Taketo Kunihisa

A high performance GaAs MMIC transceiver for personal handy phone system (PHS)

A high performance GaAs MMIC transceiver has been developed for the Personal Handy phone System (PHS), Japans digital cordless telephone system. The MMIC includes a T/R switch, a Low Noise Amplifier (LNA) and a Power Amplifier (PA), which offers significant advantages in RF performance in comparison with silicon devices. In receive mode, the power gain and the noise figure including T/R switch are 15 dB and 2.4 dB, respectively. In transmit mode, the MMIC including T/R switch exhibits an overall power added efficiency (PAE)-of 25.5% and produces an output power of 21 dBm with an adjacent channel leakage power (Padj) of ¿56.2 dBc (600 kHz offset) at 1.9 GHz for ¿/4-shift QPSK modulated signal. A very small chip size of 1.0 mm × 2.7 mm is also realized. This is one of the smallest GaAs MMICs that have been reported with the same functionality.

A low noise and low power dissipation downconverter MMIC for DBS applications

In this work, using 0.2 /spl mu/m GaAs modulation doped FET (MODFET) technology, a high performance DBS downconverter MMIC was developed for direct broadcasting satellite (DBS) applications. Without an LNA, the downconverter MMIC showed a very low noise of 4.8 dB, which is 5 dB lower than conventional circuits. A low LO power of -10 dBm was required for normal DBS operation of the downconverter MMIC, which reduced the power consumption to 175 mW via removal of the LO amplifier on the MMIC. The LO leakage power at IF output was suppressed to a level lower than -30 dBm, which removes a bulky LO rejection filter from the board. The fabricated chip, which includes a mixer, IF amplifiers, and LO rejection filter, exhibits a small size of 0.84/spl times/0.9 mm/sup 2/.