volume | PIER Journals

2025-12-27

Compact and Broadband CPW-to-RWG Transition Using 180° Phase Shifter

Yueh-Hsien Cheng,

Dr. Yueh-Hsien Cheng

National Taiwan University of Science and Technology

Taiwan

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Chun-Long Wang

Prof. Chun-Long Wang

Department of Electronic and Computer Engineering

National Taiwan University of Science and Technology

Taiwan

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Progress In Electromagnetics Research C, Vol. 164, 51-57, 2026

doi:10.2528/PIERC25092403 | Google Scholar

Abstract

In this paper, a compact and broadband 50-Ω coplanar waveguide-to-rectangular waveguide (CPW-to-RWG) transition using a 180° phase shifter and a meandered dipole is proposed. The frequency range, for which the reflection coefficient is smaller than -15 dB, covers the whole X-band (8.2~12.4 GHz). In addition to the broadband performance, the transition occupies a small length of 7.37 mm. Furthermore, the characteristic impedance of the coplanar waveguide is 50 Ω, which conforms to the commonly used 50 Ω impedance of radio frequency systems. To further reduce the circuit size, a compact and broadband 50-Ω CPW-to-RWG transition using an inductance-compensated 180° phase shifter and a meandered dipole is proposed. The frequency range, for which the reflection coefficient is smaller than -15 dB, also covers the whole X-band (8.2~12.4 GHz). Besides, the transition size is reduced from 7.37 mm to 6.55 mm, which is smaller than a quarter-wavelength. Furthermore, the characteristic impedance of the coplanar waveguide is of the nominal value of 50 Ω.

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Yueh-Hsien Cheng, and Chun-Long Wang, "Compact and Broadband CPW-to-RWG Transition Using 180° Phase Shifter," Progress In Electromagnetics Research C, Vol. 164, 51-57, 2026.
doi:10.2528/PIERC25092403

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