Three-chip transceiver

Mimix Broadband has introduced a GaAs monolithic microwave integrated circuit 13/15 GHz chip set that consists of a highly integrated image reject receiver and transmitter, and compact, two-stage power amplifier.

The image reject mixers eliminate the need for an image bandpass filter after the amplifier to remove thermal noise at the image frequency.

The chip lowers costs and variability of transceivers by using fewer parts, a smaller footprint area and a simpler design. The devices are suitable for wireless communications applications such as millimetre-wave point-to-point radio, local multipoint distribution services (LMDS), SATCOM and VSAT applications.

The receiver uses an image reject resistive 'cold fet' fundamental mixer to provide wide bandwidth and good intermodulation performance. An image reject balanced mixer is used in the transmitter, or up-converter, to minimise spurious emissions and ease filtering requirements before the up-converted signal is fed to the compact single ended PA.

Linearity is suitable for the high order QAM modulation required in new radios to maximise spectrum usage. The useful bandwidth of the receiver and transmitter is 10 to 18 GHz, flat from 11 to 17 GHz, so they cover the commercial 13 and 15 GHz bands and intermediate satellite bands.