Modelling and Simulation of Onboard Wire Antennas for a 3U CubeSat

This paper discusses the results obtained and conclusions made from modelling and simulation of the on-board antennas for a 3U CubeSat being developed by Team Anant, a group of undergraduate students at BITS Pilani. The nanosatellite features a hyperspectral camera as its primary payload. The paper initially documents the reasons for selection of a turnstile antenna for downlink in the 435 MHz band of the UHF region, and a monopole for uplink in the 144 MHz band of the VHF region. Ansys High Frequency Structural Simulator (HFSS) has been used to carry out parametric simulations for desirable network matching, radiation pattern and directivity. Further, the effect of the metallic structure of the CubeSat is examined for optimization of antenna parameters. The rationale for arriving at two particular positions for the antennas on the CubeSat is elucidated based on electromagnetic compatibility (EMC). Two different positions for the antennas are arrived at and a comparative analysis is provided. Simulations and results are also presented on the mutual interaction of the two different antennas. It is important to design, model and simulate an antenna using electromagnetic CAD tools, especially for low cost CubeSat projects. The paper is an attempt to provide nano-satellite missions with a systematic strategy for modelling and analysing wire antennas.