A Wideband 3-dB Directional Coupler in GGW for Use in V-Band Communication Systems

In this article, a broadband 3-dB directional coupler is proposed using groove gap waveguide (GGW) structures. Gap waveguide technology has been introduced to overcome manufacturing and assembling challenges of different millimeter-wave components and devices. The presented coupler has wideband coupling flatness with low return loss in 60-GHz frequency band and can be easily adapted to other frequency ranges. Experimentally, a sample prototype of the proposed 3-dB coupler has been designed and fabricated. The measured return loss and isolation are better than 20 dB and the power-split unbalance within ±0.5 dB is obtained over the frequency range from 57 to 74 GHz (26% BW). The proposed structure has the capability of easily integrating with other millimeter-wave components.