GaAs FET direct frequency-modulators for 42-GHz-band HDTV radio cameras and 7-GHz-band field pick-up transmitters

Abstract

This paper describes the dcsign of a dircct frequcncymodulator with high modulation sensitivity. With a diclcctric resonator, two hyper-abrupt-junction varactors, and a GaAs FET, this design achieves a modulation scnsitivity greater than 20 MHz/V in a 42-GHz-band frcqucncy-modulator developed for HDTV radio cameras. When this design is used in a 7-GHz-band frequency-modulator for a ficld pick-up transmittcr gathering cmcrgency news, it provides an output power of 22 dBm, a differential gain of less than 396, and a differential phase of less than 2". All transmitters using this new frcquency-modulator havc high broadcast cfficicncy .

60-GHz-band ultracompact transmitter for HDTV

“…Figure 3 shows the schematic diagram of the modulator. To obtain high-modulation sensitivity, we used two hyperabrupt-junction-varactor diodes on both ends of a microstrip line, which is magnetically coupled to the dielectric resonator [6]. Figure 4 shows the modulation characteristics of the modulator.…”

“…In order to make a transmitter that is small, light, and low power consumption, we used microwave-band direct frequency modulators [6], MMIC multipliers and amplifiers, and integrated-microstrip-planar antennas. This paper describes an outline of the transmitter's design, performance, and applications.…”