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Fig.l. Schematics of the semiconductor switchAbstract-We investigate non-stationary problems of highpower microwaves penetrating into and reflecting from a semiconductor (silicon) plate. The plate is the base of switch activated by laser-driven photoconductivity and changing its properties when heated by the switched microwave power. Analytical criteria for the stationary solutions of the activated (quasi-metallic) and deactivated (dielectric) states of the switch under the conditions of high-power microwave heating and external cooling are found. Results of numerical simulations are also given for the problems of the switch activation by microwave heating initiated by pulsed laser radiation, which increases the carrier density rapidly. Numerical simulations are carried out by means of the finite-difference time-domain method with the unsplit perfectly matched layer absorbing boundary conditions. We demonstrate various types of solutions which depend on the basic parameters of the problem, namely, microwave field intensity, laser pulse energy and semiconductor doping..

We report the design and test of the transmission line for DNP spectrometer with 258GHz gyrotron. The 16 meter line includes mode converter, HE11 waveguides, 5 mitre bends, variable attenuator, directional couplers, calorimeter and switch.Transmission is 70 ± 15% with 15Watt in the pure HE11 mode.

Cylindrical waveguide with a helical corrugation on the inner surface has proven an effective dispersive medium for the compression of smoothly frequency modulated microwave pulses. This paper presents the results of experiments where -5.6kW, X-band (8. 0GHz to 12.5GHz), microwave pulses of 80ns duration and 5% frequency modulation were compressed into 1.5ns pulses with 25 times higher peakpower.

The task of many criteria choice of effective decisions is given in information-al transport system of any structure from the point of view of a system approach.