Accurate and efficient platform scattering analysis for antennas mounted on satellites

21 Jan 2019

The ESTEAM product in TICRA Tools is routinely applied in the spacecraft industry to perform detailed platform scattering analysis of antennas mounted on satellites. The backbone of ESTEAM is our efficient higher-order Method of Moments (MoM) and Multi-Level Fast Multipole Method (MLFMM) solvers.

Convenient importing of CAD files

An entire satellite platform can be built inside TICRA Tools, but can also, more conveniently, be imported as a CAD file. All geometries need to be meshed as the first part of the analysis, which is handled automatically by the built-in mesher.

CAD files received from the mechanical department may contain details of such fine granularity, that it would not be meaningful to try to mesh. Additionally, the RF impact of these details – screws and screw holes, for example – would be insignificant from an RF point of view and should be excluded from the analysis. Therefore, any CAD file must be cleaned by the user before import. Below, a cleaned CAD file of a satellite is shown (left) together with the MoM mesh (right).

As an example, we consider one of the reflector antennas on the satellite shown above. It is fed by a corrugated horn, and we apply the MoM/MLFMM solver to the imported CAD file to get the currents on the entire platform. The below colour plot of the currents clearly suggest that the satellite bus and solar panels will influence the radiation pattern.

The reflector antenna is circularly polarized and has, for the isolated antenna, ideal left-hand circularly polarized (LHCP) and right-hand circularly polarized (RHCP) patterns shown below.

LHCP  (left) and RHCP (right) pattern from isolated antenna. 

When considering the installed antenna, a completely different sidelobe structure appears. It is of extreme importance for the manufacturer to be aware of this to take corrective action, if needed.

LHCP (left) and RHCP (right) patterns from antenna installed on satellite.

The above computations have been performed in Ka band, at a frequency of 30 GHz. The table below shows the electrical size of the platform scattering problem at this frequency and compares the number of unknowns resulting from using the higher-order MoM/MLFMM implementation in ESTEAM with a standard implementation based on the Rao-Wilton-Glisson approach.

Computational data for analysis at 30 GHz.

Minimum memory requirement and high computational speed

The efficient ESTEAM algorithms make it possible to solve the entire problem in 7 hours on a machine with an Intel Xeon processor and at least 380 GB of RAM. This speed and low memory use are superior to any other commercial software.

To see the real practical value of accounting for the interaction between the antenna and the spacecraft, both radiation patterns can be superimposed on a world-map plot as seen from the given satellite orbital position. This way, regions affected by unwanted sidelobes can easily be identified and further evaluated.

Ideal (red) and installed (blue) performance as seen on Earth from given orbital position.

Try the capabilitiies of ESTEAM

To experience the capabilities of ESTEAM, we offer a 30 days trial. Apply for a trial by sending an email to info@ticra.com.

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