A 75 GHZ TO 115 GHZ QUASI-OPTICAL AMPLIFIER

A wideband quasi-optical amplifier employing two pyramidal back-to-bac k horns has been developed. Using a four-stage W-band low noise amplif ier (LNA) designed and fabricated by Martin Marietta Laboratories, the quasi-optical amplifier gives a system gain greater than 11 dB from 8 6 GHz to 113 GHz without any low frequency oscillations. A peak system gain of 15.5 dB is measured at 102 GHz, and the measured noise figure of the system is 7.4 dB at 94 GHz. The quasi-optical amplifier design maintains the same polarization of the received and transmitted signa l, provides better than -40 dB isolation, and can be fabricated monoli thically at millimeter-wave frequencies.