GaAs monolithic image rejection down-converter for point-to-multipoint communication systems

A fully integrated GaAs monolithic image rejection downconverter for L/S band operation is presented. All the necessary subcircuits such as RF splitter, LO (local oscillator) phase shifter, two mixers, and its biasing circuits are included on a GaAs chip. Only an IF (intermediate frequency) hybrid is needed as external component. Experimental results verify the operation of the device, showing more than 20 dB of image rejection, 8 dB gain conversion, 30 dB LO to IF isolation, and 20 dB LO to RF isolation throughout the operating band. The MMIC (monolithic microwave integrated circuit) contains 18 MESFETs and 40 passive components in a 1.2*3 mm/sup 3/ area.<
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