We developed a 300-GHz high gain amplifier MMIC in 75-nm InP high electron mobility transistor technology. We approached the issues with accurate characterization of devices to design the amplifier. The on-wafer through-reflect-line calibration technique was used to obtain accurate transistor characteristics. To increase measurement accuracy, a highly isolated structure was used for on-wafer calibration standards. The common source amplifier topology was used for achieving high gain amplification. The implemented amplifier MMIC exhibited a gain of over 25 dB in the 280-310-GHz frequency band.

A wide-bandwidth fundamental mixer operating at a frequency above 110GHz for precise spectrum analysis was developed using the InP HEMT technology. A single-ended resistive mixer was adopted for the mixer circuit. An IF amplifier and LO buffer amplifier were also developed and integrated into the mixer chip. As for packaging into a metal block module, a flip-chip bonding technique was introduced. Compared to face-up mounting with wire connections, flip-chip bonding exhibited good frequency flatness in signal loss. The mixer module with a built-in IF amplifier achieved a conversion gain of 5dB at an RF frequency of 135GHz and a 3-dB bandwidth of 35GHz. The mixer module with an LO buffer amplifier operated well even at an LO power of -20dBm.

Second harmonic signal feedback technique is applied to an HBT power amplifier for Wide-band CDMA (W-CDMA) mobile communication system to improve its linearity and efficiency. This paper describes the feedback effect of the 2nd harmonic signal from the output of the amplifier to the input on the 3rd order intermodulation distortion (IMD) products and Adjacent Channel leakage Power (ACP) of the power amplifier. The feedback amplifier, using an InGaP/GaAs HBT with 48 fingers of 3 20 µ m emitter, exhibits a 10 dB reduction in the level of the 3rd order IMD products. In addition, an ACP improvement of 7 dB for the QPSK modulation signal with a chip rate of 4.096 Mcps at 1.95 GHz was realized. As a result, the amplifier achieves a power-added efficiency of 41.5%, gain of 15.3 dB, and ACP of 43.0 dBc at a 5 MHz offset frequency and output power of 27.5 dBm. At the output power of 28 dBm, the power-added efficiency increases to 43.3% with an ACP of 40.8 dBc.

We report on robust and low-power-consumption InP- and GaN-HEMT Low-Noise-Amplifiers (LNAs) operating in Q-band frequency range. A multi-stage common-gate (CG) amplifier with current reuse topology was used. To improve the survivability of the CG amplifier, we introduced a feedback resistor at the gate bias feed. The design technique was adapted to InP- and GaN-HEMT LNAs. The 75nm gate length InP HEMT LNA exhibited a gain of 18dB and a noise figure (NF) of 3dB from 33 to 50GHz. The DC power consumption was 16mW. The Robustness of the InP HEMT LNA was tested by injecting a millimeter-wave input power of 13dBm for 10 minutes. No degradation in a small signal gain was observed. The fabricated 0.12µm gate length GaN HEMT LNA exhibited a gain of 15dB and an NF of 3.2dB from 35 to 42GHz. The DC power consumption was 280mW. The LNA survived until an input power of 28dBm.