Title :
Superconducting microstrip bandpass filter on LaAlO3 with high out-of-band rejection
Author :
Reppel, Michael ; Mage, Jean-Claude
Author_Institution :
Wuppertal Univ., Germany
fDate :
5/1/2000 12:00:00 AM
Abstract :
A superconducting eight-pole narrow-band filter on lanthanum aluminate substrate material (εr≈4) is introduced. The filter has a center frequency of 1.8 GHz and a fractional bandwidth of 0.84%. Steep filter skirts (~20 dB at 700 kHz) and high out-of-band rejection (~60 dB at 5 MHz) have been achieved by a quasi-elliptic filter design with two transmission zero pairs. The measured high-quality factor of ~60 000 at 70 K results in an insertion loss of less than ~0.3 dB in the passband and ~0.5 dB at the band edges
Keywords :
Q-factor; band-pass filters; barium compounds; elliptic filters; high-temperature superconductors; microstrip filters; poles and zeros; superconducting microwave devices; yttrium compounds; 1.8 GHz; 5 MHz; 70 K; 700 kHz; LaAlO3; YBa2Cu3O7-LaAlO3; band edges; center frequency; fractional bandwidth; high-quality factor; insertion loss; out-of-band rejection; quasi-elliptic filter design; steep filter skirts; superconducting microstrip bandpass filter; transmission zero pairs; Band pass filters; Bandwidth; Filtering theory; Frequency; Lanthanum; Loss measurement; Microstrip filters; Narrowband; Superconducting filters; Superconducting materials;
Journal_Title :
Microwave and Guided Wave Letters, IEEE
