Analysis and design of weak coupling coupler based on the half mode substrate integrated waveguide

• Published in: International journal of microwave and wireless technologies Vol. 15; no. 5; pp. 734 - 741
• Main Authors: You, Minghui, Liu, Guohua, Cheng, Zhiqun
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.06.2023
• Subjects: Broadband; Couplers; Coupling; Design; Designers; Directivity; Electric fields; Passive Components and Circuits; Radiation; Substrate integrated waveguides; Transmission lines; Ku-band; Substrate integrated waveguide; Weak coupling coupler; Even-odd mode
• ISSN: 1759-0787; 1759-0795
• DOI: 10.1017/S1759078723000156

Substrate integrated waveguide (SIW) technology represents a good solution for the design of couplers. Coupler structures proposed in most relevant reports cannot achieve excellent performance in the case of weak coupling. This work proposes a new weak coupling coupler architecture, similar to the branch line coupler. The metal via arrays is used to reshape the electric field distribution of the SIW structure, making the overall structure achieve weak coupling characteristics. The even-odd mode decomposition method analyzes this structure's equivalent transmission line model. For this purpose, a systematic design procedure is deployed to achieve several coupling values over a wide frequency bandwidth. A novel half-mode substrate integrated waveguide (HMSIW) coupler with a 29 dB coupling is designed and fabricated for verification based on the proposed method. Good agreements between the calculated and simulated results are observed. The proposed coupler has the advantage of high directivity within the broadband and can be used for SIW-based circuits and power detection in the Ku-band.