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

Marzieh Nasri,Davoud Zarifi,Ashraf Uz Zaman

doi:10.1109/access.2020.2968609

Marzieh Nasri, Davoud Zarifi + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.2968609

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Abstract

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.

Highlights

Directional couplers are widely used in different microwave components and networks
This paper presents a wideband groove gap waveguide (GGW) based 3-dB coupler for V-band applications
The discrepancies between the results may be attributed to extra loss due to metal conductivity degradation owing to surface roughness, the fabrication inaccuracies in the computer numerical control (CNC) milling and assembling tolerances

Summary

INTRODUCTION

These components can be implemented based on different kinds of traditional planar technologies as microstrip lines [1], striplines [2] and substrate integrated waveguides (SIWs) [3] In all of these substrate based structures, low power handling capacity, high substrate and ohmic losses and undesired radiations may be of concern especially for millimeter-wave frequencies. Some synthesis techniques based on equivalent circuit representations have been presented for design of branch-guide directional couplers [6]–[8]. Gap waveguide technology is one of the new suitable guiding structures for millimeter-wave applications [11] This technology offers low-cost and high-performance contactless H-plane waveguide split-block solution where joint between the adjacent metal plates is not an issue. The design is performed in a waveguide branch-guide coupler by using five rectangular apertures in the common wall of two parallel GW guiding structures

GGW STRUCTURE

FABRICATION AND MEASUREMENT

CONCLUSION