| Popis: |
This paper describes a new type of microwave coaxial gas switch tube which utilizes an electronically controlled pulsed hydrogen arc discharge. The device fires in a few tenths of a microsecond and recovers in a time of the order of 10 microseconds. It covers a frequency range extending from below 1 Gc/s to above 4 Gc/s. The tube operates over a wide range of pulsed peak input powers, from microwatts to hundreds of kilowatts, depending upon the particular application. Its unfired insertion loss and its arc loss are of the order of 0.1 db and 1 db respectively and its leakage isolation exceeds 50 db. The tube consists of a section of 7/8" coaxial line sealed off at each end by ceramic windows. Portions of the inner and outer conductors are gridded and together with a heated cathode and an anode provide an electrode structure similar to that in conventional hydrogen thyratrons. A number of tubes utilizing different electrode structures have been built and tested and are described. Switching is accomplished by creating an arc between the electrodes. Upon application of a trigger voltage, a previously charged pulse forming network discharges through the tube, The resultant electron density is of the order of 1012per cm3and acts like a short circuit to the incident microwaves. The results of measurements of the switch's firing time, recovery time, insertion loss, leakage, holdoff power and noise figure at both L and S-bands are presented and discussed. |
