Toshikazu Hirai

A high-performance and miniaturized dual-use (antenna/local) GaAs SPDT switch IC operating at +3 V/0 V

We have developed an ultra-compact dual-use (antenna/local) switch IC for PHS operating at +3/0 V. This IC has a circuit configuration which utilizes MESFETs with two kinds of pinch-off voltages. Additional applied techniques include a circuit design method that employed electromagnetic field analysis, a pull-up method which utilizes forward current flowing in order through the gates of MESFETs, and high isolation characteristic obtained by use of a chip inductor. The insertion loss and isolation characteristics of this IC are, respectively, 0.54 dB and 28.4 dB at 1.9 GHz and 0.48 dB and 30.0 dB at 1.65 GHz. Furthermore, we were able to suppress adjacent channel leakage power to 61.5 dBc at 600-kHz offset during input power of 22 dBm QPSK modulated signals.

A super low-noise ion-implanted planar GaAs MESFET MMIC amplifier

In order to develop an ultra-compact and super low-noise MMIC amplifier for the receiving system of PHS, the input and output impedance of an ion-implanted planar GaAs MESFET were successfully reduced while maintaining its high-gain and low-noise characteristics. The MMIC had a noise figure of 1 dB and a gain of 13.5 dB at 3 V, 20 mA and 1.9 GHz in an ultra-compact plastic package. The fabricated switch and LNA module employing this MMIC has achieved the low-noise property of less than 3 dB.