IMPROVED WAVEGUIDE FOR USE IN DUAL POLARISATION PROBE SYSTEM

摘要

A waveguide for use with a dual polarisation waveguide probe system is described which provides an improved frequency response across a desired frequency range (10.7 to 12.75 GHz) and particularly at the band edges. This is achieved by providing a waveguide (14) with a rotator which incorporates a reflecting plate (30) in combination with a differential phase shift portion (36, 38) in the form of a waveguide of slightly asymmetrical cross section so that orthogonal signals which travel through this portion have a different cut-off wavelength. This results in a rotator which achieves 180 DEG of phase shift between two orthogonal components across the frequency range of signals received by the waveguide. The reflecting plate and the differential phase shift portion have inverse frequency characteristics so that the combined phase shift charteristic of the rotator has a flatter frequency characteristic.