Wideband forward-wave 3-dB coupler constructed by coupled lines and via-wall structures

Abstract

This paper presents wideband forward-wave coupled-line couplers loaded with metallic via walls. The proposed coupler features wide bandwidth. The two via walls enable good impedance matching of even and odd modes. Moreover, the proposed structure can remain stable phase difference over a wide frequency range, yielding wide bandwidth. The -1 dB bandwidth of the 3-dB coupler is 45% (6.8-10.75 GHz). Compared with the traditional coupled-line coupler, the proposed coupler achieves wide bandwidth.