Synthesis of High-Power Harmonic Rejection Waveguide Filters

Waveguide filters for rejection of harmonic power content of high-power transmitters are widely used, and corrugated waveguide or waffle-iron filters are most commonly employed for this application. The method of design described in the literature is based on the use of image parameters, and may be considered a rather complicated non-optimum procedure which may be difficult to control, particularly in regard to pass band VSWR, since empirical adjustments are usually required. The new methods described here are based on synthesis techniques, and give practical results close to the initial specifications. Only filters of the reflective type will be discussed, but occasionally conversion to the absorptive class is feasible.