HTSC microstrip UHF filter at 2 GHz

Abstract

HTSC planar high Q resonators can be used to realize microstrip filters. These filters have a low insertion loss and a sharp slope. The size of the substrates of 10 mm x 10 mm leads to a low frequency limit of about 2 GHz for a two-pole filter. At 77 K the measured on-chip insertion loss of a two-pole Butterworth bandpass filter with 3% relative bandwidth is less than 0.2 dB. The complete filter including housing and coaxial connectors has an insertion loss of 0.4 dB. Improving the structuring process and reoptimizing the filter design will improve the filter characteristic. Particularly low-loss bonded contacts instead of silver paint between the coaxial microstrip transition will decrease the insertion loss of the filter. Outer dimensions of the filter housing with coaxial connectors are 34 mm x 30 mm x 20 mm. Waveguide filters with comparable filter characteristics will be approximately 100 times larger in volume than planar HTscfilters and they are useless for a olanar system with active and oassive components on a single board.

Resonator structure with high etching error tolerance for application in HTS filters

“…Introducing lump element capacitance can further reduce size. Ring resonators, Meander-line resonators [7,8] and spiral resonators [9][10][11][12] are also self-coupled resonators with a more complicated structure and internal couplings. Figure 2 shows the layout of a closed loop self-coupled resonator.…”

High-temperature superconducting dual-spiral resonators and their application in filter miniaturization

“…Meander-line resonators are another type of miniature resonators and they can be taken as the modifications of conventional straight ribbon (λ/2) resonators by folding the microstrip ribbons several times [8]. A two-stage bandpass filter at 2 GHz has been designed and fabricated using meander-line resonators [9]. In the filter, interdigital capacitors are used to provide the couplings between the meander-line resonators and the input/output ports.…”

Influence of forbidden transitions on the gain-band structure of XeCl molecules

“…A two-stage bandpass filter at 2 GHz has been designed and fabricated using meander-line resonators [9]. In the filter, interdigital capacitors are used to provide the couplings between the meander-line resonators and the input/output ports.…”