Citation
Abstract
A phase modulator capable of large linear phase deviation, low loss, and wideband operation with good thermal stability has been developed for deep space spacecraft transponder (DST) applications at X-band (8.415 GHz) and Ka-band (32 GHz) downlinks. The design uses a two-stage circulator-coupled reflection phase shifter with constant gamma hyperabrupt varactors and an efficient modulator driver circuit to obtain a phase deviation of +2.5 rad with better than 8 percent linearity. The measured insertion loss is 6.6 dB +0.35 dB at 8415 MHz. Measured carrier and relative sideband amplitudes resulting from phase modulation by sine wave and square modulating functions agree well with the predicted results.
Details
- Volume
- 42-112
- Published
- February 15, 1993
- Pages
- 107–116
- File Size
- 357.4 KB