Design of a novel structure SIW filter

A microwave substrate integrated waveguide (SIW) filter with compact and novel configuration is presented. The SIW filter will be used for the integration with a frequency multiplier. The overall size of the filter is 60mm length and 40mm width and can just enough meet to the need of frequency multiplier. Measured results show that the stopband rejection of filter is more than 45dB, the insertion loss is less than -1dB at the passband of 7.1-8GHz. Using small-angle lateral coupling, the new structure keeps a sharp transition characteristic at the lower sideband just like the traditional waveguide filter and the characteristic have improved at the upper sideband.