Passive tritium-primed TR-limiters for X and Ku-band

Passive TR-limiters were developed for X and Ku-band using tritium foils as priming electron sources to lower breakdown power of the gas discharge TR tube. Single stage varactor limiters were mounted three quarters of a guide wavelength behind the primed gap to provide a voltage maximum at the gap. Breakdown power was, found to be only weakly dependent on pulse repetition rate (PRR) indicating that the net priming electron density provided by the tritium source was greater than the residual electron density from previous high power pulses. The effectiveness of tritium priming was demonstrated with a bellows mounted source which could be moved in and out of the TR tribe, Breakdown power varied as the square of the distance from the primed gap. Minimum breakdown power of the TR portion of the package was about 250 mW at a PRR of 150 PPS. This is a 10 dB improvement over the previously reported value (1). The corresponding leakage power from the TR-limitter package prior to TR breakdown did not exceed 20 mW. Spike leakage energy was less than 01 ergs over a temperature range of--55° to 125°C. Insertion loss was less than 0.8 dB.