A planar 94-GHz transceiver with switchable polarization

The design and performance of a low-cost, planar microstrip 94-GHz transceiver is described. It includes a two-axis, monopulse-fed, four-element, switchable, right-hand-left-hand circularly polarized patch antenna. All circuits are monolithic microwave integrated circuits (mixer, intermediate-frequency amplifier, and RF PIN diode switch) interconnected with low-loss, Z-cut quartz microstrip. The miniature 1.1-in-diameter by 0.25-in-thick transceiver operated both in the transmit and in the receive mode with a 3-dB beamwidth of 58 degrees . When mounted as a feed for a 5-in-diameter parabolic dish, the assembly exhibited a 1.7 degrees 3-dB beamwidth, 12-dB sidelobes, a gain of 26 dB, and a difference pattern null of 30 dB. >