, and Alexander B. Lostetter. "An All Silicon Carbide High Temperature (450+ °C) High Voltage Gain AC Coupled Differential Amplifier." Materials Science Forum 679-680 (March 2011): 746–49. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.746.

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APEI, Inc. designed, fabricated and tested a high gain AC coupled differential amplifier based on a custom-built silicon carbide (SiC) vertical junction field effect transistor (VJFET). This SiC differential amplifier is capable of extreme temperature operation up to 450 °C, at which a high differential voltage gain of more than 47 dB is maintained. This high gain AC coupled differential amplifier can be integrated with high temperature sensors that deliver weak AC output signals to improve signal quality and noise immunity.

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Na, Jongyun, Sang-Hwa Yi, Jaekyung Shin, Hyungmo Koo, Jongseok Bae, Keum-Cheol Hwang, Kang-Yoon Lee, and Youngoo Yang. "2.4 GHz GaN HEMT Class-F Synchronous Rectifier Using an Independent Second Harmonic Tuning Circuit." Sensors 21, no. 5 (February 25, 2021): 1608. http://dx.doi.org/10.3390/s21051608.

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This paper proposes a class-F synchronous rectifier using an independent second harmonic tuning circuit for the power receiver of 2.4 GHz wireless power transmission systems. The synchronous rectifier can be designed by inverting the RF output port to the RF input port of the pre-designed class-F power amplifier based on time reversal duality. The design of the class-F power amplifier deploys an independent second harmonic tuning circuit in the matching networks to individually optimize the impedances of the fundamental and the second harmonic. The synchronous rectifier at the 2.4 GHz frequency is designed and implemented using a 6 W gallium nitride high electron mobility transistor (GaN HEMT). Peak RF-dc conversion efficiency of the rectifier of 69.6% is achieved with a dc output power of about 7.8 W, while the peak drain efficiency of the class-F power amplifier is 72.8%.

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Neudeck, Philip G., David J. Spry, Liang Yu Chen, Robert S. Okojie, Glenn M. Beheim, Roger D. Meredith, and Terry L. Ferrier. "SiC Field Effect Transistor Technology Demonstrating Prolonged Stable Operation at 500 °C." Materials Science Forum 556-557 (September 2007): 831–34. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.831.

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While there have been numerous reports of short-term transistor operation at 500 °C or above, these devices have previously not demonstrated sufficient long-term operational durability at 500 °C to be considered viable for most envisioned applications. This paper reports the development of SiC field effect transistors capable of long-term electrical operation at 500 °C. A 6H-SiC MESFET was packaged and subjected to continuous electrical operation while residing in a 500 °C oven in oxidizing air atmosphere for over 2400 hours. The transistor gain, saturation current (IDSS), and on-resistance (RDS) changed by less than 20% from initial values throughout the duration of the biased 500 °C test. Another high-temperature packaged 6H-SiC MESFET was employed to form a simple one-stage high-temperature low-frequency voltage amplifier. This single-stage common-source amplifier demonstrated stable continuous electrical operation (negligible changes to gain and operating biases) for over 600 hours while residing in a 500 °C air ambient oven. In both cases, increased leakage from annealing of the Schottky gate-to-channel diode was the dominant transistor degradation mechanism that limited the duration of 500 °C electrical operation.

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Mabrok, Mussa, Zahriladha Zakaria, Tole Sutikno, and Ammar Alhegazi. "Wideband power amplifier based on Wilkinson power divider for s-band satellite communications." Bulletin of Electrical Engineering and Informatics 8, no. 4 (December 1, 2019): 1531–36. http://dx.doi.org/10.11591/eei.v8i4.1552.

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This paper presents design and simulation of wideband power amplifier based on multi-section Wilkinson power divider. Class-A topology and ATF-511P8 transistor have been used. Advanced Design System (ADS) software used to simulate the designed power amplifier. The simulation results show an input return loss (S11)-10dB, gain (S21)10 dB over the entire bandwidth, and an output power around 28dBm at the Centre frequency of 3GHz. The designed amplifier is stable over the entire bandwidth (K1). Inter-modulation distortion is -65.187dBc which is less than -50dBc. The designed amplifier can be used for the microwave applications which include weather radar, satellite communication, wireless networking, mobile, and TV.

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Wen, Feng, and Rui Li. "Parameter Analysis and Optimization of Class-E Power Amplifier Used in Wireless Power Transfer System." Energies 12, no. 17 (August 22, 2019): 3240. http://dx.doi.org/10.3390/en12173240.

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In this paper, a steady-state matrix analysis method is introduced to analyze the output characteristics of the class-E power amplifier used in a wireless power transfer (WPT) system, which takes the inductance resistance, on-resistance and leakage current of metal-oxide-semiconductor field effect transistor (MOSFET) into account so that the results can be closer to the actual value. On this basis, the parameters of the class-E power amplifier are optimized, and the output power is improved under the premise of keeping the efficiency unchanged. Finally, the output characteristics of the amplifier before and after optimization are compared by an experiment, while the B-field strength around the WPT system is studied through simulation. The experimental results verify the correctness and feasibility of the optimization method based on steady-state matrix analysis.

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Krizhanovski, V. G., D. G. Makarov, and A. A. Kistchinsky. "Class E microwave amplifier built on a SiC transistor with high on-state resistance." Radioelectronics and Communications Systems 53, no. 6 (June 2010): 290–98. http://dx.doi.org/10.3103/s0735272710060026.

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Raicevic, Andjelija. "Amplitude modulator in class e with the current mirror in emitter circuits of the switching transistor." Facta universitatis - series: Electronics and Energetics 21, no. 2 (2008): 243–49. http://dx.doi.org/10.2298/fuee0802243r.

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Starting from the fact that the amplitude of the basic harmonics of the current, flowing through load resistor of the class E power amplifier, is proportional to direct current flowing through the collector battery of the switching transistor, an introduction of a current mirror in emitter circuit of the transistor in whose reference branch is situated a generator of modulating voltage is proposed. It can be easily proven that the total current of this mirror, which is also the direct current of the collector battery, has the waveform of the amplitude modulated signal. This amplitude modulator is verified for performance with pSpace model. .

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Li, Zhichao, Shiheng Yang, Samuel B. S. Lee, and Kiat Seng Yeo. "A Two-Stage X-Band 20.7-dBm Power Amplifier in 40-nm CMOS Technology." Electronics 9, no. 12 (December 20, 2020): 2198. http://dx.doi.org/10.3390/electronics9122198.

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For higher integration density, X-band power amplifiers (PAs) with CMOS technology have been widely discussed in recent publications. However, with reduced power supply voltage and device size, it is a great challenge to design a compact PA with high output power and power-added efficiency (PAE). In the proposed design, a 40-nm standard CMOS process is used for higher integration with other RF building blocks, compared with other CMOS PA designs with larger process node. Transistor cells are designed with neutralization capacitors to increase stability and gain performance of the PA. As a trade-off among gain, output power, and PAE, the transistor cells in driving stage and power stage are biased for class A and class AB operation, respectively. Both transistor cells consist of two transistors working in differential mode. Furthermore, transformer-based matching networks (TMNs) are used to realize a two-stage X-band CMOS PA with compact size. The PA achieves an effective conductivity (EC) of 117.5, which is among the highest in recently reported X-band PAs in CMOS technology. The PA also attains a saturated output power (Psat) of 20.7 dBm, a peak PAE of 22.4%, and a gain of 25.6 dB at the center frequency of 10 GHz under a 1 V supply in 40-nm CMOS.

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NG, K. M., S. HINCHLIFFE, and L. HOBSON. "An RF Class C power amplifier for dielectric heating applications." International Journal of Electronics 62, no. 4 (April 1987): 521–32. http://dx.doi.org/10.1080/00207218708921003.

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Telegdy, A., B. Molnar, and N. O. Sokal. "Class-E/sub m/ switching-mode tuned power amplifier-high efficiency with slow-switching transistor." IEEE Transactions on Microwave Theory and Techniques 51, no. 6 (June 2003): 1662–76. http://dx.doi.org/10.1109/tmtt.2003.812562.

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Rachakh, Amine, Larbi El Abdellaoui, Jamal Zbitou, Ahmed Errkik, Abdelali Tajmouati, and Mohamed Latrach. "A Novel Design of a Microstrip Microwave Power Amplifier for DCS Application using Collector-Feedback Bias." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 3 (June 1, 2018): 1647. http://dx.doi.org/10.11591/ijece.v8i3.pp1647-1653.

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This paper presents a 1.80GHz class-A Microwave power amplifier (PA). The proposed power amplifier is designed with single-stage architecture. This power amplifier consists of a bipolar transistor and improved by Collector-Feedback Biasing fed with a single power supply. The aim of this work is to improve the performance of this amplifier by using simple stubs with 50Ω microstrip transmissions lines. The proposed PA is investigated and optimized by utilizing Advanced Design System (ADS) software. The simulation results show that the amplifier achieves a high power gain of 13dB, output power rise up to 21dBm and good impedances matching ;For the input reflection coefficient (S11) is below than - 46.39dB. Regarding the output reflection coefficient (S22) is below than -29.898dB, with an overall size of about 93 x 59mm². By the end; we find that this power amplifier offers an excellent performance for DCS applications.

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Saad, Paul, Christian Fager, Hossein Mashad Nemati, Haiying Cao, Herbert Zirath, and Kristoffer Andersson. "A highly efficient 3.5 GHz inverse class-F GaN HEMT power amplifier." International Journal of Microwave and Wireless Technologies 2, no. 3-4 (June 11, 2010): 317–24. http://dx.doi.org/10.1017/s1759078710000395.

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This paper presents the design and implementation of an inverse class-F power amplifier (PA) using a high power gallium nitride high electron mobility transistor (GaN HEMT). For a 3.5 GHz continuous wave signal, the measurement results show state-of-the-art power-added efficiency (PAE) of 78%, a drain efficiency of 82%, a gain of 12 dB, and an output power of 12 W. Moreover, over a 300 MHz bandwidth, the PAE and output power are maintained at 60% and 10 W, respectively. Linearized modulated measurements using 20 MHz bandwidth long-term evolution (LTE) signal with 11.5 dB peak-to-average ratio show that −42 dBc adjacent channel power ratio (ACLR) is achieved, with an average PAE of 30%, −47 dBc ACLR with an average PAE of 40% are obtained when using a WCDMA signal with 6.6 dB peak-to-average ratio (PAR).

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Haldar, Devasis, Shagun Panwar, Vipul Kumar, Ayush Goswami, and Sakshi Dhawan. "Circuits for Optical Based Line of Sight Voice Communication." Bulletin of Electrical Engineering and Informatics 6, no. 1 (March 1, 2017): 76–80. http://dx.doi.org/10.11591/eei.v6i1.592.

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We present here line of sight communication between a person and his neighbour with the help of optical signal produced by a laser torch which act as a carrier. It is therefore a wireless communication and the transmission can go up to 500 meters. We used photodiode to receive the signal at the receiver. The transmitter circuit comprises condenser microphone transistor amplifier BC547 followed by an op-amp stage built around µA741. When we give a voice signal from the mike, it converts the voice signal into the electrical signal. This electrical signal is fed to IC741 (op-amp) for amplification. The gain of the op-amp can be controlled with the help of 1-mega-ohm potentiometer. The AF output from IC is coupled to the base of a class B amplifier which, in turn, modulates the signal. The transmitter uses 5V power supply. However, the 3-volt laser torch (after removal of its battery) can be directly connected to the circuit-with the body of the torch connected to the class B. The photodiode converts the optical signal into electrical signal and again this signal is amplified using IC741 and a combination of class B push pull amplifiers. The receiver circuit uses an NPN photodiode as the light sensor that is followed by a two-stage transistor preamplifier and IC741 based audio Power amplifier. The receiver does not need any complicated alignment. Just keep the photodiode oriented towards the remote transmitter’s laser point and adjust the volume control for a clear sound. The sensor must not directly face the sun.

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Cheng, Zhiqun, Xuefei Xuan, Huajie Ke, Guohua Liu, Zhihua Dong, and Steven Gao. "Design of 0.8–2.7 GHz High Power Class-F Harmonic-Tuned Power Amplifier with Parasitic Compensation Circuit." Active and Passive Electronic Components 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/2543917.

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The design, implementation, and measurements of a high efficiency and high power wideband GaN HEMT power amplifier are presented. Package parasitic effect is reduced significantly by a novel compensation circuit design to improve the accuracy of impedance matching. An improved structure is proposed based on the traditional Class-F structure with all even harmonics and the third harmonic effectively controlled, respectively. Also the stepped-impedance matching method is applied to the third harmonic control network, which has a positive effect on the expansion bandwidth. CGH40025F power transistor is utilized to build the power amplifier working at 0.8 to 2.7 GHz, with the measured saturated output power 20–50 W, drain efficiency 52%–76%, and gain level above 10 dB. The second and the third harmonic suppression levels are maintained at −16 to −36 dBc and −16 to −33 dBc, respectively. The simulation and the measurement results of the proposed power amplifier show good consistency.

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Rezaei, Saeed, Leonid Belostotski, Mohamed Helaoui, and Fadhel M. Ghannouchi. "Harmonically Tuned Continuous Class-C Operation Mode for Power Amplifier Applications." IEEE Transactions on Microwave Theory and Techniques 62, no. 12 (December 2014): 3017–27. http://dx.doi.org/10.1109/tmtt.2014.2364836.

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Wang, Dehan, Wenhua Chen, Xiaofan Chen, Fadhel M. Ghannouchi, and Zhenghe Feng. "A Broadband Millimeter-Wave Continuous-Mode Class-F Power Amplifier Based on the Deembedded Transistor Model." IEEE Microwave and Wireless Components Letters 30, no. 6 (June 2020): 609–12. http://dx.doi.org/10.1109/lmwc.2020.2988347.

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Gao, Shengjie, Zhebin Wang, and Chan-Wang Park. "Characterization of transistor using multiharmonic source and load pull tuners for inverse class-F power amplifier." Microwave and Optical Technology Letters 56, no. 10 (July 22, 2014): 2313–20. http://dx.doi.org/10.1002/mop.28583.

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Shirata, Masaki, Toshio Shinohara, Minoru Sato, and Yasushi Itoh. "An L-band SiGe HBT differential amplifier with frequency and rejection-level tunable, multiple stopband." International Journal of Microwave and Wireless Technologies 1, no. 4 (June 22, 2009): 285–92. http://dx.doi.org/10.1017/s1759078709990390.

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An L-band frequency and rejection-level tunable SiGe HBT differential amplifier with dual stopband is presented. To achieve frequency and rejection-level tunable performance, dual LCR-tank circuit with an active load is incorporated into the design of the series feedback loops of the differential amplifier. The active load consists of a varactor diode represented as a variable C and a common-emitter transistor represented as a variable R. The frequency and rejection level can be tuned independently by controlling a cathode bias voltage of the varactor diode or a base bias voltage of the transistor. The implemented 0.35 μm SiGe HBT amplifier with dual stopband demonstrates a frequency tuning of 0.53–1.16 GHz and a rejection-level variation up to 9.5 dB. The input and output return losses are better than 17.5 and 11 dB over 0.2–1.5 GHz, respectively. The measured P1dB is+3 dBm and IIP3 is 0 dBm with Vcc = 6 V and Ic = 8 mA.

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Mabrok, Mussa, Zahriladha Zakaria, and Nasrullah Saifullah. "Design of Wide-band Power Amplifier based on Power Combiner Technique with Low Intermodulation Distortion." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 5 (October 1, 2018): 3504. http://dx.doi.org/10.11591/ijece.v8i5.pp3504-3511.

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RF power amplifiers are one of challenging blocks in designing radio frequency transceivers, this is due to non-linearity behavior of power amplifiers that leads to inter-modulation distortion. This paper presents the design of wide-band power amplifier which combined with parallel coupled line band pass filter at the input and output of power amplifier to allow the only required frequency band to pass through the power amplifier. Class-A topology and ATF-511P8 transistor are used in this design. Advanced Design System software used as a simulation tool to simulate the designed wide-band power amplifier. The simulation results showed an input return loss (S11) which less than -10dB, and gain (S21) is higher than 10 dB over the entire frequency band and considers as flat as well. The designed amplifier is stable over the bandwidth (K>1). Inter-modulation distortion is -56.919dBc which is less than -50dBc with 10dBm input power. The designed amplifier can be used for the microwave applications which include weather radar, satellite communication, wireless networking, mobile, and TV.

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Liu, Ching-Yao, Guo-Bin Wang, Chih-Chiang Wu, Edward Chang, Stone Cheng, and Wei-Hua Chieng. "Derivation of the Resonance Mechanism for Wireless Power Transfer Using Class-E Amplifier." Energies 14, no. 3 (January 26, 2021): 632. http://dx.doi.org/10.3390/en14030632.

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In this study, we investigated the resonance mechanism of 6.78 MHz resonant wireless power transfer (WPT) systems. The depletion mode of a gallium nitride high-electron-mobility transistor (GaN HEMT) was used to switch the states in a class-E amplifier circuit in this high frequency. The D-mode GaN HEMT without a body diode prevented current leakage from the resonant capacitor when the drain-source voltage became negative. The zero-voltage switching control was derived according to the waveform of the resonant voltage across the D-mode GaN HEMT without the use of body diode conduction. In this study, the effect of the resonant frequency and the duty cycle on the resonance mechanism was derived to achieve the highest WPT efficiency. The result shows that the power transfer efficiency (PTE) is higher than 80% in a range of 40 cm transfer distance, and the power delivered to load (PDL) is measured for different distances. It is also possible to cover different applications related to battery charging and others using the proposed design.

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Ali, Firas M., Mahmuod H. Al-Muifraje, and Thamir R. Saeed. "An Analytic Design Approach to Inverse Class-F RF Power Amplifiers." Engineering and Technology Journal 38, no. 2A (February 25, 2020): 211–25. http://dx.doi.org/10.30684/etj.v38i2a.301.

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The design of high efficiency inverse class-F (class-F-1) radio frequency (RF) power amplifiers includes extensive measurements to characterize the RF power device by means of the empirical load-pull test setup. This paper presents an alternative characterization approach based on evaluating the load impedances analytically at the desired harmonic frequencies for a high electron mobility transistor (HEMT) in terms of the internal and package elements of the active device. It additionally provides a method for extracting the parasitic elements of the power device as well as determining the optimum load-line resistance using the transistor manufacturer’s large signal model. A new topology for the output matching circuit is also proposed with its synthetic procedure to present the appropriate harmonic load impedances. To verify this methodology, a 900 MHz inverse class-F power amplifier circuit was designed and its performance was tested with the aid of the Keysight ADS software. The simulation results showed an output power of 38 dBm, a power gain of about 13 dB, DC-to-RF efficiency greater than 87%, and an acceptable level of linearity for both GSM and CDMA modulated signals.

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Journal articles on the topic 'Transistor amplifier in C class'

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