SSEEM-An Innovative Spread Spectrum System For Satcom Antenna Radiation Pattems Measurements

This paper describes an innovative system, named SSEEM, for co-polar and cross-polar radiation pattern measurements of earth station antennas. The SSEEM system is based on highly spread spectrum waveforms and, due to its high processing gain (PG), is able to overcome the limitations of the conventional approach used by satellites operators, based on transmitting a high-power continuous wave (CW). Indeed, the SSEEM system can operate in very low carrier-to-noise plus interference ratio regions (around -56dB for 72 MHz bandwidth). Consequently, it does not cause interference on adjacent satellites nor with a signal present within the satellite transponder used for the measurement. This means such tests can be carried out in any moment, without the need for a free satellite slot for transmission. In addition, the high PG allows for resolving even far side lobes of the antenna radiation patterns, without increasing transmission power, as in the CW case.