K-Band High-Power GaAs FET Amplifiers

Lumped-element internal matching techniques were successfully adopted for K-band power GaAs FET amplifiers. The developed 18-GHz band two-stage amplifier provides 1.05-W power output at 1-dB gain compression and 1.26-W saturated power output with 8.1-dB small-signal gain. The 20-GHz band single-stage amplifier has 1.04-W power output with 3-dB associated gain. Lumped-element internal matching circuit design as well as amplifier fabrication are described. Intermodulation distortion and AM-to-PM conversion characteristics are also presented.     

10-GHz 10-W Internally Matched Flip-Chip GaAs Power FET's

A newly developed internally matched configuration for a flip-chip GaAs power field effect transistor is presented. In this structure, gate and drain electrodes of the FET chips are directly connected to the lumped dielectric capacitors in the matching networks by thermocompression bonding using no wire. A power output of 10 W with 3-dB gain and a power added efficiency as high as 14 percent has been realized at 10 GHz.     

GaAs microwave power FET

A design consideration for an X-band GaAs power FET, features of the fabrication process, and electrical characteristics of the FET are described. Interdigitated 53 source and 52 drain electrodes and an overlaid gate electrode for connecting 104 Schottky gates in parallel have been introduced to achieve a 1.5-µm-long and 5200-µm-wide gate FET. A sheet grounding technique has been developed in order to minimize the common source lead inductance (L8= 50 pH). The resulting devices can produce 0.7-W and 1.6-W saturation output power at 10 GHz and 8 GHz, respectively. At 6 GHz, a linear gain of 7 dB, an output power of 0.85 W at 1-dB gain compression and 30-percent power added efficiency can be achieved. The intercept point for third-order intermodulation products is 37.5 dBm at 6.2 GHz.     

A 25-W 5-GHz GaAs FET Amplifier for a Microwave Landing System

A 25-W 29-dB gain 5-GHz GaAs FET amplifier has been developed which can be used for a transmitter in the Microwave Landing System. By using 10-W class practical internally matched GaAs FET's hermetically sealed in ceramic packages, the four-stage amplifier has been constructed simply. The amplifier provides 30-W power output with 18.5 percent power efficiency at 17-dBm power input level. It also exhibited an exceffent AM/PM conversion of approximately 1°/dB, compared to 6°/dB for TWT amplifiers.     

A Single Supply, High Linearity 2-W PA MMIC for WLAN Applications Using Quasi-Enhancement Mode PHEMTs

A fully matched, 2-W high linearity amplifier monolithic microwave integrated circuit, by using quasi-enhancement mode technology of AlGaAs/InGaAs/ GaAs pseudomorphic high electron mobility transistors, is demonstrated for wireless local area network applications. At Vgs= 0 V, V_ds= 5 V, this power amplifier has achieved 14-dB small-signal gain, 33-dBm output power at 1-dB gain compression point, and 34.5-dBm saturated output power with 35% power added efficiency at 5.8 GHz. Moreover, high-linearity with 45.2-dBm third-order intercept point is also achieved     

Development of GaAs monolithic power amplifiers in X-band

The design, fabrication, and performance of several GaAs FET monolithic circuits are described. These include a two-stage, four-FET push-pull amplifier that has exhibited 1.4-W output power with 12.4-dB gain at 9.0 GHz, and a three-transistor monolithic paraphase amplifier (unbalanced input, balanced output) exhibiting 6-dB small-signal gain and a 1-dB gain compression point of 20 dBm. The amplifier chips utilize monolithically fabricated inductors, capacitors, and transmission lines to accomplish on-the-chip impedance matching.     

A 20 GHz Band 0.5 W GaAs FET Amplifier for Satellite Communications

GaAs FET amplifier modules for 20 GHz band satellite communications have been developed using newly developed power FETs. The deep recess gate structure was adopted in the power FET, which improved both power output capability and power gain. Power added efficiency of 22 percent with more than 1 W power output has been achieved with 3 mm gate width FETs. The amplifier modules containing two-stage internally matched FET's can be hermetically sealed in metal packages. The modules had 8.4-8.9 dB linear gain in the 17.7-18.8 GHz band and 7.9-8.4 dB linear gain in the 18.5-19.6 GHz band. The power output at 1 dB gain compression point was more than 0.5 W. The third-order intermodulation distortion ratio was 81-83 dB at 18.2 GHz and 77-80 dB at 18.9 GHz, when individual output signal power was -4 dBm.     

11.GHz GaAs Power MESFET Load-Pull Measurements Utilizing a New Method of Determining Tuner Y Parameters

A Ioad-pull technique utilizing a new method of determining tuner Y parameters is proposed for huge-signal characterization of microwave power transistors. Large-signal input-output transfer characteristics of an active circuit containing a GaAs FET and an input matching circuit are measured by inserting a microstrip tuner between the active circuit output drain terminal and the 50-Omega load. The microstrip-tuner Y parameters are determined by comparing the dc bias-dependent small-signal S parameter S/sub 22/ of the active circuit and that of the circuit which contains the active circuit and microstrip tuner. The reflection coefficient presented to the active circuit output drain terminal is derived from tuner Y parameters. Optimal load impedances for output power, obtained with this new Ioad-pull technique, are used to design X-band GaAs FET power amplifiers. An 11-GHz power amplifier with a 3000-mu m gate-width FET chip delivers 1-W microwave power output with 4-dB gain in the 500-MHz band.     

8GHz带有RC稳定网络的AIGaN/GaN HEMTs内匹配功率合成放大器的设计

设计了工作在8GHz的基于AIGaN/GaN HEMTs的内匹配功率合成放大器.输入和输出匹配电路制作在0.381mm厚的氧化铝陶瓷基片上,为了提高整个电路的稳定因子K,在电路输入端增加了片上RC有损网络.在8GHz测出连续波ldB压缩点时的输出功率为PldB=43dBm(20W),线性增益7.3dB,最大PAE为38.1%,合成效率达到70.6%.     

8GHz带有RC稳定网络的AlGaN/GaN HEMTs内匹配功率合成放大器的设计

设计了工作在8GHz的基于AIGaN/GaN HEMTs的内匹配功率合成放大器.输入和输出匹配电路制作在0.381mm厚的氧化铝陶瓷基片上,为了提高整个电路的稳定因子K,在电路输入端增加了片上RC有损网络.在8GHz测出连续波ldB压缩点时的输出功率为PldB=43dBm(20W),线性增益7.3dB,最大PAE为38.1%,合成效率达到70.6%.     

GaAs Dual-Gate FET for Operation Up to K-Band

A high-frequency equivalent circuit model of a GaAs dual-gate FET and analytical expressions for the input/output impedances, transconductance, unilateral gain, and stability factor are presented in this paper. It is found that the gain of a dual-gate FET is higher than that of a single-gate FET at low frequency, but it decreases faster as frequency increases because of the capacitive shunting effect of the second gate. A dual-gate power FET suitable for variable gain amplifier applications up to K-band has been developed. At 10 GHz, a I.2-mm gatewidth device has achieved an output power of 1.1 W with 10.5-dB gain and 31-percent power-added efficiency. At 20 GHz, the same device delivered an output power of 340 mW with 5.3-dB gain. At K-band, a dynamic gain control range of up to 45 dB was obtained with an insertion phase change of no more than +-2 degrees for the first 10 dB of gain control.     

A monolithic GaAs DC to 2-GHz feedback amplifier

Resistive feedback in low-frequency FET amplifiers is an attractive method of simultaneously attaining gain flatness and excellent input-output VSWR over wide bandwidths. Combined with simple matching circuitry, the feedback approach allows the design of general-purpose utility amplifiers requiring much less chip area than when conventional matching techniques are used. The 1.5- by 1.5-mm chip described in this paper provides 10-dB ± 1-dB gain, excellent input and output VSWR, and saturated output power in excess of + 20 dBm, from below 5 MHz to 2 GHz. The noise figure is approximately 2 dB when biased for minimum noise, with an associated gain of 9 dB.     

A Monolithic GaAs DC to 2-GHz Feedback Amplifier

Resistive feedback in low-frequency FET amplifiers is an attractive method of simultaneously attaining gain flatness and excellent input-output VSWR over wide bandwidths. Combined with simple matching circnitry, the feedback approach allows the design of general-purpose utility amplifiers requiring much less chip area than when conventional matching techniques are used, The 1.5- by 1.5-mm chip desenbed in this paper provides 10-dB +-1-dB gain, excellent input and output VSWR, and saturated output power in excess of +20 dBm, from below 5 MHz to 2 GHz. The noise figure is approximately 2 dB when biased for minimum noise, with an associated gain of 9 dB.     

A single-supply Ku-band 1-W power amplifier MMIC with compact self-bias PHEMTs

In this letter, the design of a self-bias 1.8-mm AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor with a compact source capacitor for operation in Ku-band frequency is described. Based on the proposed device, a self-bias Ku-band 1-W two-stage power amplifier monolithic microwave integrated circuit (MMIC) is also demonstrated. Under a single bias condition of 8 V and 630 mA, the self-bias MMIC possesses 14.2-dB small-signal gain, 30.2-dBm output power at 1-dB gain compression point with 19.2% power added efficiency and 31.3-dBm saturated output power with 22.5% power added efficiency at 14GHz. With the performance comparable to the dual-bias MMIC counterpart, the proposed self-bias MMIC is more attractive to system designers on very small aperture terminal applications.     

Improved power performance for a recessed-gate AlGaN-GaN heterojunction FET with a field-modulating plate

A recessed-gate AlGaN-GaN field-modulating plate (FP) field-effect transistor (FET) was successfully fabricated on an SiC substrate. By employing a recessed-gate structure on an FP FET, the transconductance was increased from 150 to 270 mS/mm, leading to an improvement in gain characteristics, and current collapse was minimized. At 2 GHz, a 48-mm-wide recessed FP FET exhibited a record output power of 230 W (4.8 W/mm) with 67% power-added efficiency and 9.5-dB linear gain with a drain bias of 53 V.     

11 GHz and 12 GHz multiwatt internal matching for power GaAs f.e.t.s

Multiwatt internal-matching techniques for multichip power GaAs f.e.t.s at 11 GHz and 12 GHz bands have been developed, adopting a lumped-element input circuit and a semidistributed output circuit. The internally matched device for the 11 GHz band exhibits 4 W power output with 3.4 dB associated gain, and the 12 GHz device 3.6 W power output with 3 dB associated gain.     

X-band power AlGaAsInGaAs P-n-p HBTs

AlGaAs/InGaAs P-n-p heterojunction bipolar transistors (HBTs) were fabricated using carbon-doped material grown by nonarsine metal-organic vapor-phase epitaxy (MOVPE). F_max of 39 GHz and f_t of 18 GHz were obtained. Operated in common-base mode, a P-n-p HBT achieved 0.5-W output power with 8-dB gain at 10 GHz; saturated output power was 0.69 W. Results are presented for devices with emitter lengths from 120 to 600 μm     

A Compact 6.5-W PHEMT MMIC Power Amplifier for Ku-Band Applications

A compact 6.5-W AlGaAs/InGaAs/GaAs PHEMT monolithic microwave integrated circuit (MMIC) power amplifier (PA) for Ku-band applications is proposed. This two-stage amplifier with chip size of 8.554mm² (3.64mmtimes2.35mm) is designed to fully match 50-Omega input and output impedance. Under 8V and 2000mA dc bias condition, the PA deliver 38.1dBm (6.5W) saturated output power, 10.5-dB small signal gain and peak power added efficiency of 24.6% from 13.6 to 14.2GHz. This MMIC also achieved the best power densities (760mW/mm²) at Ku band reported to date     

A Packaged 20-GHz 1-W GaAs MESFET with a Novel Via-Hole Plated Heat Sink Structure

A novel Via-Hole plated heat sink (PHS) structure with an improved gate-packing density is developed for K-band GaAs power FET's. The gate-packing density in this structure is increased to four times greater than that in the conventional direct via-hole structure, by making via-holes under the source-grounding pads fabricated outside the FET active area. The increase in the gate-packing density allows the design of a high-power, high-frequency FET with a larger gate periphery. The resultant 2.4-mm gate periphery device with 0.7µm gate length delivered 1.1 W (30.4 dBm) of output power with 5.0-dB gain and 19.2-percent power added efficiency at 20 GHz, and exhibited 0.74 W (28.7 dBm) at 30 GHz. The same type of device assembled in the hermetically sealed package delivered 1.0 W (30 dBm) of output power with 4.8-dB gain and 13-percent power added efficiency at 20 GHz. Thermal and mechanical-environmental tests were made to assess the reliability of the novel Via-Hole PHS FET. Results showed no failure nor significant change in device parameters throughout the tests.     

A K-Band GaAs FET Amplifier with 8.2-W Output Power

An 8.2-W GaAs FET amplifier with 38.6+-0.5-dB gain over a 17.7-19.1 GHz frequency band has been developed. This amplifier combines the outputs of eight multistage amplifier modules utilizing a radial combiner. This state-of-the-art power level has been achieved with AM/PM of less than 2°/dB. The third-order intermodulation products at 1-dB gain compression were 20 dBc, and variation in group delay over the frequency band was less than +-0.25 ns. Tests show that the amplifier is unconditionally stable and follows the graceful degradation principle.