Tri‐band superconducting filter based on crossed resonators with controllable coupling and feeding structures

Abstract

In this article, a compact tri-band high-temperature superconducting filter with controllable coupling and feeding structures based on crossed resonator which consists of two-end-open UIR with a short stub and an open stub shunted at the resonator center is proposed. Due to the symmetrical structure of the proposed resonator, the odd-and even-mode analysis method can be used to derive their resonance frequencies. Then, a capacitance-loaded microstrip line is added between the resonators to flexibly control the bandwidths. Furthermore, one tapped line and one coupled line are utilized to realize the acquired external coupling under prior specifications. For demonstration, a tri-band filter operating at 1.6 GHz (Global Positioning System), 2.45 GHz (Wireless Local Area Networks), and 3.5 GHz (WiMAX) is designed, analyzed using the electromagnetic simulator, and fabricated using an YBa 2 Cu 3 O y thin film on an MgO substrate. The measured results agree well with the simulated ones.

Miniaturized Quadband High-Temperature Superconducting Bandpass Filter with a Wide Frequency Ratio

“…Owing to the advances in high-temperature superconducting (HTS) materials and processing technology (in terms of stability), HTS microstrip filters and their design have gained significance. Recently, BPFs with multiple passbands have been extensively studied [3][4][5][6][7][8][9][10][11]. A miniaturized quint-band HTS BPF was developed based on a multimode resonator with a single perturbation [3].…”

“…A steppedimpedance stub-loaded stepped-impedance resonator (SIR) was proposed to design a dual-band BPF [4]. A compacted tri-band HTS BPF with controllable feeding/coupling structures based on crossed resonators was developed [5]. A stepped-impedance stub-loaded interdigital capacitor resonator for designing a dual-band BPF with a large bandwidth ratio was also developed [6].…”

“…A stepped-impedance stub-loaded interdigital capacitor resonator for designing a dual-band BPF with a large bandwidth ratio was also developed [6]. As mentioned, all the multiband filters in References [3][4][5][6] were implemented using HTS-based technologies. These studies have summarized the advantages and limitations of HTS BPFs using two modes and bands [7].…”