Microwave Power Amplifier Design Research Articles

A computational analysis of the impact of thin undoped channels in surface-related current collapse of AlGaN/GaN HEMTs

Abstract This study provides an insight into the impact of thin purely undoped GaN channel thickness (t ch) on surface-related trapping effects in AlGaN/GaN high electron mobility transistors. Our TCAD study suggests that in cases where parasitic gate leakage is the driving trapping mechanism that promotes the injection of electrons from the Schottky gate contact into surface states, this effect can be alleviated by reducing t ch of the undoped GaN channel. We show that by decreasing t ch from 130 to 10 nm, devices exhibit a reduction in gate-related current collapse under the specific class-B RF operating bias conditions as a consequence of a substantial decrease in the off-state gate leakage with reducing t ch. Large-signal simulations revealed an increase by 3 W mm−1 and about 12% output power and power-added efficiency due to the decrease of gate-related collapse. This work, for the first time, highlights the role of a proper purely undoped GaN t ch selection to alleviate gate-related surface trapping in the design of GaN-based microwave power amplifiers.

A large-signal scaling model of high-power GaN microwave device

With the rapid development of wireless communications, GaN HEMT, which has various advantages of high power density, high electron mobility, and high breakdown threshold, receiving increasing attention. Microwave power amplifiers based on GaN HEMTs are widely used in many fields, such as communication, medical, and detection instruments. In the accurate design of GaN microwave power amplifiers, reliable RF large signal model is vitally important. In this paper, a scalable large-signal model based on EEHEMT model is proposed to describe the properties of multifinger AlGaN/GaN high electron mobility transistor (HEMT) accurately. A series of scaling rules is established for the intrinsic parameters of the device, including drain-source current <i>I</i><sub>ds</sub>, input capacitance <i>C</i><sub>gs</sub> and <i>C</i><sub>gd</sub>, which take into account both the gate width of a single finger and the number of gate fingers. With the proposed scalable large-signal model, the performance of the L-band GaN high-efficiency power amplifier with a gate length of 14.4 mm is analyzed. This amplifier demonstrates outstanding performance, with the output power reaching to 46.5 dBm and the drain efficiency arriving at over 70% of the frequency range from 1120 MHz to 1340 MHz. Good agreement between the simulations and experiments is achieved, demonstrating the excellent accuracy of the proposed model. Moreover, the proposed model can further predict the performance of high-order harmonics, providing an effective tool for designing advanced high-power and high-efficiency microwave power amplifiers. Certainly, the EEHEMT model fails to characterize the dynamical behavior induced by trapping and self-heating effects. Thus, for further consideration, scaling models for the thermal resistance and heat capacity need further investigating to broaden the application scope of the proposed model in the case of continuous waves.

Design of a dual-band microwave power amplifier for wireless communications

In this paper, we present a design of a concurrent dual-band power amplifier operating at 5.8 GHz and 9.4 GHz employing a MMIC technology for wireless communications. The active device used is a 0.25 µm AlGaN/GaN HEMT from WIN Semiconductor, Taiwan. The design goal is to achieve the high-efficiency while still retaining other important metrics including output power and power Gain at concurrent dual frequency bands. The performance of the designed amplifier is evaluated at both small and large signal levels through theoretical analyses and simulation using a Keysight ADS simulator. The developed dual-band amplifier delivered a 47% PAE with 30.5 dBm output power and 12.5 Gain at 5.8 GHz, and a 37% PAE with 30.2 dBm output power and 12.2 Gain at 9.4 GHz.

Design of a High-Efficiency GaN High-Electron Mobility Transistor Microwave Power Amplifier

This study presents a design procedure to obtain high-efficiency for microwave power amplifier. The designed amplifier uses a GaN high electron mobility transistor as an active device. Matching networks including input and output networks are realized using Megtron6 substrate microstrip lines. The designed amplifier operates at 2.1 GHz band. The simulated results show that the amplifier delivers a maximum power-added efficiency of 73.2% at output power and power gain of 47.8 dBm and 13.8 dB, respectively. This promising designed performance makes this amplifier to be an excellent candidate for use in modern wireless communication systems like radar, mobile network, and satellite communications.

On the design of class-J microwave power amplifier

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.

On the Design of Class-J Microwave Power Amplifier

Abstract 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 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.

Optimized power simulation of AlGaN/GaN HEMT for continuous wave and pulse applications**Project supported by the National Natural Science Foundation of China (No. 61204086).

An optimized modeling method of 8 × 100 μm AlGaN/GaN-based high electron mobility transistor (HEMT) for accurate continuous wave (CW) and pulsed power simulations is proposed. Since the self-heating effect can occur during the continuous operation, the power gain from the continuous operation significantly decreases when compared to a pulsed power operation. This paper extracts power performances of different device models from different quiescent biases of pulsed current–voltage (I–V) measurements and compared them in order to determine the most suitable device model for CW and pulse RF microwave power amplifier design. The simulated output power and gain results of the models at Vgs = −3.5 V, Vds = 30 V with a frequency of 9.6 GHz are presented.

X-parameter measurement on a GaN HEMT device: Complexity reduction study of load-pull characterization test setup

Characterization of power transistors is an indispensable step in the design of radio frequency and microwave power amplifiers. A full harmonic load-pull measurement setup is normally required for the accurate and comprehensive characterization of RF power transistors. The setup is usually highly complex, leading to a relatively high hardware cost and low measurement throughput. This paper presents X-parameter measurement on a gallium nitride (GaN) high-electron-mobility transistor and studies the potential of utilizing an X-parameter-based modeling technique to highly reduce the complexity of the harmonic load-pull measurement setup for transistor characterization. During the X-parameter measurement and characterization, load impedance of the device is tuned and controlled only at the fundamental frequency and is left uncontrolled at other higher harmonics. However, it proves preliminarily that the extracted X-parameters can still predict the behavior of the device with moderate to high accuracy, when the load impedance is tuned up to the third-order harmonic frequency. It means that a fundamental-only load-pull test setup is already enough even though the device is to be characterized under load tuning up to the third-order harmonic frequency, by utilizing X-parameters.

NVNA Techniques for Pulsed RF Measurements

In this article, we have reviewed various advanced broadband and pulsed measurement techniques which have been developed for sampler-based NVNAs. We have seen that the RF modulation capability of sampler based NVNAs was not limited by the IF bandwidth of its receiver. Two methods for pulsed-RF, pulsed-bias measurements were also presented. The method based on the concept of multiple recordings enables one to achieve pulsed-RF measurements with 0 dB desensitization (no dynamic range degradation) even for very low duty cycles. Real-time active load-pull techniques for the rapid design of microwave power amplifiers were also presented. Finally, it was demon strated that pulsed-RF real-time active-load-pull could also be performed for the rapid design of pulsed-RF PAs or the characterization of transistors with reduced memory effects. These various measurements with sampler-based NVNAs were made possible thanks to the use of advanced ADC triggering techniques.

A New Approach to Microwave Power Amplifier Design Based on the Experimental Characterization of the Intrinsic Electron-Device Load Line

This paper presents a new original approach to power amplifier design, which is mainly based on low-frequency nonlinear empirical electron device (ED) characterization. The proposed technique enables the same level of accuracy provided by expensive load-pull measurement systems to be obtained through a relatively simple and low-cost setup. Moreover, ED currents and voltages related to reliability issues can be directly monitored. Different experimental examples based on power GaAs and GaN field-effect transistors are provided to demonstrate the validity of the proposed approach.

Special issue on microwave power amplifier modeling, design, and system aspects

International Journal of RF and Microwave Computer-Aided EngineeringVolume 18, Issue 6 p. 505-506 Guest Editorial Special issue on microwave power amplifier modeling, design, and system aspects Franco Giannini, Franco Giannini Guest EditorSearch for more papers by this authorGottfried Magerl, Gottfried Magerl Guest EditorSearch for more papers by this author Franco Giannini, Franco Giannini Guest EditorSearch for more papers by this authorGottfried Magerl, Gottfried Magerl Guest EditorSearch for more papers by this author First published: 20 June 2008 https://doi.org/10.1002/mmce.20325AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue6Special Issue: Microwave Power Amplifier Modeling, Design, and System AspectsNovember 2008Pages 505-506 RelatedInformation

Sensitivity of electrical baseband memory effects to higher-order IF components for high-power LDMOS power amplifiers

Memory effects are complex phenomena that present major design problems in modern high-power microwave power amplifier (PA) design, having a large influence on the suitability of a PA to linearisation through pre-distortion. Presented are detailed modulated measurements that clearly show how baseband electrical memory, introduced by the baseband impedance presented to the device, is by far the most significant contributor to overall observed memory effects in a high-power LDMOS PA design. These investigations are performed on a 20W LDMOS device characterised at 2.1 GHz within a purpose-built, high-power measurement system.

RF and microwave power amplifier design by Andrei Grebennikov, McGraw-Hill, New York

RF and microwave power amplifier design by Andrei Grebennikov, McGraw-Hill, New York

RF and microwave power amplifier design by Andrei Grebennikov, McGraw-Hill, New York

RF and microwave power amplifier design by Andrei Grebennikov, McGraw-Hill, New York

Accurate simulation models yield high-efficiency power amplifier design

The design of RF and microwave power amplifiers continues to be somewhat of an art yet to be reduced to a systematic repeatable design practice on a wide-scale basis, despite the many excellent treatments of the subject in the literature and a number of courses. The general unavailability of sufficiently accurate and reliable nonlinear models for power transistors has been a major factor in limiting the accuracy of power amplifier (PA) simulation results. Suitable nonlinear models must properly treat the nonlinear and combined dc/ac analysis required for proper power compression and efficiency simulation under varied load and bias conditions. In this article, an accurate nonlinear transistor model is shown to form the basis for a systematic simulation-based design procedure for a microwave PA.

Guest editorial: Special Issue on Microwave Power Amplifier Modeling and Design

Guest editorial: Special Issue on Microwave Power Amplifier Modeling and Design

Nonlinear approaches to the design of microwave power amplifiers

Commonly used approaches for the design of power amplifiers (PAs), specifically in the microwave and millimeter-wave frequency range, are reviewed and discussed. Measurement-based techniques are compared with CAD-based approaches, stressing their relative strengths and weaknesses. Simplified techniques are also discussed, particularly addressing the preliminary evaluation of the power capabilities of a given device and to gather physical insight into the power-generating mechanisms. Finally, harmonic tuning for high-efficiency power amplifier design is outlined, together with its basic application rules. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE 14: 493–506, 2004.

Analysis and design of novel structures of artificial transmission lines for MMIC/MHMIC technology

In this paper, some new types of artificial transmission lines, compatible with monolithic-microwave integrated-circuit/miniature hybrid-microwave integrated-circuit technology are presented. In the new designs, short subsections of different lines are connected together to achieve the needed performance of various transmission-line functions such as impedance transformation, power coupling, etc. Theoretical calculations are given and some typical design data are provided, including models of extremely low impedance lines, which are very practical in the design of microwave power amplifiers and oscillators using heterojunction bipolar transistors or high electron-mobility transistors. Calculation results are validated by simulations and experiments. The proposed structures are very flexible and can easily provide transmission lines with widely varying characteristics.

Thermal design of gallium arsenide MESFETs for microwave power amplifiers

In the traditional design of microwave power amplifiers using gallium arsenide field effect transistors, the active devices are mounted onto a thermally conducting heatsink, and matching circuits at the input and output take the form of microstrip, usually using aluminium oxide as the dielectric. The thermal attachment of the transistor is often a problem with this technology and the use of many bond wires can lead to manufacturing problems because of unpredictable phase shifts associated with their variable length. The author describes a number of surface mount alternatives to this technology and assesses the associated thermal implications. Three dielectric alternatives are considered, namely aluminium oxide, aluminium nitride and diamond.

Nonlinear mixed analysis/optimization algorithm for microwave power amplifier design

A nonlinear mixed analysis/optimization algorithm for the design of microwave power amplifiers is presented. Matching conditions for optimum power and efficiency performance are imposed together with the balancing equations of the nonlinear analysis in a consistent way. The analysis/preoptimization of the power stage requires a computation time comparable to or smaller than a single conventional harmonic balance analysis. The algorithm forms the basis of a design procedure for the fulfilment of design specifications in terms of output power, power-added efficiency, and gain. Comparisons to the results of commercial CAD nonlinear analysis programs are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>