A Compact Wideband Crossover Coupler with Lumped Elements

• Main Authors: Kwangwon Park, Hyunkyu Lee, Iljin Lee, In-Woong Kang, Sanggeun Jeon
• Format: Article
• Language: English
• Published: The Korean Institute of Electromagnetic Engineering and Science 2019-04-01
• Series: Journal of the Korean Institute of Electromagnetic Engineering and Science
• Subjects: Butler Matrix; Crossover Coupler; Lumped Elements; Planar Circuits
• Online Access: http://www.jees.kr/upload/pdf/jees-2019-19-2-96.pdf

A compact wideband crossover coupler with fully lumped elements is presented. To achieve a wideband operation, a three-section branch-line structure is employed for the crossover coupler. The size is significantly minimized by replacing transmission lines with lumped elements. The measurement shows that the insertion loss, isolation, and return loss are 1.7 dB, 24 dB, and 14.5 dB, respectively, at 2 GHz. The fractional bandwidth of 20-dB isolation and 3-dB insertion loss is 27%. The size of the crossover coupler is 11 mm × 9 mm, which corresponds to 0.07λ × 0.06λ at 2 GHz. This is significantly smaller than a conventional three-section branch-line crossover coupler by 95%.