Compact stub resonators with enhanced Q-factor using negative order resonance modes of non-uniform CRLH transmission lines

Shinichi Tanaka, Kyosuke Mukaida, Kei Takata

Research output: Contribution to journalArticle

7 Citations (Scopus)


A compact composite right/left-handed transmission-line (CRLH TL) stub resonator is presented. The bandpass frequency of the resonator and the adjacent transmission-zeros are determined by the negative order resonance modes of the stub line. We demonstrate that these resonance frequencies can be arbitrarily controlled by using non-identical, unbalanced unit cells, leading to enhanced loaded-Q as well as unloaded-Q. We show that despite the presence of lumped element loss the unloaded-Q is enhanced by a factor of 2 compared to that of microstrip line as a result of nearly-zero group velocity. As a consequence, the loaded-Q can be increased without incurring significant insertion loss as in the case of conventional stub resonators on the same substrate. The physical mechanisms of the distinct features are discussed based on an equivalent dispersion diagram, a concept introduced to model general one-port CRLH TL used as a stub line.

Original languageEnglish
Pages (from-to)252-259
Number of pages8
JournalIEICE Transactions on Electronics
Issue number3
Publication statusPublished - 2015 Mar 1



  • CRLH
  • Dispersion diagram
  • Group velocity
  • Metamaterials
  • Q-factor
  • Resonator

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

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