Precision L-Band Analog-Digital Phase Shifter with a 0°–360° Phase Change

Abstract

In modern satellite communication systems and airborne repeaters using an APAR, the receiving and transmitting modules usually consist of discrete phase shifters such as hybrid integrated circuits or monolithic circuits. In this paper, we consider an open-frame analog-digital phase shifter module with a 0°–360° phase change that allows ensuring the accuracy of setting the discrete phase to not more than 0.5° based on the domestic control UHF MIS varicaps. An original L-range analog-digital phase shifter with a 0°–360° phase change using a Lange bridge and phase-shifting cells based on four UHF MIS varicaps is proposed. The requirements for the type of volt-farad characteristic and the capacitance overlap coefficient of the MDP-varicap capacitance are determined. Even at the limiting (critical) UHF MIS-varicap frequency not higher than 15 GHz, the proposed scheme of the analog-digital phase shifter allows ensuring the phase shifter loss that is not greater than 1.5 dB in the L-band. The analog-digital phase shifter with a 0°–360° phase change was operated by the digital control board. An 8-bit DAC was used. The division value of the discrete control of the phase shifter is 1.4° at 256 DAC states. The obtained characteristics of the precision analog-digital phase shifter allow concluding on the propects of its use for solving synchronization problems of an active radio target simulator in testing synthetic aperture radars, as well as in the receiving and transmitting modules of a low-element APAR for the L-band.