Title :
An ultra-narrowband HTS bandpass filter
Author :
Dustakar, K. ; Berkowitz, S.
Author_Institution :
Conductus Inc., Sunnyvale, CA, USA
Abstract :
This paper presents the measured results of an HTS ultra-narrowband bandpass filter with a 100 kHz bandwidth. This filter, with a fractional bandwidth of 0.014% and a center frequency of 700 MHz, represents a previously unrealized portion of filter parameter space. This filter was realized using a five-pole Chebyshev filter design and was fabricated using an HTS microstrip configuration. This filter required very high Q, very weak coupling, and a strong reduction in parasitics. Unloaded Qs of 135,000 were achieved with a resulting insertion loss of 1.37 dB. Even resonator Qs of 20,000 would lead to a filter loss of 9 dB. A noise figure of 1 dB was achieved for a complete system with this filter and a cryogenic low-noise amplifier.
Keywords :
Chebyshev filters; Q-factor; UHF filters; band-pass filters; high-temperature superconductors; microstrip filters; resonator filters; 1 dB; 1.37 dB; 100 kHz; 700 MHz; 9 dB; Q-factor; cryogenic low-noise amplifiers; filter center frequency; filter fractional bandwidth; high-Q HTS frequency-dependent resonators; high-temperature superconductors; insertion loss; microstrip filters; multi-pole Chebyshev filters; parasitics reduction; ultra-narrowband HTS bandpass filters; weak filter coupling; Band pass filters; Bandwidth; Chebyshev approximation; Cryogenics; Frequency; High temperature superconductors; Insertion loss; Microstrip filters; Noise figure; Resonator filters;
Conference_Titel :
Microwave Symposium Digest, 2003 IEEE MTT-S International
Conference_Location :
Philadelphia, PA, USA
Print_ISBN :
0-7803-7695-1
DOI :
10.1109/MWSYM.2003.1210524
