Many-particle charged-particle plasma simulations using spatial meshes for the electromagnetic field solutions, particle-in-cell (PIC) merged with Monte Carlo collision (MCC) calculations, are coming into wide use for application to partially ionized gases. The author emphasizes the development of PIC computer experiments since the 1950s starting with one-dimensional (1-D) charged-sheet models, the addition of the mesh, and fast direct Poisson equation solvers for 2-D and 3-D. Details are provided for adding the collisions between the charged particles and neutral atoms. The result is many-particle simulations with many of the features met in low-temperature collision plasmas; for example, with applications to plasma-assisted materials processing, but also related to warmer plasmas at the edges of magnetized fusion plasmas. >

Particle-in-Cell Charged Particle Simulations, plus Monte Carlo Collisions with Neutral Atoms, PIC-MCC

This timely second edition has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices.

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GaN Transistors for Efficient Power Conversion

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

A novel methodology for designing high-frequency broadband harmonic-tuned power amplifiers (PAs) is presented in this paper. Specifically, a hybrid PA mode, transferring between continuous inverse Class-F and continuous Class-F, is for the first time employed to design PAs with optimal performance over more than-an-octave bandwidth. A GaN PA is designed and realized based on this mode-transferring operation using a three-stage transmission-line-based low-pass matching network. Simulation and experimental results show that an in-band PA-mode transferring between continuous Class- F-1 and continuous Class-F is successfully performed. The implemented PA achieves a measured 87% bandwidth from 1.3 to 3.3 GHz, while exhibiting a state-of-the-art performance of >;10-dB gain, 60%-84% efficiency, and 10-W output power throughout this band. Furthermore, modulated evaluation is carried out using a 300-kHz bandwidth 16-quadrature amplitude-modulation signal. Good linearity performance is measured with adjacent channel power ratio from -20 to -35 dBc and an error vector magnitude of 4%-9% over the entire bandwidth.

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Design of Broadband Highly Efficient Harmonic-Tuned Power Amplifier Using In-Band Continuous Class- ${\hbox{F}}^{-1}/{\hbox{F}}$ Mode Transferring

A novel power amplifier (PA) architecture, the Load Modulated Balanced PA (LMBA), is presented. The LMBA is able to modulate the impedance seen by a pair of RF power transistors in a quadrature balanced configuration, by varying the amplitude and phase of an external control signal. This enables power and efficiency to be optimized dynamically at specific power backoff levels and frequencies. Unlike the Doherty PA, the load seen by the active devices can be modulated upwards or downwards, both resistively and reactively, with minimal loss of power combination efficiency. The LMBA is presented as a potentially disruptive technique which enables any specific amplifier characteristic to be controlled dynamically over wide signal amplitude and frequency ranges.

An Efficient Broadband Reconfigurable Power Amplifier Using Active Load Modulation

A new methodology for designing and implementing high-efficiency broadband Class-E power amplifiers (PAs) using high-order low-pass filter-prototype is proposed in this paper. A GaN transistor is used in this work, which is carefully modeled and characterized to prescribe the optimal output impedance for the broadband Class-E operation. A sixth-order low-pass filter-matching network is designed and implemented for the output matching, which provides optimized fundamental and harmonic impedances within an octave bandwidth (L-band). Simulation and experimental results show that an optimal Class-E PA is realized from 1.2 to 2 GHz (50%) with a measured efficiency of 80%-89%, which is the highest reported today for such a bandwidth. An overall PA bandwidth of 0.9-2.2 GHz (84%) is measured with 10-20-W output power, 10-13-dB gain, and 63%-89% efficiency throughout the band. Furthermore, the Class-E PA is characterized through measurements using constant-envelop global system for mobile communications signals, indicating a favorable adjacent channel power ratio from -40 to -50 dBc within the entire bandwidth.

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Design of Highly Efficient Broadband Class-E Power Amplifier Using Synthesized Low-Pass Matching Networks

This paper presents a novel adaptive power amplifier (PA) architecture for performing dynamic-load-modulation. For the first time, a dynamically-load-modulated PA design that achieves octave bandwidth, high power and high efficiency simultaneously is experimentally demonstrated. This PA design is based on a commercial GaN HEMT. The output matching scheme incorporates a broadband static matching for high-efficiency at the maximum power level and a wideband dynamic matching for efficiency enhancement at power back-offs. The impedance and frequency tunability is realized using silicon diode varactors with a very high breakdown voltage of 90 V. Experimental results show that a dynamic-load-modulation from maximum power to 10-dB back-off is achieved from 1 to 1.9 GHz, with a measured performance of ≈10-W peak power, ≈10-dB gain, 64%-79% peak-power efficiency, and 30%-45% efficiency at 10-dB power back-off throughout this band.

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Design of Adaptive Highly Efficient GaN Power Amplifier for Octave-Bandwidth Application and Dynamic Load Modulation

This paper reports the first co-design configuration of a power amplifier (PA) in cascade with a high- Q bandpass filter. By matching the filter's input port directly to the transistor's drain node, the conventional output matching network (OMN) of a PA is entirely eliminated. This leads to smaller size/volume, minimized loss, and enhanced overall performance. To enable this co-design method, the matching-filter synthesis theory is proposed and investigated in detail in this paper. Based on this theory, a 3% bandwidth (centered at 3.03 GHz) two-pole filter, implemented using high- Q evanescent-mode cavity resonators, is designed as the PA OMN to provide optimized fundamental and harmonic impedances for a commercial 10-W GaN transistor. Simulation and measured results show that the co-designed PA-filter module yields a desired Chybeshev filter behavior while maintaining excellent PA performance in the passband with 72% efficiency, 10-W output power, >10-dB gain, and 60-dBm output third-order intercept point. This co-designed module experimentally presents a 8% higher overall efficiency compared to a control group developed using a conventional independent PA and filter, which further validates the effectiveness of this method.

Co-Design of Highly Efficient Power Amplifier and High- $Q$ Output Bandpass Filter

This letter presents the first high-frequency, multi-harmonic-controlled (> 3), Class-F power amplifier (PA) implemented with a packaged GaN transistor. For PA design at high frequencies, parasitics of a packaged transistor significantly increase the difficulty of harmonic manipulation, compared to low-frequency cases. To overcome this issue, we propose a novel design methodology based on a three-stage, low-pass, output matching network, which is realized with transmission lines. This network provides optimal fundamental impedance and allows harmonic control up to the fourth order to enable an efficient Class-F behavior. The implemented PA exhibits a state-of-the-art performance at 3.1 GHz with a 82% PAE, 15 dB gain, and 10 W output power, indicating a clear advantage of this method over the conventional ones with extra parasitic compensators.

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Kenle Chen

Papers

Design of Highly Efficient Broadband Class-E Power Amplifier Using Synthesized Low-Pass Matching Networks

Design of Broadband Highly Efficient Harmonic-Tuned Power Amplifier Using In-Band Continuous Class- ${\hbox{F}}^{-1}/{\hbox{F}}$ Mode Transferring

Design of Adaptive Highly Efficient GaN Power Amplifier for Octave-Bandwidth Application and Dynamic Load Modulation

Co-Design of Highly Efficient Power Amplifier and High- $Q$ Output Bandpass Filter

A 3.1-GHz Class-F Power Amplifier With 82% Power-Added-Efficiency