Dual-mode filter using ring resonator with non-uniform linewidth

• Published in: Electronics letters Vol. 54; no. 18; pp. 1076 - 1078
• Main Author: Sung, Y
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 06.09.2018
• Subjects: asymmetric structure; band‐pass filters; chip inductor; circular hole; circular patch; degenerate modes; dual‐mode bandpass filter; dual‐mode filter; inductors; meander line; Microwave technology; nonuniform linewidth ring resonator; resonator filters; single ring resonator; skirt characteristics; transmission zero; resonator filters; transmission zero; dual-mode filter; circular hole; dual-mode bandpass filter; asymmetric structure; skirt characteristics; meander line; circular patch; single ring resonator; nonuniform linewidth ring resonator; band-pass filters; inductors; chip inductor; degenerate modes
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2018.5530

A dual-mode bandpass filter is proposed using a single ring resonator with non-uniform linewidth. The proposed filter consists of a circular patch with a circular hole and two chip inductors loaded into the gap in the ring. The non-uniform linewidth ring resonator can be realised by moving a circular hole in the circular patch. This asymmetric structure creates a pair of degenerate modes, and thus acts as a dual-mode filter. Two inductors applied to the gap generate one transmission zero on each side of the passband, improving the skirt characteristics of the filter. In addition, a dual-mode filter with the same characteristics is implemented by replacing the chip inductor with a meander line.