Time-division multiplexing monopulse antenna system for DVB-SH application

This study involved developing a time-division multiplexing monopulse antenna system for tracking the DVB-SH signal operated in S-band. Such a system consists of a mode-former circuit and a stacked circularly polarized antenna array, which was implemented using planar-printed circuit technology. In the mode-former circuit, a four-way power splitter comprising Wilkinson power dividers and four switched-line phase shifters were employed to provide 0°/180° phase angles at each output port. The sum-and-difference angle discriminators were implemented along vertical and horizontal planes for detecting the incident elevation and azimuth angles. The stacked circularly polarized antenna array, composed of four edge-fed patches on the bottom layer and four corresponding parasitic patches, were exploited on the top layer to increase the axial ratio bandwidth. The experimental results revealed that, at 2.185 GHz, the null depth of the difference patterns were -34.2 dB and -33.2 dB along the two principal planes.