Minimizing passive intermodulation product generation in high power satellites

The evolution of high power multi-channel communication and direct broadcast (DBS) satellites with transmit and receive functions combined into a single antenna typically result in a source of interference which must be controlled. This source of interference is passive intermodulation products (PIMs) which are formed when two transmit carriers beat together to generate harmonics that fall into the receive band. This paper describes how PIMs were initially generated in high power Ku-band antennas on the Intelsat VIIA satellite program and the extraordinary methods used to suppress them. The method used to measure PIM levels is described and the test data results that demonstrate the performance achieved is given.