High-Pass Directional Couplers using a Simple Linear Coupling Function

Wideband directional couplers are among the microwave components extensively used in electronic warfare, electronic countermeasures, and instrumentation. In this paper, a simple straight line coupling function is used to design a high-pass directional coupler. The ripple performance of a coupler using the linear coupling function is shown to be superior to couplers designed using the cosine type coupling function as reported in (5). In addition, the straight line coupling function is easier to visualize and implement in the design of directional couplers. Other coupling functions such as the Cos type (6) coupling variation provide further reductions in ripple level, but with added mathematical and process complexities.