Double‐layer suspended stripline resonator with high quality factor for base‐station diplexer application

Abstract

A novel double-layer suspended stripline (DSSL) resonator with high unloaded quality factor is proposed. The DSSL resonator consists of a thin substrate with metal strips on both sides connected by a metallic via hole suspended in the centre of an air-filled cavity, which leads to a much higher unloaded quality factor than the conventional single-layer suspended stripline resonator with an identical resonant frequency. The resonance characteristics of the DSSL resonator are parametric analysed. For demonstration, a compact diplexer for basestation application with channel centre frequencies at 1.95 and 2.14 GHz and absolute bandwidths of 60 MHz is designed, fabricated and measured. The synthesised, simulated and measured results show a good agreement.

Design of pseudoelliptic filters with controllable transmission zeros using high‐ Q double‐layer suspended stripline resonators

“…There is an innovative structure proposed in our former work that has been proved to be very efficient in enhancing the Q u . The basic element is a double‐layer suspended stripline (DSSL) resonator shown in Figure B, which is composed of metallic strips on both sides connected by a metallic via compared with the conventional single‐layer SSL form shown in Figure A.…”

“…Therefore, dielectric loss is lower thereby achieving a much higher Q u . Unfortunately, no detailed design techniques, or systemic design procedures are mentioned in Reference , e.g., how to determine the dimensions of the physical structure to achieve the desired external coupling and inter‐resonator coupling coefficients, and to determine the operating frequency, bandwidth and the location of TZs. It is extremely difficult for a designer to effectively exploit the innovative structure.…”