Performance results of a 300 degrees linear phase modulator for spaceborne communications applications

Author

Mysoor, N.R. ; Mueller, R.O.

Author_Institution

Jet Propulsion Lab., California Inst. of Technol., Pasadena, CA, USA

fYear

1993

fDate

Jan. 31 1993-Feb. 5 1993

Firstpage

43

Lastpage

52

Abstract

A phase modulator capable of large linear phase deviation, low loss, and wideband operation with good thermal stability is described. The phase modulator was 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 +or-2.5 rad with better than 8% linearity. The measured insertion loss is 6.6 dB+or-0.35 dB at 8415 MHz. It is shown that measured carrier and relative sideband amplitudes resulting from phase modulation by sinewave and square modulating functions agree well with the predicted results.<>

Keywords

microwave links; modulators; phase modulation; phase shifters; space communication links; transponders; Ka-band; X-band; carrier; constant gamma hyperabrupt varactors; deep space spacecraft transponder; downlinks; driver circuit; insertion loss; linear phase deviation; linear phase modulator; relative sideband amplitudes; sinewave modulating functions; spaceborne communications; square modulating functions; thermal stability; two-stage circulator-coupled reflection phase shifter; Circuit stability; Downlink; Phase modulation; Phase shifters; Reflection; Space vehicles; Thermal stability; Transponders; Varactors; Wideband;

fLanguage

English

Publisher

ieee

Conference_Titel

Aerospace Applications Conference, 1993. Digest., 1993 IEEE

Conference_Location

Steamboat, CO, USA

Print_ISBN

0-7803-0980-4

Type

conf

DOI

10.1109/AERO.1993.255335

Filename

255335