Open AccessMiniaturised quadrature hybrid coupler using composite planar transmission lines
Author(s) -
Tian Haiyan,
Chung Kwok L.,
Liu Ruiqi,
Dai Mingfu,
Tang Wenzhong
Publication year - 2019
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2019.1704
Subject(s) - microstrip , hybrid coupler , planar , return loss , rat race coupler , insertion loss , coplanar waveguide , quadrature (astronomy) , electric power transmission , materials science , transmission line , footprint , power dividers and directional couplers , magic tee , electronic engineering , optics , optoelectronics , computer science , microwave , electrical engineering , physics , engineering , telecommunications , paleontology , computer graphics (images) , antenna (radio) , biology
In this Letter, a novel miniaturisation technique for a 3‐dB quadrature hybrid coupler is described. The revolutionary structure is composed of folded microstrip lines and folded coplanar waveguides that are printed on the top‐ and bottom‐surfaces of a dielectric substrate, respectively. The two different planar lines are connected by copper vias to form the double‐path composite microstrip‐coplanar waveguide (CMCPW) line. To demonstrate the effectiveness of the technique, a simple yet miniaturised hybrid coupler is devised by introducing folded S‐shaped CMCPW‐lines, wherein their lengths are gradually changed to address the design goals. The simulated and measured results of the proposed coupler validate its good performance metrics in the amplitude responses of power splitting, return‐ and insertion‐loss. Moreover, its isolation and quadrature phase between outputs have been examined. A very small footprint size of 0.0667 λ 0 × 0.0667 λ 0 at 0.5 GHz has been realised.