Three-layer dielectric waveguide with microstrip transition

A three-layer dielectric waveguide is and its transition to microstrip line is proposed and investigated. The proposed waveguide consists of three layer, high dielectric constant layer at the top layer, low dielectric constant at the middle layer, and ground plane at the bottom layer. A simple and compact microstrip transition is proposed and integrated for measurement purpose. A 20mm long section of the proposed waveguide with two microstrip transitions were designed and tested. In the measurement, the total insertion loss is around 3.3dB. The total insertion loss of the proposed waveguide and two transitions is around 1.8dB, while the loss of the two sections of the microstrip line and the test fixture is around 1.5dB.