Electromagnetic Analysis Of An Antenna Mounted On A Satellite Platform

By Matthys M. Botha and Ernst H. Burger, Altair Engineering Inc

Introduction

This article deals with the analysis of a complex antenna mounted on a satellite platform. The geometry of an Iridium satellite is considered, of which a constellation of 66 are at present employed in providing a global mobile communication service.

The first goal of this article is to demonstrate the use of computational electromagnetics (CEM) tools to analyse a large, L-band array antenna, which provides a ground coverage footprint to the satellite. This ground coverage antenna (GCA) closely resembles the Iridium main mission antenna (MMA) in terms of layout, but its detailed design dimensions are established independently. The Iridium system covers the whole surface of the earth with such footprints.

The second goal is to further analyse this antenna within its operating environment (i.e. mounted on the satellite frame). Such in situ analysis is of great interest when a system has to be reliable under all circumstances, with stringent quality requirements.

Along the way, EM analysis options and computational issues are discussed. The article gives readers an understanding of the present capabilities of CEM tools in relation to computational resources, when dealing with real-world aerospace applications. The EM simulation tool FEKO is used throughout.

An outline of the article is as follows. The satellite geometry is first presented. This is followed by a description and analysis of the microstrip patch antenna that forms the basis of the array. Next, the antenna array design and analysis is discussed. Finally, analysis of the full satellite with the mounted antenna array is considered.