Design Of class-E Power Amplifier Research Articles

A New Design Method for Class-E Power Amplifiers Using Artificial Intelligence Modeling for Wireless Power Transfer Applications

This paper presents a new approach to simplify the design of class-E power amplifier (PA) using hybrid artificial neural-optimization network modeling. The class-E PA is designed for wireless power transfer (WPT) applications to be used in biomedical or internet of things (IoT) devices. Artificial neural network (ANN) models are combined with optimization algorithms to support the design of the class-E PA. In several amplifier circuits, the closed form equations cannot be extracted. Hence, the complicated numerical calculations are needed to find the circuit elements values and then to design the amplifier. Therefore, for the first time, ANN modeling is proposed in this paper to predict the values of the circuit elements without using the complex equations. In comparison with the other similar models, high accuracy has been obtained for the proposed model with mean absolute errors (MAEs) of 0.0110 and 0.0099, for train and test results. Moreover, root mean square errors (RMSEs) of 0.0163 and 0.0124 have been achieved for train and test results for the proposed model. Moreover, the best and the worst-case related errors of 0.001 and 0.168 have been obtained, respectively, for the both design examples at different frequencies, which shows high accuracy of the proposed ANN design method. Finally, a design of class-E PA is presented using the circuit elements values that, first, extracted by the analyses, and second, predicted by ANN. The calculated drain efficiencies for the designed class-E amplifiers have been obtained equal to 95.5% and 91.2% by using analyses data and predicted data by proposed ANN, respectively. The comparison between the real and predicted values shows a good agreement.

Analysis and design of class-E power amplifier considering MOSFET nonlinear capacitance

Class-E power amplifiers are integrated into many applications because their simple design and high performance. The efficiency of the power amplifier is significantly impacted by the nonlinear characteristic of the switching device, which is not analyzed clearly in theory. The nonlinear drain-to-source parasitic capacitance of the power transistor and the linear external capacitance are both contributed to the optimum conditions for obtaining the exact shunt capacitance. In this paper, a high-efficiency class-E power amplifier with shunt capacitance is designed with the consideration of both linear and nonlinear capacitance. Furthermore, a mathematical analysis is derived to calculate the component values in order to design the class-E power amplifier. Consequently, high power-added efficiency of 94.6% is obtained using MRF9030 MOSFET transistor with parameter of 4W output power and 13.56 MHz operating frequency. Finally, the measurement result of a linear class-E power amplifier circuit is obtained to compare and realize the efficiency of the proposed work.

A Modified Design of Class-E Power Amplifier with Balanced FETs and High Output Power for RFID Applications

In Radio Frequency (RF) communication, a Power Amplifier (PA) is used to amplify the signal at the required power level with less utilization of Direct Current (DC) power. The main characteristic of class-E PA is sturdy nonlinearity due to the switching mode action. In this study, a modified design of class-E PA with balanced Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) and high output power for Electronic Article Surveillance (EAS) Radio Frequency Identification (RFID) application is presented. MOSFETs are adjusted to have high output performance of about 80% for RFID-based EAS system. A matching network is also proposed for accurate matching because there are differences in the behavior between RF waves and low frequency waves. The design of a matching network is a tradeoff among the complexity, adjustability, implementation, and bandwidth for the required output power and frequency. The implemented PA is capable of providing 44.8 dBm output power with Power-Added Efficiency (PAE) of 78.5% at 7.7 MHz to 8.7 MHz.

Design, Simulation and Fabrication of Broadband Class-E Power Amplifier Using Double-Reactance Compensation Technique and Second and Third Harmonic Control Circuits

Design, Simulation and Fabrication of Broadband Class-E Power Amplifier Using Double-Reactance Compensation Technique and Second and Third Harmonic Control Circuits

Analysis and design procedure of a mm-Wave Class-E power amplifier

This paper presents a Class-E Power Amplifier (PA) design procedure for operation at mm-Wave frequencies, which accounts for the loss of passive components, ON-resistance (Ron) of the transistor, and its breakdown voltage (VBr). The quality factor of inductors is modeled with equivalent resistors and integrated into time-domain equations for the first time. The proposed procedure is examined for the design of a 24 ​GHz Class-E PA in 130 ​nm CMOS technology and compared with former best-known design recipes in the same technology node. Besides, a simplified design technique is introduced based on Ron-Cout (Cout is the transistor output capacitance) curves of the transistor versus its width, obtained by Harmonic Balance (HB) simulation. By the proposed method, the Figure of Merit (FoM) of the designed PA, including a combination of the output power, efficiency, and maximum drain voltage, is improved significantly (52%) compared to the other procedure outcomes in the literature.

Broadband class-E power amplifier design using tunable output matching network

This paper presents a design of a broadband high-efficiency Class-E power amplifier (PA) with a tunable output matching network (OMN). The OMN contains two main parts: The first part is a Tunable Band-Pass Filter (T-BPF) that determines the center frequency of the PA’s operational bandwidth. And the first part is a fixed matching network that transforms the input impedance of the second part (50 Ω) to an optimum impedance value of transistor’s drain. The tuning process of the BPF is realized using a Varactor Diode Stack. By changing the bias voltage of the varactor diodes, the center frequency of T-BPF can move throughout 1–2.55 GHz bandwidth. The GaN HEMT CGH40010F from Cree has been selected due to its wide bandwidth, high efficiency, and high achievable gain for PA design. Simulation results show an output power of 40–41.5 dBm, Drain Efficiency (DE%) of 57.2–81.2% and transducer power gain of 10–12.5 dB across 1–2.55 GHz (87.3% fractional bandwidth). The proposed design outperforms previous tunable and fixed power amplifiers regarding bandwidth and efficiency.

Design of class-E power amplifier for capacitive power transfer system

High frequency power source is an indispensable part of capacitive power transfer system, and its performance plays an essential role in the overall system. Considering that class-E power amplifier is a prominent switched-mode power amplifier, and its power conversion efficiency can reach nearly 100%, theoretically. In this work, according to the requirements of capacitive power transfer system for power, the high efficiency class-E power amplifier as the AC source of the system has been designed. Firstly, the partial component parameters of class-E power amplifier can be calculated by circuit theory. Secondly, simulation circuits of the class-E power amplifier are designed by ADS software. Finally, an experimental prototype with the designed parameters is built up to verify the theory and simulation results. The experimental results show that the improved class-E power amplifier can reach work efficiency of 91% with 30 W output power, and capacitive power transfer system can achieve transfer efficiency of 76.2% with 25.15 W output power.

Broadband GaN Class-E Power Amplifier for Load Modulated Delta Sigma and 5G Transmitter Applications

The paper presents a design of a broadband high-efficiency class-E power amplifier (PA) for the advanced efficiency enhancement architectures applications. A sequential load pull methodology to design broadband class-E power amplifiers using a packaged gallium nitride power transistor is presented. Two different broadband matching synthesis techniques have been proposed using lumped elements have been presented and implemented in the manuscript. A fourth-order low-pass impedance transformation topology is designed as the output matching network to provide the optimum load reflection coefficients in the targeted bandwidth (1.8–2.7 GHz). A combination of input and output matching network has been proposed in the manuscript to satisfy the given fractional bandwidth requirements. For practical validation, a Wolfspeed (Cree) CGH40025 package transistor has been used. Under continuous wave test condition the fabricated PA showed more than 50% power added efficiency (PAE) with up to 29 W output power for 40% fractional bandwidth from 1.8–2.7 GHz. Furthermore, the proposed broadband Class E PA is deployed in efficiency enhancement architecture like delta-sigma modulation based transmitters. The PA shows more than 48% PAE all over the frequency band when driven with a delta-sigma modulated LTE downlink signal while maintaining high signal quality and PA reliability.

Analysis and design of continuous class-E power amplifier at sub-nominal condition

ABSTRACTThe continuous class-E power amplifier at sub-nominal condition is proposed in this paper. The class-E power amplifier at continuous mode means it can be high efficient on a series matching networks while at sub-nominal condition means it only requires the zero-voltage-switching condition. Comparing with the classical class-E power amplifier, the proposed design method releases two additional design freedoms, which increase the class-E power amplifier’s design flexibility. Also, the proposed continuous class-E power amplifier at sub-nominal condition can perform high efficiency over a broad bandwidth. The performance study of the continuous class-E power amplifier at sub-nominal condition is derived and the design procedure is summarised. The normalised switch voltage and current waveforms are investigated. Furthermore, the influences of different sub-nominal conditions on the power losses of the switch-on resistor and the output power capability are also discussed. A broadband continuous class-E power amplifier based on a Gallium Nitride (GaN) transistor is designed and testified to verify the proposed design methodology. The measurement results show, it can deliver 10–15 W output power with 64–73% power-added efficiency over 1.4–2.8 GHz.

A Class-E Power Amplifier Design Considering MOSFET Nonlinear Drain-to-Source and Nonlinear Gate-to-Drain Capacitances at Any Grading Coefficient

This paper presents theory and analysis for class-E power amplifier considering MOSFET nonlinear gate-to-drain and nonlinear drain-to-source capacitances at any grading coefficient of the MOSFET body junction diode. The nonlinearity degree of a MOSFET parasitic capacitance is determined by the grading coefficient. When the grading coefficient is not considered in design procedure, the switch voltage waveform of the class-E power amplifier does not satisfy the switching conditions, which results in a decrease of the power conversion efficiency. Therefore, the grading coefficient is an important parameter to satisfy the class-E zero-voltage switching (ZVS) and zero-derivative switching (ZDS) conditions. The MOSFET gate-to-drain capacitance is highly nonlinear, and it is more nonlinear than drain-to-source capacitance for most MOSFETs. In some cases, the change in the gate-to-drain capacitance can be as large as 100 times. The results show that this nonlinearity affects the class-E power amplifier properties, such as switch voltage, power output capability, and maximum switch voltage. Therefore, it is necessary to consider the nonlinearity of the gate-to-drain capacitance, along with the drain-to-source capacitance. A design example at 4 MHz operating frequency is also given to describe the design procedure. The ZVS and ZDS conditions are achieved in the obtained switch voltage. The circuit simulation was performed using PSpice software. For verification of the presented theory, a class-E power amplifier is fabricated. The measured results are verified with simulation and theory results.

고효율 무선 전력 전송을 위한 고효율 E급 전력 증폭기 및 공진 코일 설계에 관한 연구

고효율 무선 전력 전송을 위한 고효율 E급 전력 증폭기 및 공진 코일 설계에 관한 연구

5.3 GHz 42% PAE class‐E power amplifier with 532 mW/mm 2 power area density in 180 nm CMOS process

A 5.3 GHz high-efficiency and low-cost class-E power amplifier (PA) implemented in a 180 nm CMOS process is presented. Cascode configuration is utilised in the class-E PA to achieve high efficiency due to its high gain property and low drain-to-source parasitic capacitor. Through the trade-off between inductance and inductor loss, an optimised RF choke inductor for fully integrated class-E PA design can be selected to achieve high efficiency while maintaining compact circuit size. The class-E CMOS PA demonstrates the highest Power Added Efficiency (PAE) of 42% and greatest power area density of 532 mW/mm2 in 0.263 mm2 chip area to date.

Improved Reactance-Compensation Technique for the Design of Wideband Suboptimum Class-E Power Amplifiers

A reactance-compensation technique has been introduced recently for the design of wideband class-E power amplifiers (PAs). With this technique, the load resistance can be transformed to an optimal complex drain impedance in a broad frequency band. One potential problem of this technique is that an additional network is often needed to transform 50 $\Omega$ to the optimum load resistance, which is typically at a lower value. This paper proposes a method to improve the reactance compensation technique. By using the proposed method, the required low-value load resistance is up to four times the original value. This is achieved not by adding more components, but by simply changing the order and values of them. With the proposed method, the additional resistance matching network is no longer needed in many cases, or can be significantly simplified in other cases. To validate the theory, two broadband class-E amplifiers were designed using the original technique and the proposed method, respectively. The performances of the two amplifiers are compared. By using similar complexity of matching networks, the PA designed using the original method can achieve better than 70% power-added efficiency for a fractional bandwidth of 42%. The PA designed using the proposed method can achieve above 70% efficiency for a bandwidth of 51%. The proposed method can be used in the design of many other types of amplifiers.

Performance Limits, Design and Implementation of mm-Wave SiGe HBT Class-E and Stacked Class-E Power Amplifiers

<?Pub Dtl=""?> Design equations and performance limits of Class-E power amplifiers at mm-waves, including the limitations imposed by active and passive devices in a given technology, are presented in this paper. A beyond nominal breakdown voltage Class-E design methodology for SiGe HBT power amplifiers is proposed to generate high output power while maintaining high Class-E efficiency. A mm-wave SiGe stacked Class-E architecture is also introduced to increase the overall voltage swing, with each series stacked device operating in the beyond nominal breakdown mode. The mm-wave beyond <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$BV_{\rm CEO}$</tex></formula> operation of SiGe HBTs has been demonstrated experimentally in an integrated 45 GHz Class-E power amplifier fabricated in a 0.13 µm SiGe BiCMOS process with 20 dBm measured output power at 31.5% peak power-added efficiency (PAE). The series stacking of mm-wave Class-E power amplifier concept is also verified by fabricating double-stacked and triple-stacked SiGe HBT power amplifiers in 0.13 µm SiGe BiCMOS process which demonstrate a measured output power of 23.4 dBm at 41 GHz with peak PAE of 34.9%. High power, highly efficient, switching power amplifier unit cells presented in this paper can facilitate realization of efficient Watt-level mm-wave digital polar transmitters.

Design of class-E power amplifier for zero-current switching operation with MOSFET nonlinear output parasitic capacitance

The subnominal condition is defined as only the zero-current switching (ZCS) condition is satisfied. On the other hand, as the operating switching frequency increases, the effect of the MOSFET nonlinear output parasitic capacitance increases. This article introduced the design expressions with the analytical approaches for the design of the class-E power amplifier with a shunt inductor at the subnominal condition, taking into account the MOSFET nonlinear drain-to-source capacitance. The element's values for achieving the subnominal condition are expressed as a function of the phase shift between the input and output voltage. Moreover, the MOSFET nonlinear drain-to-source capacitance affects the switch-current waveform. Therefore, the switch-current waveform does not satisfy the class-E ZCS conditions if the nonlinear effect of the MOSFET output parasitic capacitance ignored. Using the class-E subnominal operation, the degree of the design freedom of the class-E power amplifier is increased by one. The maximum output power along with the increment of the operating frequency at the subnominal condition is obtained. A circuit design example using the proposed design procedure of the class-E power amplifier with ZCS condition is given. The waveforms obtained from the laboratory measurements showed the quantitative agreements with PSpice simulations that proved the usefulness and effectiveness of our proposed design expressions. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:801–808, 2014

(Invited) An X-Band Class-E Power Amplifier with MEMS Output Impedance Tuner

This paper presents the design, fabrication and measurements of a hybrid X-band class-E power amplifier with a MEMS output tuner that enables the power amplifier to operate at optimum efficiency and output power level despite the fabrication uncertainties/tolerances of the device and circuit. The tuner is implemented with two 2.8 : 1 analog MEMS varactors and covers an impedance range of resistance between 10 to 30 Ω and reactance of -3 to -9 Ω. The designed PA delivers 605 mW output power with power added efficiency of 52% at 10.5 GHz.

Design of high PAE class-E power amplifier for wireless power transmission

Design of high PAE class-E power amplifier for wireless power transmission

Analysis and Design of Class-E Power Amplifier With MOSFET Parasitic Linear and Nonlinear Capacitances at Any Duty Ratio

This paper presents analytical expressions for the class-E power amplifier with MOSFET linear gate-to-drain and nonlinear drain-to-source parasitic capacitances at any duty ratio. The maximum operating frequency, output power capability, and element values as functions of the duty ratio are obtained. The element values are directly dependent upon the selection of duty ratio and require a careful duty ratio selection to minimize component power losses and to maximize the total efficiency. Two design examples at 25 and 9 W output power at 4-MHz operating frequency along with the PSpice-simulation and experimental waveforms are presented. It is shown from the derived expressions that the slope of the voltage across the MOSFET gate-to-drain parasitic capacitance during the switch-off state as a function of the duty ratio affects the switch-voltage waveform. Therefore, it is possible to achieve the required peak switch voltage and the class-E ZVS/ZVDS conditions simultaneously by adjusting the duty ratio. The theoretical results and PSpice simulations agreed with experimental results quantitatively, which shows the validity of the presented analysis.

Design and Analysis of Class-E Power Amplifier for Wired &amp; Wireless Systems

In this research article, an advanced class-E Power Amplifier (PA) working at center frequency 1842.5MHz with 75MHz bandwidth is proposed. The class E type power amplifier is premeditated and realized using 0.35µm CMOS technological file in ADS. The proposed class E power amplifier provides low return loss, Signal and Noise Ratio of 47.5dB, low noise figure of 1.434dB and PAE of 69.3%.

Design of Efficient Class-E Power Amplifiers for Short-Distance Communications

This paper presents a new Class-E power amplifier (PA) with a π-matching output network. The PA is targeted at low output power wireless applications. Analytical formulae are derived to aid the PA design, characterization and optimization. A fully integrated 2.4-GHz PA for short distance communications has been implemented in 0.13 μm CMOS technology to verify the proposed design method. The measured output power levels vary from - 3.2 to 5.7 dBm while achieving maximum overall efficiency of 55%.