Title :
Reducing the gain and phase variation in high power MMW TWTs
Author :
Limburg, H.C. ; Davis, J.A. ; Tammaru, I. ; Vaszari, J.P. ; Wilson, J.
Author_Institution :
Hughes Aircraft Co., Torrance, CA, USA
Abstract :
A study was performed to minimize the signal distortion of high-power MMW (millimeter wave) communication TWTs (traveling wave tubes) in satellite uplinks. The effect of TWT design parameters on small-signal gain variation was first evaluated analytically. Three PPM (pulse position modulation)-focused Ka-band TWTs were then designed and built to evaluate distortion-reduction techniques. TWTs which featured a ferruleless cylindrical coupled-cavity circuit demonstrated the performance objective of 400 W of saturated output power and 50-dB gain over the 29-30-GHz band. The parabolic small-signal gain variation was less than 3 dB, and the small-signal gain ripple was 1 dB or less, a marked improvement for these types of TWTs. The TWTs´ performance and the techniques used to reduce the amplitude variations are discussed.<>
Keywords :
satellite relay systems; telecommunication equipment; travelling-wave-tubes; 29 to 30 GHz; 400 W; 50 dB; Ka-band TWTs; PPM; amplitude variations; communication TWTs; design parameters; ferruleless cylindrical coupled cavity circuit; high power MM-wave TWTs; phase variation; satellite uplinks; saturated output power; signal distortion; small-signal gain ripple; small-signal gain variation; Aircraft; Circuits; Electrons; Frequency; Gain; NASA; Nonlinear distortion; Power generation; Signal design; Voltage;
Conference_Titel :
Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International
Conference_Location :
San Francisco, CA, USA
DOI :
10.1109/IEDM.1988.32836
