High Average Power S-Band Digital Phase Shifter

A 100-kW-peak Z-kW-average-power liquid-cooled ferrite digital phase shifter has been constructed using beryllia cooling of the ferrite toroid to meet single axis scanned array requirements. The phase-shift cross section external to the ferrite toroids is completely filled with the beryllia. Experiments indicate that the maximum temperature rise in the ferrite is no greater than 45/spl deg/ C. In tests using flux drive to 2 kW, the phase shifter exhibits a maximum phase drift of /spl plusmn/ 6/spl deg/ for 90/spl deg/ differential phase shift. The differential phase shift versus frequency varies less than /spl plusmn/ 0.5/spl deg/ for a 3-percent bandwidth.