Design and fabrication of a 6db compact directional coupler

Abstract

In this paper, we will present a planar geometry design for a 6dB compact microwave coupler, and will further explore and discuss the results of an electromagnetic simulation in Sonnet® Suites™ Electromagnetic simulation software. Being a compact coupler, the device features a minute circuit footprint size, while still observing the limitations of the production technologies involved in manufacturing it. The technology utilized in the paper is a 4 port microstrip copper trace on a production-friendly and extremely economical FR4 dielectric substrate. The circuit shows excellent performance in a 1.8GHz bandwidth (3.9GHz – 5.7GHz), with a loss of 6dB on the coupled port. A further advantage of this geometry is a very linear and predictable change in the S-parameter values as a result of small linear changes in the geometry