Effect of the microwave signal power on the controllability of a ferroelectric phase shifter

We consider a microwave phase shifter based on thin-film ferroelectric parallel-plate capacitors operating as a part of a phased array at an elevated microwave power level and for a limited power in the control circuits. To eliminate capacitance modulation in parallel-plate capacitors by an ac field, we propose the separation of the effects of the dc control voltage and the ac voltage based on the symmetry of the capacitance-voltage characteristic of the unit including two capacitors parallel-connected in the ac voltage $(U_{\mathrm{ac}})$ and series-connected in dc voltage $(U_{\mathrm{dc}})$. The experiment shows that for $(U_{\mathrm{dc}})>(U_{\mathrm{ac}})$, the phase of the wave passing through the phase shifter weakly depends on the microwave signal power. The reflection phase shifter is tested for a pulsed power of the microwave signal up to 6 W and a power in the control circuit on the order of 10 $\mu$W.