Broadband High Power Amplifier Research Articles

Design of a broadband GaN 12 W power amplifier

AbstractA compact broadband 12 W power amplifier with broadband matching networks is presented. Transistors connected in parallel are used to synthesize the high power. Input, interstage, and output matching networks are also properly designed to meet the requirement of the broadband application. The broadband high power amplifier (HPA) was fabricated using a 0.15‐μm gallium nitride (GaN) HEMT technology, with a maximum saturated measured output power of 43 dBm from 6 to 18 GHz. The measured power added efficiency exceeds 20% in the whole interested band. The proposed HPA also has a compact size of 3.1 mm × 2.96 mm.

Design of a Broadband MMIC Driver Amplifier with Enhanced Feedback and Temperature Compensation Technique

This paper presents a broadband GaN pseudo high-electron-mobility transistor (pHEMT) two-stage driver amplifier based on an enhanced feedback technique for a wideband system. Through well-designed parameter values of the feedback and the matching structure of the circuit, a relatively flat frequency response was obtained over a wide frequency band. Simultaneously, in order to reduce the fluctuation of current caused by the environmental temperature, a bias circuit with quiescent current temperature compensation was designed. The driver power amplifier, which was implemented in the form of a monolithic microwave integrated circuit (MMIC), was designed to drive a broadband high-power amplifier. The designed broadband driver amplifier for the 6 GHz to 20 GHz frequency band had a very small die size of 1.5 × 1.2 mm2 due to the use of an optimized impedance matching structure. It exhibited a small-signal gain of 12.5 dB and output power of 26 dBm. The flatness of this driver amplifier for gain and output power was achieved as ±2.5 dB and ±1 dB over the entire frequency band, respectively. The experimental results showed up to 35 dBm in the OIP3, and the current variation range was ±5 mA after using the temperature compensation bias circuit.

Design and fabrication methodology for industrial broadband high power amplifiers

This study presents a design and fabrication methodology for industrial broadband high power amplifiers (HPAs). The proposed method considers design constraints for broadband HPAs and parasitic effects arising from the fabrication process. This method is based on power combining networks (PCNs) whose characteristics such as power handling constraints, insertion loss, and bandwidth depend on the employed structure. Another important set of challenges is the technical faults and parasitics that occur during the fabrication process such as inequalities among different paths of PCNs, active and passive inherent mismatches, and many uncertainties in the fabrication and integration of a complicated large system. As such, the authors introduce a model for estimating the effects of path inequalities using a Gaussian function. For validation of the proposed methodology, a 2–6 GHz, 50 dBm output power broadband HPA system, which satisfies IEC-61000-4-3 RF radiant immunity measurement, was designed and fabricated. Furthermore, the measurement results exhibit the power-added efficiency of 10–28% and 48–51 dBm output power in the frequency bandwidth 2–6 GHz, which verify the capability of the proposed method for reliable estimation of the fabrication parasitics.

High‐power multi‐octave laterally diffused metal–oxide–semiconductor power amplifier with resistive harmonic termination

In this study, a broadband high-power amplifier with resistive harmonic matching is introduced. The analytical formulations for the drain voltage, output power, optimum load resistance, and efficiency are derived for this type of amplifier under class-B bias conditions. The design is based on a linear model of a laterally diffused metal–oxide–semiconductor transistor. In contrast to the conventional linear method that is based on an equivalent output circuit, the output matching circuit is designed in the presence of the dependent current source and intrinsic elements of the transistor. The design technique permits a broadband amplifier to be realised without load–pull measurement. The broadband power amplifier is intended for operation in the frequency range of 30–1000 MHz and covers the very high-frequency (HF) and ultra-HF bands. The power amplifier delivers 100 W to a 50 Ω load with efficiencies of 38–56%. To validate the design concept, the measured performance of the power amplifier is compared with simulations that incorporate a non-linear model of the transistor. The power amplifier is not driven into saturation and exhibits 2nd and 3rd harmonics of <−20 and <−10 dBc, respectively.

Broadband High-Power W-Band Amplifier MMICs Based on Stacked-HEMT Unit Cells

This paper reports on a broadband high-power amplifier (HPA) millimeter-wave integrated circuit (MMIC) covering the extended W-band (65–125 GHz). The MMIC is based on the Fraunhofer IAF 50-nm gate-length metamorphic high-electron-mobility transistor (mHEMT) technology. The HPA consists of two parallelized unit amplifiers. Each unit amplifier (UA) utilizes four stacked-HEMT unit power cells (UPCs) and four-way power combiners at the input and output. The UPCs stack four transistors with a gate width of $4\times 40~\mu \text{m}$ per HEMT. The UA achieves an average small-signal gain of 19.4 dB and an average saturated output power of 21.6 dBm at least from 70 to 110 GHz. The HPA yields an average small-signal gain of 16.8 dB and an average saturated output power of 22.5 dBm at least from 68 to 110 GHz. A peak output power of 24.1 dBm is achieved at an operating frequency of 75 GHz.

400 W broadband power amplifier using transmission-line transformers with 1:8 impedance transformation ratio

This paper presents a broadband high-power amplifier using transmission-line transformers with a high impedance transformation ratio. Two series-connected transformers with 1:8 and 1:1 impedance transformation ratios are used at the load network of a single-balanced high-power amplifier to match the low load impedance in broadband. The same transformer configuration is also used at the input network. A negative feedback is applied to improve the gain flatness and to increase the stability over the broadband. In order to validate the proposed circuit structure, a broadband high-power amplifier is designed and implemented to achieve an output power of more than 400 W in the frequency band of 30 to 500 MHz. The implemented power amplifier exhibits a flat gain response within 1.80 dB at an average of 19.1 dB and high power-added efficiencies of 28.0 to 56.9 at an output power of 400 W over the entire frequency band.

High-Power 20-100-MHz Linear and Efficient Power-Amplifier Design

This paper presents modeling and analysis of the realization of high-power broadband RF power amplifiers (PAs) and power combiners. In the scope of the study, a model is proposed for a transmission line with a ferrite core, which is the basic building block for the transmission line transformers (TLTs) used in broadband high-power amplifiers and power combiner/divider networks as a building block. Simulated performances of the designed networks using the proposed model possess high conformity with the empirical performance of the corresponding realized networks. Therefore, broadband TLT networks with low insertion loss, high power-handling capability, and low return loss are realized. RF power combiner/divider networks with wide frequency bandwidth and high isolation are also implemented. By using class-B biased pushpull network topology, a linear and wideband RF PA is realized with high drain efficiency at high output power levels. In order to broaden the operating frequency range of the indicated amplifier, a novel technique for TLT utilization that matches the output impedance of the RF power transistor in wideband is proposed and realized. Measurement results satisfy the design specifications.

0.7–2.7-GHz 12-W Power-Amplifier MMIC Developed Using MLP Technology

A design approach and test data for a broadband high-power amplifier monolithic microwave integrated circuit (MMIC) developed using MSAG MESFETs with multilevel-plating technology are presented. A low-loss matching design technique was used in the development of a two-stage amplifier. The UHF/L/S-band amplifier has exhibited greater than 12-W power output and better than 22% power-added efficiency over the 0.7-2.7-GHz frequency range. To our knowledge, these power results represent the state-of-the-art in multioctave high-power MMIC amplifiers