In this paper, we present the development of an advanced MMIC receiver for a 94-GHz band passive millimeter-wave (PMMW) imager. Our configuration is based on a Dicke receiver in order to reduce fluctuations in the detected voltage. By introducing an electronic switch in the MMIC, we achieved a high resolution millimeter-wave image in a shorter image collection time compared to that with a conventional mechanical chopper. We also developed an imaging array using MMIC receivers.

The heterogeneous integration of GaAs HEMTs on a polyimide-covered AlN ceramic substrate was demonstrated using a fluidic self-assembly (FSA) technique. We used thin device blocks for the FSA, which have various advantages. In particular, they can reduce the drain-source capacitance Cds of the assembled HEMTs if the substrate has a low dielectric constant. This is a novel kind of semiconductor-on-insulator (SOI) technology. The dc and RF properties of the GaAs HEMTs on the polyimide/AlN substrate were studied and the reduction of Cds was confirmed. This technique was successfully applied to the SPDT switch, where a low Cds is essential for good isolation.

Two types of p-i-n diode devices, namely an amplitude shift keying switch and a phase shift keying switch, were developed by using an NRD guide at 77 GHz. In order to apply these devices to radar systems, an SPDT switch with a low insertion loss of less than 2.5 dB and a high isolation of more than 25 dB was fabricated by using the former switch. Moreover, a BPSK modulator, composed of the latter switch together with a circulator and a ceramic resonator loaded band-pass filter, was designed and evaluated for use in spread spectrum radar systems in this frequency range.

A GaAs SPDT switch IC operating at a low power supply voltage of 2.7 V has been developed for use in 1.9 GHz band personal handy phone system (PHS). In combination with MESFETs with low on-resistance and high breakdown voltage, the switch IC adopts parallel-LC resonant circuits and utilizes both stacked FETs and an additional shunt capacitor at the receiver side in order to realize low insertion loss, high isolation and low distortion characteristics. An insertion loss of 0.55 dB and an isolation of 35.8 dB were obtained at 1.9 GHz. The IC also achieved an output power of 25.0 dBm at 1 dB gain compression point, a second order distortion of -54.3 dBc and an adjacent channel leakage power of -66 dBc at 600 kHz apart from 1.9 GHz at 19 dBm output power.