A High-Temperature Superconducting Notch Filter to Suppress Cellular-Band Interference in Radiotelescopes

An experimental high-temperature superconducting four-pole filter for mitigation of the IMT 2000 cellular band in radiotelescopes is presented. The filter uses a novel capacitive cross-coupling to achieve a quasi-elliptic response. Composite right/left-handed (CRLH) zeroth-order resonators are used to avoid harmonic generation throughout the UHF and L-bands.