English title

Separated Turnstile (ST) Antenna has many applications in small Low Earth Orbit (LEO) satellites. Ability of dual-band operation and circular polarization are the main features of this antenna. The purpose of this paper is design and analysis of a Separated Turnstile antenna, which can work in UHF and VHF band simultaneously. The antenna has saddle-shaped radiation pattern in UHF band for data and message communications and omni-directional pattern in VHF band for Control and monitoring of the satellite especially in the case that the antenna is not oriented to the earth.

The antenna model is analyzed by using moment method. Effects of satellite body on the radiation pattern are studied in this paper.

 For the antenna optimization, analysis is iterated and results are compared with the desired results. Antenna’s physical parameters are changed in each stage and iteration is continued until the proper result is achieved.

Engineering model of the antenna which is mounted on the satellite is constructed and its radiation properties are measured. In the final section, test results are compared with analysis results and validity of the design is confirmed.