Low cost S-band phase modulator for modern TTC application

Abstract

This paper describes the design, simulation and practical results of a phase modulator based in an hybrid coupler and two varactor diodes in the band from 2.0 GHz to 3.0 GHz for TTC proposes. A minimum modulation index of 1.22 was obtained at the highest frequency to 1.57 at the lowest. This modulator consist of a two stages hybrid coupler with varactor diodes. Simulation is performed using ADS 2016.01. Even both varactor diodes are feed by the same modulation signal, each of them has his own voltage input for correct varactor impairments. In the measures, excellent isolation is achieved for the 1st and 4th port of the ring.