Chih Cheng Wang

A fully matched high linearity 2-W PHEMT MMIC power amplifier for 3.5 GHz applications

A 2-W monolithic microwave integrated circuit power amplifier, operating between 3.3 and 3.8GHz by implementing AlGaAs/InGaAs/GaAs pseudomorphic high electronic mobility transistor for the applications of wideband code division multiple access, wireless local loop, and multichannel multipoint distribution service, is demonstrated. This two-stage amplifier is designed to fully match 50/spl Omega/ input and output impedances. With a dual-bias configuration, the amplifier possesses the characteristics of 30.4dB small-signal gain and 34dBm 1-dB gain compression power with 37.1% power added efficiency. Moreover, with a single carrier output power level of 24dBm, high linearity with a 43.5-dBm third-order intercept point operating at 3.5GHz is also achieved.

A four-stage Ku-band 1 watt PHEMT MMIC power amplifier

In this paper, a Ku-band 1 watt AlGaAs/InGaAs/GaAs PHEMT MMIC power amplifier for VSAT ODU (outdoor unit) applications is demonstrated. This four-stage amplifier is designed to fully match for a 50 ohm input and output impedance. With 7 V and 700 mA DC bias condition, the amplifier has achieved 30 dB small-signal gain, 30.8 dBm 1-dB gain compression power with 24.5% power-added efficiency (PAE) and 31.3 dBm saturation power with 27.5% PAE from 14 to 17 GHz.

Reactive ion etching technique for via-hole applications in thick GaAs wafers

The dry etching technique has been developed to etch via holes through a 5-mil-thick GaAs wafer by rf power and reactive gas pressures in a reactive ion etching system. The etching parameters are optimized for a slope profile suitable for power field effect transistors and monolithic microwave integrated circuit applications. The selectivity between GaAs and photoresist and the average etching rate can be higher than 30 and 1.1μm∕min, respectively. Furthermore, the slope angle measured from the vertical is larger than 11°, which is well suited for a thick GaAs via-hole etching process. Before the metal for the via-hole substrate is sputtered, the wet chemical etching solution based on HCl–H2O2∕H2O at room temperature is used to smooth the sidewall for a better connection. To probe these source pads, the via-hole resistances of the pseudomorphic high electron mobility transistors (PHEMTs) are measured to be less than 0.5Ω with more than 97.2% yield in a 4in. diameter GaAs wafer. It is found that the rf per...

A fully matched 8W X-band PHEMT MMIC high power amplifier

A X-band 8-watt AlGaAs/InGaAs/GaAs PHEMT MMIC power amplifier for the active phase radar applications is demonstrated. This amplifier is designed to fully match 50 ohm input and output impedance. With 8 volts and 850 mA DC bias condition, 17.5 dB small-signal gain, 39.3 dBm (8.5 watt) 2-dB gain compression power with 33.7% power-added efficiency and 40 dBm (10 watt) saturation power from 9.3 to 10.4 GHz can be achieved.

High performance 12 GHz enhancement-mode pseudomorphic HEMT prepared by He plus reactive ion etching

Abstract An enhancement-mode pseudomorphic high electron mobility transistor using optimum reactive ion etching (RIE) technology without damaging 2-D channel has been developed, at the first time. By using the optimum RIE recipe, the selectivity between GaAs and AlGaAs is more than 150. In addition, the maximum transconductance of the device with the dimension of 300 μm ×0.4 μm reaches 235 ms/mm at Vds=1.4 V. Furthermore, at 12 GHz, the output power and gain can achieve 17.9 dBm and 14.03 dB respectively. Operating at 12 GHz, the noise figure at Vds=4 V is down to 0.65 dB which is comparable to low noise depletion-mode device.

High-performance, low-noise enhancement-mode pseudomorphic high-electron-mobility transistor with gate recession by citric acid/hydrogen peroxide selective etching

An enhancement-mode pseudomorphic high-electron-mobility transistor (E-PHEMT) using a citric acid/hydrogen peroxide etching solution for gate recession is developed. The etch selectivity between GaAs and Al0.2Ga0.8As is more than 165 at 22°C, while the maximum transconductance for the fabricated device with the gate dimension of 160×0.25μm2 reaches 502mS∕mm at Vds=2.7V. Furthermore, at 12GHz, the 1dB compression output power and gain can reach 13.2dBm and 17.9dB, respectively. Operating at 12GHz, the minimum noise figure at the bias conditions of Vds=2V and Ids=11mA decreases to 0.45dB with the associated gain of 12.95dB, which is comparable to, or even better than that of, reported low-noise depletion- or enhancement-mode PHEMT devices. The standard deviation of the pinch-off voltage for the E-PHEMT across a 4in. diameter wafer could be as low as 50mV.An enhancement-mode pseudomorphic high-electron-mobility transistor (E-PHEMT) using a citric acid/hydrogen peroxide etching solution for gate recession is developed. The etch selectivity between GaAs and Al0.2Ga0.8As is more than 165 at 22°C, while the maximum transconductance for the fabricated device with the gate dimension of 160×0.25μm2 reaches 502mS∕mm at Vds=2.7V. Furthermore, at 12GHz, the 1dB compression output power and gain can reach 13.2dBm and 17.9dB, respectively. Operating at 12GHz, the minimum noise figure at the bias conditions of Vds=2V and Ids=11mA decreases to 0.45dB with the associated gain of 12.95dB, which is comparable to, or even better than that of, reported low-noise depletion- or enhancement-mode PHEMT devices. The standard deviation of the pinch-off voltage for the E-PHEMT across a 4in. diameter wafer could be as low as 50mV.

A 3.3 V self-biased 2.4-2.5GHz high linearity PHEMT MMIC power amplifier

A 3.3V single voltage self-biased 2.4GHz-2.5GHz high linearity AlGaAs/InGaAs/GaAs PHEMT MMIC power amplifier for wireless local-area network (WLANs) applications (dual channel for 802.11a/b combination systems)is demonstrated. This two-stage amplifier is designed to fully match for a 50 ohm input and output impedance. In this process, a backside via-ground method is not used, so it can offer very low cost for the production of wireless LAN IC. With only a 3.3V drain voltage, the amplifier has achieved 30dB small-signal gain, 23.5dBm 1 dB gain compression power with 24.2% power-added efficiency (PAE). In addition, high linearity with 37.2dBm third-order intercept point at frequency of 2.45GHz is achieved. For this power amplifier MMIC, the WLAN requirements of power amplifiers including aspects of high efficiency, high gain, high linearity and operation at 2.4GHz ISM band are procured.

A 3.5GHz 2W MMIC power amplifier using AlGaAs/InGaAs/GaAs PHEMTs

A 3.3-3.8GHz 2W MMIC power amplifier using AlGaAs/InGaAs/GaAs PHEMT for wireless local-area network and multi-channel multipoint distribution service applications is demonstrated. This two-stage amplifier is designed to match fully a 50/spl Omega/ input and output impedance. With dual-bias configuration, the amplifier possesses a 30.4dB small-signal gain, and a 34dBm 1-dB gain compression power with 37.1% power-added efficiency. Moreover, high linearity with a 41.5dBm third-order intercept point at a frequency of 3.5GHz is obtained.

High linearity power amplifier for PHS base station using a 50 mm AlGaAs/InGaAs/GaAs PHEMT

A high linearity, high efficiency 1.9 GHz power amplifier sub-system using a 50 mm AIGaAs/InGaAs/GaAs PHEMT for PHS 500 mW base station is demonstrated. Under 10 V and 3.8 A bias condition, the output stage amplifier has achieved 12.5 dB small-signal gain, 43.7 dBm PldB with 43% PAE and 44 dBm saturated output power with 41% PAE. For the amplifier sub-system, the ACPR at 600 KHz and 900 KHz offset from 1.906 GHz when operating at 38.5 dBm output power with /spl Pi//4-DQPSK signal are better than 75 dBc and 79 dBc, respectively.

L-band, high efficiency 25 watt power amplifier using PHEMT for base station system

In this paper, a 1.9 GHz watt high power amplifier using AlGaAs/InGaAs/GaAs PHEMT device for PHS base station applications is demonstrated. This amplifier utilizes a pre-matched FET which is composed of only a single 50 mm FET device and a MIS capacitor in a CuW flange package with other matching circuits on the FR4 PCB. Under 10 Volts and a 4 A dc bias condition, the amplifier has achieved 12.5 dB small-signal gain, 43.7 dBm 1 dB gain compression power with 43% power-added efficiency (PAE) and 44 dBm saturated output power with 41% PAR. In addition, high linearity with 53 dBm third-order intercept point is achieved. The ACP at 600 KHz offset from 1.906 GHz when operating at 39 dBm output power with /spl pi//4-DQPSK signal is better than 71 dBc.