Susumu Kamihashi

W-band SPST transistor switches

A single-pole, single-throw (SPST) transistor switch has been developed, Three types of switches, that is, GaAs MESFET, AlGaAs-GaAs HEMT, and pseudomorphic HEMT (PM-HEMT), have been fabricated, and the performances at W-band are compared. To reduce on-state resistance and off-state capacitance, gate length was varied as a parameter. Moreover, an inductance for resonance was installed in parallel to the off-state capacitance between source and drain to obtain a high isolation, A relatively low insertion loss of 1.6 dB and a high isolation over 20 dB at W-band have been obtained from the 0.8-μm gate length PM-HEMT.

Ka-band low loss and high power handling GaAs PIN diode MMIC phase shifter for reflected-type phased array systems

This paper describes the design and performances of a GaAs PIN diode and a reflected-type MMIC phase shifter in Ka-band. With optimized geometries and fabrication process, the GaAs PIN diode has shown the highest fmax so far. Excellent performances of MMIC phase shifters have also been obtained.

35% PAE 6 W Ku-band power amplifier module

Power amplifiers with 6 W output power in Ku- and X-band are demonstrated. The amplifier is a miniaturized hybrid module consisting of an MMIC and an internally matched FET which employs a DH-HEMT device technology. The amplifiers have exhibited PAEs of 35% and 45% in Ku and X bands.

New design of X-band GaAs MMIC phase shifter using improved equivalent circuit model

An improved yet simple equivalent circuit of a GaAs FET switch is proposed that takes parasitic distributed-line effects of the FET into account. X-band five-bit GaAs MMIC phase shifters designed using the model show a good agreement between the design and the measurement.<<ETX>>

C-band GaAs MMIC limiting power amplifier with small insertion phase variation

A C-band GaAs MMIC (monolithic microwave integrated circuit) limiting power amplifier has been developed by cascading three kinds of MMIC chips (a limiting amplifier, a gain-control amplifier, and a power amplifier) in a single package. It provides an output power of 33.2+or-0.2 dBm with an insertion phase variation of less than 2.3 degrees over an input power range of from 13.5 dBm to 18.5 dBm. The output power can be controlled between 17.8 dBm and 33.2 dBm with an insertion phase variation of less than 22.5 degrees.<<ETX>>

High-Power X-Band Mic Diode Phase Shifters

High-power X-band MIC diode phase shifters have been developed using glass-passivated PIN diodes with a grooved-mesa structure. Although they have outer dimensions of 20mm x 41mm x 10mm, they can handle 300W and 500W peak rf power depending upon the diodes used.