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... 7 shows the test board of this power amplifier using a 5 W GaN HEMT NPTB00004 device. The input matching circuit, output load network, and gate and drain bias circuits (with bypass capacitors on their ends) are fully based on microstrip lines of different electrical lengths and charac- teristic impedances, according to the simulation setup shown in Figure 5. Figure 8 shows the measured results with a maximum output power of 37 dBm, a drain efficiency of 70%, and a PAE of 61.5% with a power gain of 9.5 dB at the operat- ing frequency of 2.14 GHz (gate bias voltage V g = -1.4 ...
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Citations
... The bandwidth is relatively large allowing this device to be used for various communication standards and applications. The chosen GaN HEMT NPTB00004 was also used in 2.14 GHz class E and F amplifiers proposed by Grebennikov [12], [3]. An empirical model of this device is provided by Nitronex which was used for the circuit simulation with Agilent's ADS. ...
... 이론적으로 고효율 특성을 나타내는 스위치 모드 전력 증폭기는 이론적으로는 최대 드레인 효율이 100 %를 얻 을 수 있다. 그러나 주파수가 높아짐에 따라 기생 커패시 턴스의 증가로 손실이 발생하고, 전력증폭소자의 비선형 특성에 의한 선형성의 열화와 스위칭 타이밍에 의한 드 레인 전압과 전류간의 중첩이 발생하기 때문에 이론적으 로 제시하는 100 %의 효율을 얻을 수 없으며, 광대역 특 성을 갖는 전력증폭기 구현이 어렵다 [7], [8] . ...
In order to satisfy the diffusion of multimedia service in mobile communication and the demand for high-speed communication, it is essential to modify and improve high efficiency, wideband and nonlinear characteristic of multiband power amplifier. This research is designed to implement a single-stub matching circuit as a 2nd harmonic one that meets conditions of the Class-J power amplifier. Low characteristic impedance of the single-stub line is necessary to suit conditions of wideband Class-J. This research uses ceramic substrates having high permittivity to implement the single-stub line with low characteristic impedance, which eventually results in an amplifier satisfying the output impedance terms of Class-J in wideband frequency range. This result attributes to use of GaN HEMT packaged with a 2nd harmonic matching circuit and external fundamental circuit. The measurement results of the Class-J amplifier confirms the following characteristics: more than output power of 50 W(47 dBm) in bandwidth of 1.8~2.7 GHz(0.9GHz), maximum drain efficiency of 72.6 %, and maximum PAE characteristic of 66.5 %.
... Most of the hybrid PAs are designed in the low microwave frequency range (L-and S-band, from 1 to 4 GHz) (37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54), which is the appointed frequency for most medium-and high-power applications. Among these, the diffusion of GaN-based device in the last decade has overcome GaAs-and LDMOS-based amplifiers, although the latter are the sole used, in the very recent years, for applications requiring hundred of watts of output power (55)(56)(57). ...
This article is dedicated to the hybrid microwave power amplifiers and to their design. It aims at giving an overview of the topic as complete as possible, although it does not expect to be exhaustive, given the complexity of the subject. Thus, an attempt was made to collect any useful information about hybrid power amplifiers from the designer's point of view. A summary of applications of hybrid power amplifiers is then provided, giving a comprehensive idea of the diffusion of such systems and of their employment according to different power level and frequency bands at which they are required to operate. From a strictly theoretical point of view, this article reports the main characteristic parameters of power amplifiers and their classification as derived from the traditional theory. A distinction between bias classes and operating classes is provided, recalling with some mathematical details different operating modes, in particular current mode and switched mode operations. Apart from mathematical-based statements, this article addresses practical aspects that are essential in the design of a hybrid power amplifier, considering its elementary components and providing a description and an essential bibliography for each of them. Starting from the printed circuit board, which physically constitutes the amplifier, the active components (transistors) and passive components (discrete and distributed) are described, and some considerations about the final assembly are given. Finally, some design examples are provided: In particular, the design of a hybrid microwave power amplifier is detailed step by step, from theoretical aspects to the realization process.Keywords:Microwave power amplifiers;hybrid power amplifiers
... The design of a resistive rectifier, which is placed between the stepped-impedance resonator and the Schottky diode, implies firstly the optimisation of the impedances at the fundamental, second and third harmonic frequency, then preserves the input impedance resistive. Based on the investigation on transmission-line load networks for class-E power amplifiers in [10], a modified distributed-element topology for the input matching network is shown in Fig. 4 The physical length of T L1 is 7.4 mm, its width is 1.7 mm, while the electrical lengths of the open-circuited stub of 30 • is 7.7 mm. To increase symmetry of the circuit, this stub is implemented by using two identical open-circuited stubs in parallel, each having a width of 1.3 mm. ...
This paper proposes an energy recovery rectifier suitable for the use in outphasing and/or linear amplification with nonlinear components (LINC) transmitters. The proposed application oriented rectifier consists of a high-efficiency resistive rectifier and a stepped-impedance resonator (SIR) which stores the energy in order to reduce load sensitivity of the circuit. The rectifier is designed including harmonic frequency control to improve conversion efficiency and to provide a resistive input impedance at the fundamental frequency. The proposed rectifier has been implemented in hybrid technology. The fabricated circuit provides peak RF-to-DC efficiency of 73.5% at 2.3 GHz and more than 60% over a dynamic range of 8 dB. Furthermore, measurements show good agreement with simulation results.
... The bandwidth is relatively large allowing this device to be used for various communication standards and applications. The chosen GaN HEMT NPTB00004 was also used in 2.14 GHz class E and F amplifiers proposed by Grebennikov [12], [3]. An empirical model of this device is provided by Nitronex which was used for the circuit simulation with Agilent's ADS. ...
Power efficiency is a very important specification of power amplifiers for mobile and wireless communication systems. High power efficiency leads to long lasting connection time for mobile, nomadic and wireless devices using battery energy. Especially for public and homeland security applications, long connection time of wireless communication devices is desirable for emergency situations. This paper proposes a high efficiency class E power amplifier with a Gallium Nitride High Electron Mobility Transistor (GaN HEMT) as a power device. A parallel load circuit is used in this class E power amplifier which operates in the frequency range of 140-170 MHz. Furthermore, load-pull technique was applied during the design process to determine the optimal load impedance for the maximum Power-Added Efficiency. Simulation and measurement results of the fabricated class E power amplifier are provided with a peak Power-Added Efficiency (PAE) of 72.5% and power gain of 16.4 dB at 33.9 dBm output power.
... The normalized load network inductance L and capacitance C as a function of the ratio L b /L can be appropriately defined using Eqs. (17), (18) and (21) by ...
... 0 and θ are the characteristic impedance and electrical length of the transmission line TL, respectively[17]. To approximate the idealized parallel-circuit Class E operation conditions for a microwave power amplifier, it is necessary to design the transmission-line load network satisfying the required idealized optimum impedance at fundamental frequency be obtained from Eqs. (51), (52) and (54).By using Eq. ...
In this article, the switched-mode second-order Class E configurations with one capacitor and one inductor and generalized load network including the finite dc-feed inductance, shunt capacitance and series bondwire inductance, which is a part of the transistor output circuit, are discussed. The results of the Fourier analysis and derivation of the equations governing the operation in an idealized operation mode are presented. Based on these equations, the required voltage and current waveforms and load network parameters are determined for both general case and particular circuits corresponding to the sub-harmonic Class E, parallel-circuit Class E and even-harmonic Class E modes. The effect of the device output bondwire inductance on the optimum circuit parameters is demonstrated. The possibilities to realizing the Class E approximation with transmission lines is shown and discussed. Index Terms-power amplifier, high efficiency power amplifier, HBT power amplifier, LDMOS power amplifier, class E power amplifier, MMIC.
This article presents a simulation‐based analysis to first evaluate the impact of excessive transistor output capacitance on class‐E power amplifiers and to second show how inductive compensation can be used to recover optimum class‐E operating conditions. As a starting point, the finite‐feed inductor in a parallel‐circuit topology is replaced by a frequency‐dependent inductor, which in turn can be substituted by a network composed of a series inductor and additional subharmonic resonators. This complex lumped‐element network is then replaced by a generalized transmission line equivalent topology, suitable for microwaves. Calculation of the transmission line impedances and electrical lengths of the proposed generalized network is shown in detail and a design procedure for this modified class‐E is provided. The analysis presented here is further extended by using a simplified large‐signal model for the employed GaN HEMT device, which allows evaluating the effects of non‐ideal switching as well as of capacitance voltage‐dependency and feedback capacitance. The analysis is validated by simulation and design of a test board. Measurements of the test board showed a drain efficiency of 80.3%, power‐added efficiency of 76.3% and output power of 40.1 dBm at 1.96 GHz, demonstrating the validity of the proposed approach.
Magnetically-coupled resonant wireless power transfer systems (WPTs) operating in the megahertz range is well-suited for mid-range transmission of moderate power levels. The class-E power amplifier (PA) is attractive for the MHz WPT applications due to the high-efficiency and soft-switching properties. However, since the output power and the efficiency of the class-E PA strongly depends on the output load, any change in the mutual inductance of coupling coils, which leads to the PA load variation, results in a dramatic loss in the overall performance of WPT system. This paper provides a comprehensive design analysis to analytically and numerically mimic the PA behavior to conveniently adapt any variation of the input impedance of the coupled coils to the PA optimum load using a T-type matching network. An equivalent circuit analysis followed by the design theory for the class-E PA, coupled coils, and the T-network has been presented. For validation purposes, the class-E PA implemented by the cost-effective IRF640 MOSFET was first fabricated and its performance was measured for different load values. The PA efficiency and output power was measured as high as 96.7% and 25.8 W, respectively, for the optimum load value of 9 Ω, which was closely predicted from the theory. A 1 MHz WPT system was then built for the operating range up to 27 cm, showcasing its behavior in presence and absence of the proposed T-type matching circuits at two arbitrary 10 cm and 25 cm distances between the coupling coils; the input impedance of the WPT system for those separation distances were 4 Ω and 0.2 Ω, respectively. Results demonstrate power transfer efficiencies of 88% and 15% at distances of 10 cm and 25 cm with the T-network, respectively, improved by 33% and 12% to the non-matching state, respectively. The overall DC output power achieved using a full-bridge rectifier are 21.9 W and 6.8 W at 10 cm and 25 cm, respectively.
This chapter describes the historical aspects and modern trends of a Class-E power amplifier design. The switchmode Class-E power amplifiers with shunt capacitance have found widespread application because of their design simplicity and high-efficiency operation. Their load-network configuration consists of a shunt capacitor, a series inductor, and a series filter tuned to the fundamental frequency to provide a high level of harmonic suppression. In the Class-E power amplifier, the transistor operates as an on-to-off switch, and the shapes of the current and voltage waveforms provide a condition in which the high current and high voltage do not occur simultaneously. That minimizes the power dissipation and maximizes the power amplifier efficiency. Different circuit configurations and load-network techniques using the push-pull mode, lumped elements, and transmission lines are analyzed. The effects of the power-transistor saturation resistance, finite switching time, and nonlinear shunt capacitance are described. The practical radio frequency and microwave Class-E power amplifiers and their applications are given and discussed.
In this paper, investigation result of a Class-E power
amplifier (PA), using a GaN HEMT, operating at 2 GHz
frequency with 10W output power and better than 82% power
added efficiency (PAE) is reported. The improvement in the
efficiency of the PA has been achieved by the incorporation of an
appropriate input matching network topology. This matching
network transforms the impedance from source to the desired
impedance for conjugate match in addition to suppressing the
second harmonic component of the signal from reaching the gate
of the GaN HEMT. In essence, the suppression of the second
harmonic enables fundamental frequency signal and third
harmonic signal to combine at the gate terminal. It leads to
sharper rising/falling of signal for faster switching of the device
and hence higher power efficiency.
