Size Reduction and Harmonic Suppression of Rat-Race Hybrid Coupler Using Defected Ground Structure

Y. J. Sung, C. S. Ahn, Young Sik Kim

Research output: Contribution to journalArticle

146 Citations (Scopus)


In this letter, a defected ground structure (DGS) is applied to design a compact microstrip rat-race hybrid coupler. The proposed structure can achieve both a significant reduction of size and harmonic signal. By embedding the DGS section, it is observed that the resonant frequency of the hybrid coupler is significantly lowered, which can lead to a large amount of size reduction for a fixed frequency operation. Besides, the third harmonic signal is suppressed to -30 dB with respect to a conventional rat-race hybrid coupler. In this case, the measured insertion loss is comparable to that of a conventional hybrid coupler.

Original languageEnglish
Pages (from-to)7-9
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number1
Publication statusPublished - 2004 Jan 1



  • Defected ground structure
  • Rat-race coupler

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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