Power Amplifier Module Research Articles

Class iCGF–1 Mode Power Amplifier for Enhancing the Linearity of the Traditional Continuous Class F–1 Mode

ABSTRACTIn this paper, the iCGF−1 mode is proposed to compensate the amplitude‐to‐amplitude modulation (AM/AM) distortion of the traditional continuous class F−1 mode while maintaining the high efficiency. The AM/AM profile of the iCGF−1 mode is mathematically expressed simultaneously as a function of the input nonlinearity parameter and conduction angle , which makes the iCGF−1 mode more flexible in controlling the AM/AM profile. The first inflection point of the AM/AM profile can be moved to a higher output power level through theoretical deduction by adjusting the second harmonic source impedance and gate bias voltage to increase the values of and . This flattens the AM/AM profile while the efficiency profile remains almost the same as that of the traditional continuous class F−1 mode. The performance of the iCGF−1 mode is verified through simulation and experimental measurements. The iCGF−1 PA is fabricated with CGH40010F and has a frequency range of 2–2.6 GHz. The drain efficiency is 70.1%–77.9%, and the output power is 41.1–41.7 dBm. The linearity is tested with a 100 MHz 5G NR signal (the peak average power ratio (PAPR) is 8.5 dB) at 2.3 GHz. The worst adjacent channel power ratio (ACPR) is −32.3 dBc without digital predistortion (DPD) and −52.1 dBc with DPD. The results show that the iCGF−1 mode has successfully compensated the AM/AM distortion of the traditional continuous class F mode and maintaining high efficiency.

Switching-mode audio amplifier based on a ΔΣ A/D converter

The article describes the design and implementation of a modular hardware platform intended for testing and measuring various configurations of switching-mode audio amplifiers based on sigma-delta modulation. Two single-channel power amplifier modules were designed and manufactured, along with a stereophonic module serving as the basic source of modulated signals. Additionally, measurements were conducted on the fundamental parameters of the completed amplifier, such as harmonic distortion level, dynamic range, and output power. The developed platform serves as a foundation for modifications and further advancement in the technology of building switching-mode audio amplifiers.

A Compact GaN Power Amplifier Module for New Generation Cellular Basestations

This paper presents a compact class-AB Power Amplifier Module (PAM) designed for new generation massive Multiple Input Multiple Output (MiMo) cellular base stations. The module is designed at the center frequency of 3.5GHz targeting Long Term Evolution (LTE) and 5G New Radio (NR) bands. The module is a hybrid design that incorporates a Gallium Nitride (GaN) High Mobility-Electron Transistor (HEMT) die, discrete components-based input, and output matching networks. The entire design is realized on an 8.5 x 5.2 mm, 2-layer Rogers4003C substrate. The module is assembled on a PCB as an open-top for post-characterization tuning. The small signal and large signal measurements are in quite good agreement. The measurement results show that the amplifier is unconditionally stable, the input return loss is 12.2 dB, the output return loss is 7.7 dB, and the small signal gain is 13.4 dB. The saturated output power is 33.3 dBm with a Power Added Efficiency of 20.1%. The small signal gain drops to 11.2 dB at around 22 dBm of input power due to GaN technology’s intrinsic soft compression characteristics.

Input‐harmonic manipulated wideband high‐efficiency series of continuous mode power amplifier

SummaryIn this paper, a systematic research of the effects of second source harmonics caused by gate‐source capacitance in the design of a series of continuous mode (SCM) power amplifiers (PAs) is first presented. The research results show that, compared to the conventional SCMs that require the input second harmonic to be short circuited, SCMs under the impact of input nonlinearity have a more flexible input second harmonic manipulation space, and to further improve and maintain the performance of PAs in wideband operations, a new impedance design space is explored through analysis. For practical validation, SCMs PA considering the effects of the input nonlinearity is designed and fabricated with a 10‐W gallium nitride (GaN) device, acquiring 39.1–42 dBm output power and 60.6–71.5% drain efficiency (DE) performance at a 3 dB gain compression level operating over the 0.5–3.5 GHz frequency range with a relative bandwidth of 150%.

Design and development of efficient and compact 20 kW 325MHz solid-state amplifier for superconducting accelerator applications.

An efficient and compact, 20 kW solid-state power amplifier (SSA) at 325MHz has been designed and developed in-house, using single stage combining. It comprises of 24 nos. of 1 kW power amplifier (PA) modules, a 24-way Wilkinson power combiner and divider, and other peripheral systems. The typical gain and conversion efficiency of the PA modules at 1.0 kW output is 21.7 dB and 66.6%, respectively. It is demonstrated that overall power gain and AC to RF efficiency of this SSA at 20 kW is 88.5 dB and 54.8%, respectively, which matches closely with the design estimates. The harmonic content in the RF output is < -40 dBc for all the harmonics. The results of the Monte Carlo simulation are also presented, showing lower bound on combining efficiency with a degree of confidence if magnitude and phase data for 24 inputs are randomly chosen from a normal distribution's pre-defined interval. The salient features of this SSA include power density of 12.7 kW/m3, AC to RF efficiency of 54.8% at 20 kW, and guaranteed output of 20 kW with one failed PA module and 18.1 kW under two failed PA modules condition.

A 6-/12-dB back-off reconfigurable Doherty-like load modulated balanced amplifier with compact area and wide bandwidth

This article presents a Doherty-like Reconfigurable Load Modulated Power Amplifier (R-LMBA) topology, which enables a broadband 6-/12-dB power back-off (PBO) reconfiguration by rearranging the bias voltages of the sub-amplifiers with compact area. The proposed R-LMBA guarantees proper phase differences among the three sub-PAs across the entire operating frequency band without the need for a bulky phase shifter that is adopted in conventional LMBAs. The design equations for the R-LMBA are proposed and analyzed in detail. A proof-of-concept PA has been designed in 0.1 μm GaAs pHEMT process to verify the proposed concept. In Mode-1, from 30 to 40 GHz, it achieves saturated output power (Psat) of 27.7–29.1 dBm with peak power added efficiency (PAE) of 28.5–34.4%, and 16.8–22.1% PAE at 6-dB PBO with its best 1.29 × efficiency enhancement over a Class-B counterpart. In Mode-2, it exhibits 28 dBm Psat with 30% peak PAE, and a PAE of 25%/13.6% at 6-/12-dB PBO, which is 1.67 × /1.81 × over an ideal Class-B PA. Besides, in Mode-1/-2, the PA demonstrates 21.3/20.3 dBm average output power (Pavg) and 17.9%/22.1% average PAE (PAEavg) with −28.1/-23.8 dB error vector magnitude (EVM) and −29.1/-25.9 dBc adjacent channel leakage ratio (ACLR) under 6-Gb/s 64-QAM modulated signal at 35 GHz.

Non-Linear Simulation by Harmonic Balance Techniques of Load Modulated Power Amplifier Driven by Random Modulated Signals

The simulation of the steady state and the non-linear stability of a load modulated power amplifier (LMPA) driven by a random modulated generator, fully performed in the frequency domain by harmonic balance (HB) techniques, is presented. The non-linear microwave circuit and the driving pseudo-random modulated (PRM) generator are integrally defined in the frequency domain. The simulation is implemented and performed using commercially available circuit simulation software. The demodulation of the output signal of the LMPA is implemented with optimally matched filters as software-defined demodulation. The simulated dynamic results of a Quasi-MMIC GaN Doherty power amplifier (DPA) are shown and compared to the measured results with a 16-QAM driving signal at 10 MS/s. The time-domain measurement allows the validation of the new simulation technique through the comparison of both the measured and the simulated error vector magnitude (EVM), the left and right adjacent channel power ratios (ACPRs) versus the average output power. This new simulation is then called pseudo-random modulated harmonic balance (PRM-HB) simulation. The full PRM-HB simulation of an LMPA driven by a random modulated signal, performed in the frequency domain at the design circuit level, results in an advanced simulation tool in the frame of the design of RF circuits and subsystems for telecommunication applications.

N77 Radio Frequency Power Amplifier Module for 5G New-Radio High-Power User Equipment Mobile Handset Applications

This paper presents a highly efficient 5G New-Radio (NR) RF power amplifier module (PAM). The n77 PAM consists of a high-voltage differential-topology 2 μm GaAs HBT power amplifier, a CMOS controller, a silicon-on-insulator (SOI) switch, an integrated passive device (IPD) bandpass filter, a low-noise amplifier (LNA), and a bi-directional coupler. This PAM generates a saturation output power of 32.7 dBm including the loss of the SOI switch and output filter. The designed n77 PAM is tested with a commercial envelope tracker IC (ET-IC). The designed PAM with an ET-IC achieves an ACLR of −37 dBc at a 27 dBm output power with a DFT-s-OFDM QPSK 100 MHz NR signal and saves a dc power consumption of 950 mW compared to the APT mode. For the CP-OFDM 256QAM with the most stringent EVM requirements, it achieves an EVM of 1.22% at 23 dBm and saves 640 mW compared to the APT mode.

An improved impedance space for extended hybrid continuous mode power amplifiers

AbstractExtended hybrid continuous mode expands the design bandwidth of the power amplifier (PA) by sacrificing drain efficiency. To balance the performance of drain efficiency and bandwidth, this letter limits the range of relevant parameters of its impedance space through theoretical analysis. An improved high‐efficiency load impedance space is proposed. Through the improved high‐efficiency impedance space, a PA operating at 0.8–2.2 GHz is designed, with a drain efficiency of more than 55% and an output power of more than 38.2 dBm, which verifies the design goals of broadband and high efficiency.

PA-Net: A phase attention network fusing venous and arterial phase features of CT images for liver tumor segmentation

Background and ObjectiveLiver cancer seriously threatens human health. In clinical diagnosis, contrast-enhanced computed tomography (CECT) images provide important supplementary information for accurate liver tumor segmentation. However, most of the existing methods of liver tumor automatic segmentation focus only on single-phase image features. And the existing multi-modal methods have limited segmentation effect due to the redundancy of fusion features. In addition, the spatial misalignment of multi-phase images causes feature interference. MethodsIn this paper, we propose a phase attention network (PA-Net) to adequately aggregate multi-phase information of CT images and improve segmentation performance for liver tumors. Specifically, we design a PA module to generate attention weight maps voxel by voxel to efficiently fuse multi-phase CT images features to avoid feature redundancy. In order to solve the problem of feature interference in the multi-phase image segmentation task, we design a new learning strategy and prove its effectiveness experimentally. ResultsWe conduct comparative experiments on the in-house clinical dataset and achieve the SOTA segmentation performance on multi-phase methods. In addition, our method has improved the mean dice score by 3.3% compared with the single-phase method based on nnUNet, and our learning strategy has improved the mean dice score by 1.51% compared with the ML strategy. ConclusionThe experimental results show that our method is superior to the existing multi-phase liver tumor segmentation method, and provides a scheme for dealing with missing modalities in multi-modal tasks. In addition, our proposed learning strategy makes more effective use of arterial phase image information and is proven to be the most effective in liver tumor segmentation tasks using thick-layer CT images. The source code is released on (https://github.com/Houjunfeng203934/PA-Net).

Authors’ Response to Comments on “Investigation of a Class-J Mode Power Amplifier in Presence of a Second-Harmonic Voltage at the Gate Node of the Transistor”

Authors’ Response to Comments on “Investigation of a Class-J Mode Power Amplifier in Presence of a Second-Harmonic Voltage at the Gate Node of the Transistor”

Comments on “Investigation of a Class-J Mode Power Amplifier in Presence of a Second-Harmonic Voltage at the Gate Node of the Transistor”

Comments on “Investigation of a Class-J Mode Power Amplifier in Presence of a Second-Harmonic Voltage at the Gate Node of the Transistor”

Uniform/Selective Heating Microwave Oven Using High Efficiency GaN-on-GaN HEMT Power Amplifier

A high-efficiency uniform/selective heating microwave oven was developed. Because the power amplifier requires high-efficiency characteristics to function as a microwave source, a free-standing Gallium Nitride (GaN) substrate was applied in this study. By applying a harmonic tuning circuit, an output power of 71 W and PAE of 73% were achieved in pulsed operation, and an output power of 63 W and PAE of 69% were achieved in CW operation. Moreover, we fabricated a prototype PA module that consists of an oscillator, a driver amplifier, PA, and other RF circuits. The output power was controlled by pulse width modulation to maintain high efficiency regardless of output power. We evaluated the arrangement of antenna polarizations to isolate each antenna. By suppressing the interference of output from adjacent antennas, it is possible to irradiate the object on the top surface of the antenna, thereby demonstrating heating characteristics with small temperature unevenness. The prototype microwave oven successfully demonstrated uniform/selective heating.

A Sub-THz Waveguide Magic-T With Coplanar Ports for Power Combination Applications

In this article, a compact waveguide magic-T (WMT) with four coplanar ports is presented for sub-THz power combination applications. In the WMT, simple and robust geometries, i.e. trapezoidal irises, cuboid-shaped ridge, and waveguide step, are employed to ease manufacturing difficulties at sub-THz frequencies. Thereinto, the trapezoidal irises replace the traditional multiple steps or long chamfers to simplify the waveguide transformer and shorten the path, the waveguide step widens the available bandwidth, and the cuboid-shaped ridge reduces the difference-port reflection and acts as a coupling probe for the sum-port to improve isolation. Moreover, a bed of nails is applied to the waveguide splitting-plane for electromagnetic (EM) leakage suppression and assembly convenience. To verify this WMT, a WR-4 band (170-260 GHz) prototype is fabricated and measured, showing an average combination efficiency of 92.2% within 175-255 GHz (37.2%-bandwidth). Then, the WMT is applied to a two-way combined solid-state power amplifier (SSPA) module. Thereinto, a contactless E-plane waveguide transition with unprecedented L-shaped chock grooves (LSCGs) is presented for waveguide system interconnection. In power measurement, the power combined module produces a maximum power output of 76.6-mW @ 216-GHz.

A Wideband and Highly Efficient Circulator Load Modulated Power Amplifier Architecture

A complete theoretical analysis is presented for a highly efficient power amplifier (PA) architecture based on a non-reciprocal combiner. The architecture consists of two amplifier branches and a microwave circulator acting as the output combiner, referred to as the circulator load-modulated amplifier (CLMA). The continuous-mode (CM) design technique has been further exploited for the CLMA to demonstrate the wideband capabilities of the architecture. The analysis reveals that the CLMA performs active load modulation to maintain high PA efficiency performance across a wide bandwidth and large output power dynamic range. As a proof of concept, a CLMA demonstrator circuit based on gallium nitride (GaN) transistors and a microwave circulator, is designed and characterized with continuous-wave and modulated-signal measurements. The implemented CLMA prototype circuit experimentally demonstrates Doherty-like efficiency enhancement over a large bandwidth covering 2.1 to 3.5 GHz. In measurements, the prototype exhibits a drain efficiency of 46.7-57.5% at peak output power and 35.6-50.6% at 7-dB output power back-off level, within the design bandwidth. When tested with a 60-MHz multi-carrier orthogonal frequency-division multiplexing (OFDM) signal having a 7-dB peak-to-average power ratio (PAPR), an average efficiency of 48.5% with better than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 47.5-dBc adjacent channel leakage ratio (ACLR) is achieved after applying digital pre-distortion (DPD).

Study on the Ku band Solid-State Power Amplifier(SSPA) through the 40 W-grade High Power MMIC Development and the Combination of High Power Modules

In this paper, to substitute the existing TWTA(Travailing Wave Tube Amplifier) component in small radar system, we developed the Ku band SSPA(Solid-State Power Amplifier) based on the fabrication of power MMIC (Monolithic Microwave Integrated Circuit) chips. For the development of the 500 W SSPA, the 40 W-grade power MMIC was designed by ADS(Advanced Design System) at Keysight company with UMS GH015 library, and was processed by UMS foundry service. And 70 W main power modules were achieved the 2-way T-junction combiner method by using the 40 W-grade power MMICs. Finally, the 500 W SSPA was fabricated by the wave guide type power divider between the drive power amplifier and power modules, and power combiner with same type between power modules and output port. The electrical properties of this SSPA had 504 W output power, -58.11 dBc spurious, 1.74 °/us phase variation, and -143 dBm/Hz noise level.

Over Octave Hybrid Continuous Modes Power Amplifier Design Based on Modified Real Frequency Technique

In this paper, a design method for an over octave hybrid continuous mode power amplifier (PA) based on modified real frequency technique (MRFT) is proposed. The extended continuous class-F/F-1 modes greatly expand the design space, which provides the possibility of over octave design, the optimal impedances at internal current-generator (I-Gen) plane and package plane are investigated. Then a novel broadband matching network based on MRFT is presented for impedance match. To verify the proposed methodology, an over octave PA with radial stub is fabricated and measured. The PA achieves a bandwidth of 133% from 0.8 GHz to 4 GHz, over this frequency range, the drain efficiency is 58.3-68.7% and largesignal gain is greater than 9.6 dB.

An 8.1-W, 50.9% efficient continuous Class-F mode power amplifier developed using 0.25-μm GaN/SiC technology for 5G NR n79 band

This letter presents an integrated 5G NR n79-band power amplifier with high power and efficiency that was fabricated using WIN Semiconductors’ 0.25-mm GaN/SiC technology. The stability and linearity issues of the PA is thoroughly considered. High efficiency and broadband operation were achieved using a continuous Class-F mode output matching network. This two-stage PA had a power gain, 3-dB power bandwidth, saturation power, and peak power-added efficiency of 20.4 dB, 3.6-5.4 GHz, 39.1 dBm, and 50.9%, respectively. Its average output power was 33.3 dBm under an error vector magnitude requirement of 3.5% for a 5G NR FR1 256-QAM 100-MHz-bandwidth modulated signal with a frequency of 3.7-5.0 GHz.

Reflection power suppression for solid state amplifiers with combiner optimization.

The application of high-power solid state amplifiers (SSAs) in accelerator facilities is increasing, and equipment failure caused by reflected power is the main risk to their long-term operation. High-power SSAs often comprise multiple power amplifier modules. Full power reflection is more likely to damage the modules in SSAs if the amplitudes of the modules are unequal. Optimization of the power combiners is an effective means for improving the stability of SSAs under high power reflection. This study analyzes the mechanisms and conditions of reflected power generation using the scattering parameters of the combiner and proposes an optimization scheme for the combiner. The simulation and experimental results show that some modules may receive reflected power as high as nearly four times the rated power of one module when the SSA meets certain conditions, which could damage the modules. The maximum reflected power can be effectively reduced and the anti-reflection ability of SSAs can be improved by optimizing the combiner parameters to suppress the maximum reflected power.

THE COMPUTER MODELING OF CLASS -D AND -DE SWITCHING-MODE POWER AMPLIFIERS FOR VHF DIGITAL RADIO BROADCAST EQUIPMENT

Currently the transition to digital VHF radio broadcasting is being discussed more and more in different countries, which requires the design of new radio broadcast equipment devices. In classical method of amplifying the power of complex radio signals with a variable envelope, the new broadcast equipment will lose significantly to the existing broadcast equipment with frequency-modulated signal in many energy parameters. The most the promising ways to build high-efficiency broadcast equipment devices of complex radio signals with amplitude-phase modulation and high peak-factor are synthetic methods of linear amplification of radio frequency power (for example, basing on the scheme of L. Kahn) by using high-efficiency switching-mode circuits of powerful amplification. The present state of development of powerful radio-frequency transistors allows to assume that in the near future in the VHF-band switching-mode power amplifiers of Class -D and -F, which will be suitable for building digital radio broadcast equipment with the polar architecture of L. Kahn, will be everywhere used. These switching-mode amplifiers, in contrast to higher-frequency Class-E circuits, supply more steady characteristics in the frequency band. But when developing such broadcast equipment, it is also reasonable to deal with modified switching-mode power amplifiers of the Class -DE and -FE. The article deals with the questions of the computer modeling of switching- mode power amplifiers of Class -D and -DE in relation to the design of VHF radio broadcast equipment.