Gallium Nitride Power Amplifier Research Articles

3.3-4.3 GHz efficient continuous class-F gallium nitride power amplifier based on simplified real frequency technique and harmonic tuning.

In order to implement the fifth generation (5G) communication system for a large number of users, the governments of many countries nominated the low 5G frequency band between 3.3 and 4.3 GHz. This paper proposes a wideband RFPA by designing the input matching network (MN) and output MN of the device using the simplified real frequency technique (SRFT) and the harmonic tuning network. The load-pull and source-pull is applied at multiple points for 100 MHz intervals over the bandwidth to obtain the optimum impedances at the output and input of the 10W Gallium Nitride (GaN) Cree CGH40010F device. To verify the design, the RFPA is simulated, and the performance is measured between 3.3 and 4.3 GHz. According to experimental findings, the measured drain efficiency (DE) throughout the whole bandwidth ranged from 57.5 to 67.5% at the output power of 40 dBm. Moreover, at the 1 dB compression point between 39.2 and 42.2 dBm output power, the drain efficiency (DE) achieves a high value of 81.2% with an output power of 42.2 dBm at a frequency of 3.3 GHz. The RFPA can obtain a maximum gain of 12.4 dB at 3.5 GHz. The linearity of the RFPA with a two-tone signal is measured and the value is less than -22 dBc all over the band.

Millimeter-Wave GaN High-Power Amplifier MMIC Design Guideline Considering a Source via Effect

A millimeter-wave (mmWave) gallium nitride (GaN) high-power amplifier (HPA) monolithic microwave-integrated circuit (MMIC) was implemented, considering a source via effect. In this paper, we introduce guidelines for designing GaN HPA MMICs, from device sizing to meeting high-power specifications, power matching considering source via effects, schematic design of three-stage amplifier structures, and electromagnetic (EM) simulation. Based on the results of load pull simulation and small-signal maximum stable gain (MSG) simulation, the GaN high-electron-mobility transistor (HEMT) size was selected to be 8 × 70 μm. However, since the source via model provided by the foundry was significantly different from the EM results, it was necessary to readjust the power matching considering this. Additionally, when selecting the source via size, the larger the size, the easier the matching, but since the layout of the peripheral bias circuit is not possible, a compromise was required considering the actual layout. To prevent in-band oscillation, an RC parallel circuit was added to the input matching circuit, and low-frequency oscillation was solved by adding a gate resistor on the PCB module. The proposed PA was fabricated with a commercial 0.1 μm GaN HEMT MMIC process. It exhibited 38.56 to 39.71 dBm output power (Pout), 14.2 to 16.7 dB linear gain, and 14.1% to 18.2% power-added efficiency (PAE) in the upper Ka band. The fabricated GaN power amplifier MMIC shows competitive Pout in the upper Ka band above 33 GHz.

Design and Development of GaN-Based Power Amplifier for Radar Applications

This paper presents a comprehensive overview of Gallium nitride (GaN)-based power amplifier (PA) design for various frequency bands. GaN-based technology has emerged as a promising alternative to traditional silicon-based amplifiers due to its superior performance characteristics, which are discussed in this paper. This paper also discusses the key design parameters and challenges associated with PA design. Various design techniques and topologies for GaN power amplifiers are explored besides addressing theoretical considerations of PA design along with a complete systematic design procedure for L-Band amplifier using the wolfspeed large signal GaN HEMT model. To further demonstrate the useful methodology, the designs of S-band and C-band PAs are also presented. GaN-based devices are very promising candidates for high-power applications. It is widely used in various high-power applications including communication and radar.

An E band MMIC power amplifier design using 100 nm T‐Gate GaN HEMT on SiC

SummaryThe small signal modeling, design, fabrication, and measurement about monolithic millimeter‐wave integrated circuit (MMIC) using gallium nitride (GaN) power amplifier (PA) on silicon carbide (SiC) working at the E band are proposed in this paper. The two stage PA used customized 4 × 75 μm transistor with 100 nm T gate technology. The extraction and optimization of small signal model are based on single GaN high electron mobility transistor (HEMT)'s measurement. Balanced structure and new method are used by low impedance matching, which can simplify circuits prominently and benefit for die size reduction. Radial stub and LC stub are made the whole circuit in absolute stable status; the in‐series DC block metal–insulator–metal capacitor from the matching circuit ensure the process is within small tolerances. From the 61–66 GHz bandwidth, a peak 10.7 dB small signal gain is obtained from the designed MMIC GaN PA, and also, the maximum output power can reach 29.7 to 30.4 dBm from 61 to 66 GHz, with an associated the peak drain efficiency of 18.8%. The final die size without dicing slot is 3.0 × 1.74 mm2.

Gallium Nitride Power Amplifiers for Ka-Band Satcom Applications: Requirements, Trends, and the Way Forward

Gallium Nitride Power Amplifiers for Ka-Band Satcom Applications: Requirements, Trends, and the Way Forward

Analysis of the impact of prototyping‐related parasitic effects in a hybrid GaN power amplifier for 5G FR1 applications

AbstractThis article analyses the impact of parasitic effects encountered in the manufacturing of a Gallium Nitride power amplifier optimized for a specific trade‐off of efficiency and linearity at 5G FR1 frequencies. The analysis focuses on an example based on a packaged transistor and implemented in hybrid technology, adopting a two‐layer printed circuit board for passive distributed elements and surface‐mount lumped components. The design is summarized, and the focus is then posed on the comparison of simulated and measured results, the main causes of inaccuracy in their agreement, and a simple way of reproducing these in simulation. The mechanical stability of the assembly and the sensitivity of the second harmonic control are identified as the main sources of performance degradation. These effects are correctly modeled at the simulation level thanks to the insertion of specific parasitic lumped elements but could not be fully eliminated at the experimental level in this specific prototype. However, post‐tuning performed on the prototype, guided by the proposed analysis, still allows to reach satisfactory performance although somewhat sub‐optimal compared to the one expected from simulations. At 3.5 GHz, the re‐tuned PA demonstrates a measured output power in excess of 37.5 dBm at saturation, with associated gain higher than 14 dB and PAE of 60%. In a 2‐tone test with 20 MHz spacing, the IMD3 remains lower than −30 dBc up to 29 dBm of output power with a corresponding PAE of the order of 32%.

Nonlinear Capacitance Compensation Technique in a Linearity-Enhanced and Broadband GaN PA MMIC for Ku-/K-Band Applications

This article reports on exploiting a nonlinear capacitance compensation technique to achieve high linearity for power amplifier (PA) designs in III–V semiconductor technologies. High linearity is achieved by implementing multiple transistors with deliberate sizes and biasing to compensate for each nonlinear input capacitance behavior. Therefore, the composed PA core acts as one large device where each subdevice is biased individually. Moreover, this approach proves to be a reliable and easy way to improve PA linearity in III–V semiconductor technologies. The viability of this compensation is demonstrated by comparing it to other analog linearity improvement techniques such as derivative superposition. As a proof-of-concept prototype, a 17.2–20.2-GHz class-AB PA is designed in a space-evaluated 150-nm gallium nitride (GaN)-on-silicon carbide (SiC) process. Its capabilities are validated for various modulation bandwidths up to 500 MHz at several frequencies while delivering 32 dBm of output power. The measured third-order intermodulation distortion (IMD <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_3$</tex-math> </inline-formula> ) and the fifth-order intermodulation distortion (IMD <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_5$</tex-math> </inline-formula> ) are improved by 18 and 25 dB, respectively, compared to a class-AB design. The measured amplitude-to-phase (AM–PM) distortion of less than 0.07 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^\circ$</tex-math> </inline-formula> is obtained over the entire bandwidth. Finally, noise-to-power ratio (NPR) results prove the linearity enhancement concept with values better than 15 dB up to maximum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\rm out}$</tex-math> </inline-formula> . All the results were measured without any applied digital predistortion (DPD).

Effective Digital Predistortion (DPD) on a Broadband Millimeter-Wave GaN Power Amplifier Using LTE 64-QAM Waveforms

We demonstrate in this work effective linearization on a millimeter-wave (mm-Wave) broadband monolithic gallium nitride (GaN) power amplifier (PA) using digital predistortion (DPD). The PA used is a two-stage common-source (CS)/2-stack PA that operates in the mm-Wave 5G FR2 band, and it is linearized with the generalized memory polynomial (GMP) DPD and tested using 4G (4th generation) long-term-evolution (LTE) 64-QAM (quadrature amplitude modulation) modulated signals with a PAPR (peak-to-average power ratio) of 8 dB. Measurement results after implementing GMP DPD indicate considerable broadband improvement in the adjacent channel leakage power ratio (ACLR) of 16.9 dB/17.3 dB/16.5 dB/15.1 dB at 24 GHz/28 GHz/37 GHz/39 GHz, respectively, with a common average POUT of 15 dBm using a 100 MHz LTE 64-QAM input signal. At a fixed frequency of 28 GHz, the GaN PA after GMP DPD achieved signal bandwidth-dependent ACLR improvement and root-mean-square (rms) EVM (error vector magnitude) reduction using 20 MHz/40 MHz/80 MHz/100 MHz LTE 64-QAM waveforms with a common average POUT of 15 dBm. The GaN PA thus achieved very good linearization results compared to that in other state-of-the-art mm-Wave PA DPD studies in the literature, suggesting that GMP DPD should be rather effective for linearizing mm-Wave 5G broadband GaN PAs to improve POUT, Linear.

Electrothermal Responses of Bonding Wire Arrays in GaN Power Amplifier

The device reliability problems of the bonding wire array in gallium nitride (GaN)-based high electron mobility transistor (HEMT) power amplifier become more and more serious due to high-voltage operation, impedance mismatching conditions, and so on. In this paper, both the experimental and theoretical studies on the electrothermal responses of bonding wire arrays in GaN power amplifier are performed. By using the finite element method to self-consistently solve the current transport and heat conduction equations, the temperature distributions of the GaN die surface and the bonding wire array under the continuous wave input signals of different power can be obtained, which are consistent with the experimental results captured by the IR microscopy of the measurement system.

Adversarial attacks and active defense on deep learning based identification of GaN power amplifiers under physical perturbation

Deep learning (DL)-based radiofrequency (RF) fingerprinting identification has shown significantly growing importance in the wireless industry including 5G, IoT and Wireless Sensor Networks (WSN). However, there is little investigation on the robustness of the corresponding DL models against adversarial attacks and adversarial defense. This paper discusses the effects of four cutting-edge adversarial attacks on DL-based RF fingerprinting identification and provides a graphical analysis of RF feature perturbations following adversarial attacks. For the first time we also demonstrate the results of combined physical attack (i.e. tuning the drain currents of the power amplifiers) by tuning the physical features of the device hardware (i.e. drain current), and adversarial attacks on DL-based classifiers. Experimental results from 16 Gallium nitride (GaN) power amplifiers (PA) reveal that adversarial attacks can seriously deteriorate the accuracy of RF identification from about 100.00% to below 10.00% even with only 0.50% adversarial perturbation. In order to deal with the problem of decreased accuracy caused by attacks, we proposed an adversarial defense method based on feature-level interpretability (FIAT), which improved the accuracy of RF identification with interpretability analysis. The results compared with several common defense methods validate that the proposed FIAT can maintain an accuracy of 96.00% even when the adversarial attack perturbation is 5.00% and with physical attack. Moreover, the changes of data features in the process of adversarial attacks and defense are given, providing a new way for the interpretability of adversarial attacks and defense on RF identification tasks.

A Millimeter-Wave GaN MMIC Front End Module with 5G NR Performance Verification

This paper proposes a millimeter-wave (mmWave) 5G front end module (FEM) based on multiple gallium nitride (GaN) monolithic microwave integrated circuits (MMICs) with 5G new radio (NR) performance verification. The proposed structure is configured by a wide band GaN single-pole double-throw (SPDT) switch MMIC, a GaN low-noise amplifier (LNA) MMIC, and a GaN power amplifier (PA) MMIC with the target operation band from 26.5 GHz to 29.5 GHz. The LNA and PA MMICs are designed with 150 nm GaN/SiC technology, and the SPDT MMIC is designed with 100 nm GaN/Si. The LNA MMIC shows the measured noise figure less than or equal to 2.52 dB within the operation band. The PA MMIC is based on a two-stage configuration and shows about 35 dBm measured saturated power with power-added efficiency better than 34% within the operation band. Also, the SPDT MMIC is based on an artificial transmission line configuration for wideband performance and shows that the measured insertion loss is less than 1.6 dB, and the measured isolation is higher than 25 dB within the operation band. Furthermore, all MMICs are integrated within a single carrier as an FEM and successfully verified by 5G NR test signals.

Coupled Embedding Networks for 7-dB Gain-per-Stage at 130–140 GHz in a 20-dBm Gallium Nitride Power Amplifier

We propose a coupled embedding network (CEN) as a portable, robust design technique to simultaneously introduce gain boosting and loadline matching in millimeter-wave power (mm-wave) amplifiers (PAs). The approach uses directional couplers as an abstraction for the embedding network and produces straightforward design equations to achieve optimal input-stability margins for any specified gain. We demonstrate the design process and implementation using a 40-nm Gallium Nitride (GaN) process technology through simulated and measured performance of the PA with and without the embedding network. The output power is greater than 20 dBm and remains above 18 dBm over an 8 GHz bandwidth. Peak power added efficiency (PAE) is 6.5%. The 3-stage PA achieves 21 dB of gain at 137 GHz offering 7.1-dB gain per device. The measured gain is 8 dB higher than the common-emitter design with the same number of stages. To our knowledge, this is the highest gain per stage for a GaN PA in D-band.

A 17–26.5 GHz 42.5 dBm broadband and highly efficient gallium nitride power amplifier design

A 17–26.5 GHz 42.5 dBm broadband and highly efficient gallium nitride power amplifier design

A UHF-band 100 W broadband hybrid GaN power amplifier based on the regional modulation of impedance distribution method

In this paper, the regional modulation of impedance distribution (RMID) method for broadband power amplifier design is presented. We design and fabricate a wideband UHF-band gallium nitride (GaN) power amplifier (PA) consists of 2-chips containing self-developed GaN high electron mobility transistors (HEMTs) on a SiC substrate with gate lengths and widths of 0.25 μm and 10 mm, respectively. The pre-matching network designed by the RMID method converts the port impedances of the device to smaller real impedances, and exchanges the lower impedance ratio for wider frequency band characteristics. The distribution curve of the impedance points is tensioned or compressed according to the characteristics of the impedance transformation paths of different matching elements. As a result, the impedance distribution curve within the broadband range shows “knotting” characteristics. Then, the smaller impedances are matched to 50 Ω by low-Q microstrip impedance transforming lines. The measured output power, gain and efficiency values of the amplifier are higher than 100 W, 16 dB and 60%, respectively across 0.3–1.0 GHz, and the fractional bandwidth is up to 108%.

Ku-Band 70-/30-W-Class Internally Matched GaN Power Amplifiers With Low IMD3 Over a Wide Offset Frequency Range of Up To 400 MHz

This study describes the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ku</i> -band 70- and 30-W-class internally matched gallium nitride (GaN) power amplifiers (PAs) for multi-carrier satellite communications (SatComs). The GaN PAs maintain low third-order intermodulation distortion (IMD3) over a wide offset frequency range of up to 400 MHz, whereas in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ku</i> -band, one PA can deliver a high peak output power of approximately 70 W and the other PA, a peak output power of higher than 30 W. To realize a wide offset frequency operation, our proposed output-matching circuit includes three different types of difference-frequency short circuits, two of which are embedded into a tournament-shaped output-matching circuit inside the PA package and the rest is embedded into the drain bias feed placed outside the package. To verify the short-circuit design and its effectiveness, two different power classes (70 and 30 W), <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ku</i> -band GaN PAs, were designed and fabricated, and then, their output transfer characteristics focusing on IMD3 were measured. The measurements show that the 70-W-class GaN PA achieves a peak output power of 48.6 dBm while maintaining a linear output power of over 40 dBm and an IMD3 of less than −26 dBc over wide offset frequencies ranging from 1 to 400 MHz. The 30-W-class GaN PA maintains a linear output power of over 36.3 dBm and an IMD3 of less than −27 dBc over wide offset frequencies of up to approximately 600 MHz. To the best of the authors’ knowledge, these PAs have a record output power level over a wide frequency range of 1–400 MHz or higher under the condition of a low IMD3 of less than −25 dBc, compared to previously reported <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ku</i> -band GaN PAs used for multi-carrier SatComs.

A compact broadband high power quasi-MMIC GaN power amplifier

PurposeThe design and implementation of a broadband quasi-monolithic microwave integrated circuit (q-MMIC) power amplifier (PA) is presented for 0.2 to 2.2 GHz applications.Design/methodology/approachTo obtain an efficient, high-gain and high-power performance with in a compact and low-cost size, the prototype is based on Gallium nitride (GaN) on SiC 0.25-µm transistors, whereas the passive matching networks are realized on an AlN substrate as thin film circuit.FindingsMeasured results of the q-MMIC PA across the 0.2 to 2.2 GHz band show at least 32 ± 3 dB small-signal gains, an output power of 7 to 12 W and an average power add efficiency greater than 54%. The q-MMIC occupies an area of 12.8 × 14.5 mm2.Originality/valueTo the best of the authors’ knowledge, this work reports the first full integrated PA which covers the frequency range of 0.2 to 2.2 GHz and achieves the combination of highest gain, about 10 W output power, together with the smallest component size among all published GaN PAs to date.

Mechanism of wireless power transfer system waveform distortion caused by nonideal gallium nitride transistor characteristics

Gallium nitride (GaN) field-effect transistors have low ON resistance and switching losses in high-frequency (>MHz) resonant wireless power transfer systems. Nevertheless, their performance in the system is determined by their characteristics and operation mode. A particular operating mode in a 6.78-MHz magnetic resonant wireless transfer system that employs class-D GaN power amplifiers in the zero-voltage switching mode is studied. Two operation modes, the forward mode and the reverse mode, are investigated. The nonideal effect under the device-level dynamic resistance and thermal effect are also analyzed. The dynamic resistance under different operation modes is demonstrated to have different generation mechanisms. Finally, the device characteristics with system operating conditions are combined, and the effects of temperature and dynamic resistance under different operating conditions are evaluated.

Frequency-Locked RF Power Oscillator With 43-dBm Output Power and 58% Efficiency

This article presents the frequency-locked high-power RF oscillator using a gallium nitride (GaN) high electron mobility transistor (HEMT) amplifier and phase-locked loop (PLL) for 2.4-GHz industrial, scientific, and medical (ISM) band applications. The proposed architecture exploits the GaN power amplifier in the positive-feedback loop, whereas the desired phase shift for the target oscillating frequency is regulated from the PLL. To the best of our knowledge, this work is the first to employ the frequency locking scheme for a high-power solid-state RF oscillator. A detailed analysis of the oscillation conditions and the efficiency is provided. The prototype circuit is implemented with hybrid phase shifters and a fractional- N frequency synthesizer. The implemented RF oscillator circuit operates from 2.3 to 2.575 GHz and achieves a low phase noise of -131.8 dBc/Hz at a 1-MHz offset frequency. The power efficiency of the proposed oscillator reaches 58%, and the PLL incurs only 0.2% efficiency degradation.

GaN Power Amplifier Digital Predistortion by Multi-Objective Optimization for Maximum RF Output Power

While digital predistortion (DPD) usually targets only the linearity performance of the radio–frequency (RF) power amplifier (PA), this work addresses more than a single PA performance metric exploiting a multi-objective optimization approach. We present a predistorer learning procedure based on a constrained optimization algorithm that maximizes the RF output power, while guaranteeing a prescribed linearity level, i.e., a maximum normalized mean square error (NMSE) or adjacent-channel power ratio (ACPR). Experimental results on a Gallium Nitride (GaN) PA show that the proposed approach outperforms the classical indirect learning architecture (ILA), yet using the same predistorter structure with predetermined nonlinearity and memory orders.

An 18–56-GHz Wideband GaN Low-Noise Amplifier With 2.2–4.4-dB Noise Figure

An 18-56-GHz gallium nitride (GaN) low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) is presented in this letter. This LNA is fabricated with commercial 0.1-μm gate-length GaN-on-silicon (GaN/Si) process. The gain is 16-21.5 dB and the |S11| and |S22| are below -5 dB across the band. The noise figure (NF) is 2.2-4.4 dB and the output power at 1-dB compression point (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dB</sub> ) is 10-20 dBm. This LNA has four-stage-cascade and common-source structure with 4.8 × 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> chip area. The dc power dissipation is 1.4 W. To the best of the author's knowledge, there has been no GaN LNA covering such a wide bandwidth at this frequency range. This LNA shows ultrawide bandwidth, low NF, high linearity, and high robustness. Moreover, it can be directly integrated with GaN power amplifiers (PAs) and switches to realize the monolithic RF front-ends, which can largely reduce the packaging loss and the module volume. This LNA has a great potential in wideband, high-speed, high-reliability, and high-integration applications.