Passive non-linearities in antenna systems

The paper is based on the results of a wide-ranging literature search and the experience the authors have gained in passive intermodulation products (PIMP) measurements over the last two years. The purpose is to give an overview of recent research relative to the investigation of PIMP in antenna systems. It describes briefly the types of passive non-linearities, mechanisms responsible for the generation of PIMP, guidelines for minimising PIMP generation, techniques for locating passive non-linearities, analysis of higher order PIMP and the study of various types of components, including feeders, reflectors, feeds, multicouplers and duplexers