WT4 Millimeter Waveguide System: Semiconductor Devices for the WT4 Repeater

Three new solid-state diodes were developed to generate, modulate, and down-convert millimeter-wave signals over the 40-110 GHz WT4 band. Silicon IMP ATT diodes generate the transmitter and local oscillator power, a silicon PIN switching diode phase-modulates the transmitted power, and a gallium arsenide Schottky-barrier mixer diode downconverts the signal in the receiver. Also, numerous other devices were either specifically developed for or found usage in WT4. These devices operate in the IF (1.371 GHz) or baseband (dc to 300 MHz) circuitry. 2119 T a b l e I -- W T 4 s y s t e m r e q u i r e m e n t s f o r IMPATT d i o d e s Frequency, GHz 43 50 59 70 80 90 105 Power output, mW 24phase phase 170 130 100 75 55 45 35 340 260 200 150 110 90 70 Efficiency, f Figure of merit* percent 2424phase phase phase phase 4.3 4.1 4.0 3.8 3.6 3.3 2.9 6.4 6.1 5.8 5.5 5.2 4.9 4.5 173 173 173 173 86 86 86 86 86 86 86 43 43 43 Thermal impedance, °C/W 30 40 55 70 84 97 112 Total capacitance, pF 0.41 0.35 0.30 0.25 0.21 0.19 0.17