Superconducting filters for radio astronomy

Abstract

Superconducting filters provide extremely low loss and very sharp transitions from stop bands to pass bands and are therefore ideal for cutting out interference in a radio astronomy receiver. The collaborative work between the Jodrell Bank Observatory operated by the University of Manchester and the University of Birmingham has produced a range of filters operating in a number of observation bands between around 400 MHz and 8 GHz. Some of these filters have been tested in receivers and used for astronomy. This paper discusses the design of HTS filters, the mounting of the filters into a cooled receiver and the improved results obtained in astronomical observations. In addition, such a filter has been designed to operate in each element in a focal plane array, in this case a large number of filters are required in the array and miniaturization is a crucial criteria