Chian Sern Chang

An X-Band High-Power and High-PAE PHEMT MMIC Power Amplifier for Pulse and CW Operation

An X-band high-power and high power added efficiency (PAE), two-stage AlGaAs/InGaAs/GaAs psuedomorphic high electronic mobility transistor (PHEMT) monolithic microwave integrated circuit (MMIC) power amplifier is presented. The amplifier is designed to fully match a 50 Omega input and output impedance. Based on a 0.35 mum gate-length power PHEMT technology, the MMIC is fabricated on a 3 mil thick wafer. Under an 8 V DC bias condition, the characteristics of 17.5 dB small-signal gain, 10 W continuous wave mode saturation output power of 42% PAE, and 12.6 W pulse saturation output power of 52.6% PAE at 9.4 GHz can be achieved.

A 9.1–10.7 GHz 10-W, 40-dB Gain Four-Stage PHEMT MMIC Power Amplifier

This letter presents a compact X-band high gain and high power four-stage AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) monolithic microwave integrated circuit (MMIC) high power amplifier (PA). This amplifier is designed to fully match a 50-Omega input and output impedance. Based on 0.35-mum gate-length power PHEMT technology, this PA MMIC is fabricated on a 3-mil thick wafer. While operating under 8 V and 2700-mA dc bias condition, the characteristics of 40-dB small-signal gain, a 10-W continuous-wave saturation output power, and 33% power added efficiency at 9.7GHz can be achieved

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 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.

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 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, Vds= 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

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.

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.