Design of a Variable Directional Coupler in Rectangular Waveguide

Abstract

A design theory of a three-aperture rectangular waveguide coupler with adjustable directivity and coupling factor achieved by introducing a very thin slice of an anisotropically conducting material like Pyrolytic Graphite (P.G.) in the central aperture is discussed. By suitable adjustment of the orientation angle of the anisotropically conducting aperture, the directivity can be maintained at very high value over a bandwidth given by 0.5 ⩽ λλ_go/λ_g ⩽ 1.5. The corresponding variation of coupling factor withλλ_go/λ_g has been presented and variation of coupling factor and directivity with orientation angle at the design frequency has been studied.

Indexing Terms:

• Directional Coupler
• Waveguide
• Directivity
• Coupling Factor