S-Band Transceiver Antenna for Telemetry and Telecommand Applications

Abstract

In this article, a novel compact, single-fed circularly polarized transceiver patch antenna is designed and developed for Telemetry, Tracking, and Command (TT&C) applications. Conventionally two distinct antennas are required for TT&C functionality, but the proposed solitary patch antenna accomplishes both tasks by reducing power, cost, antenna weight, and placement complexity. Since TT&C requires isotropic coverage, a Quadrifilar Helical antenna is placed on the earth-facing side, while the proposed antenna is mounted on the non-earth facing side and serves as a null filling antenna for the microsatellite developed by the PES University. The antenna consists of a diagonally fed radiating patch with two circular radiators stacked on top of each other with spacers to achieve 13.5% wider bandwidth for uplink (2.025-2.11 GHz) and downlink (2.2-2.29 GHz) applications. The simulated result shows that the antenna achieves a good impedance matching and axial ratio by covering a wide impedance bandwidth of 370 MHz, a wide beamwidth of 120° and cross-polarization isolation of 15dB. The antenna is fabricated using space-qualified material and tested along with the satellite structure at DARE, DRDO, Bangalore. It is also robust and can withstand thermal shock and vibration. Experimental validation shows that the simulated results agree well with the measured results.