Electromagnetically coupled microstrip square/circular ring resonators: Inset/offset feed variation effects on resonance frequency

Abstract

Inset/offset feed‐dependent variation of electromagnetically coupled microstrip square and circular ring resonators (MSRR/MCRR) over a wide range indicate overall increase and decrease in resonant frequency (fr) respectively. On the basis of the experimental results, equations are suggested to determine fr as a function of the normalized inset and offset feed positions. Equations are validated for a limited range. High values of quality factor Q = 618 are obtained with MSRR as compared with MCRR (Q = 375) at two offset points near the ring edge with VSWR ≈ 1. This advantage can be used for applications such as frequency‐selective circuits and sensors. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2118–2121, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22696

New perturbation technique to generate split modes in electromagnetically coupled notch filters using different ring resonators

“…Ghanbari et al [7,8] have reported somewhat similar experimental work (on CRR with EM coupled feed line variation), but only by reflection measurements and their EM coupled feed line terminating inside the ring only. They could not get any splitting (which we have confirmed by simulation for their geometry).…”

“…All the rings were designed for nominally the same frequency of 2.4 GHz for only the ring on a substrate, without considering actual situation of EM coupling geometry, for comparison with the previous reports [7][8][9][10]. This is, however, not very critical in present work, as our main interest is the relative changes, using this as reference, for triangular and square rings chamfering is used at all the corners.…”

“…However the applications were different i.e. (i) patch and ring antennas, where no splitting is reported with variation of offset as well as inset or (ii) circular ring resonator with positional overlays [7,8]. This latter experimentation gave split modes but with positional overlay -angle variation, which was fitted to very complex equation than in [5,6] and no feed line offset variation was done (offset was fixed zero).…”