HIGH PEAK POWER DIFFERENTIAL PHASE SHIFT CIRCULATOR

摘要

Differential phase shift circulators can operate at high peak power levels, provided the power level is below the threshold at which non-linear phenomena occur. These phenomena appear as the result of the excitation of the spin waves in the ferrimagnetic material. A differential phase shift version of circulator with two 3 dB couplers and a section with double phase shifter was manufactured in an H-waveguide operating in the 9-10 GHz frequency range at a power level higher than that accepted by the R100 waveguide. The circulator consists of two 3 dB Riblet couplers, a phase shift section and a differential phase shift section. A cobalt doped yttrium iron garnet with a controlled porosity was employed as ferrimagnetic material. The ferrimagnetic material was double calcined, then sintered at 1270 C. A decrease in total porosity, though an increase in open porosity and in pore radius with the sintering temperature (T_S) increase was observed. It was found that the controlled porosity could be a means of controlling the ferrimagnetic bar resistance to thermal shocks. Finally, the high peak power differential phase shift circulator exhibited an insertion loss less than 0.5 dB and a return loss and an isolation greater than 20 dB in the range from 9.1 to 9.8 GHz.