Further development of a future ESM channeliser with high temperature superconducting filters

An important function of an Electronic Warfare Support Measures (ESM) receiver is the acquisition and identification of signals in the Electronic Warfare (EW) environment. Ideally the receiver requires a high probability of intercept. Current receiver types include wide open systems, which suffer from signal overlap, and scanning superheterodyne receivers, which have a low probability of intercept against some signals. The ideal solution is to channelise the search bandwidth with each channel monitored continuously. To obtain high frequency resolution many narrow bandwidth filters are required. If miniature conventional filter technology is utilised the insertion losses become unacceptably high. By using high temperature superconductors (HTS), a channeliser of small size and low loss may be realised. This paper describes the recent design and build of an ESM channeliser with potential for 2-18 GHz operation. It uses eight filter banks, each consisting of twenty superconducting filters with a bandwidth of 100 MHz, contained within a cryogenically cooled dewar. Interconnects from the filter banks to the external rf connectors consist of flexible microtrace circuits.