Design of a multi-section coupled line coupler based on substrate integrated coaxial lines

摘要

In this paper, a novel multi-section coupled line substrate integrated coaxial line (SICL) coupler design is presented. The proposed SICL coupler features high directivity when compared to microstrip designs as it supports TEM propagation mode and inherits the merits of coaxial lines. The use of multiple sections enhances the bandwidth due to the longer electrical length. The work covered includes a comparison of characteristics of the proposed SICL multi-section coupler with its microstrip and stripline counterparts. Comparison also includes characteristics of microstrip, stripline, and SICL single section couplers for completeness. Moreover, the comparisons show that the proposed SICL coupler improves the characteristics without increasing the physical footprint. However, comparison did not show any significant improvement in directivity and bandwidth over the equivalent stripline designs.