High Order Harmonic Pass Band Suppression in Microstrip Filter

Abstract

It is very well understood that filters are backbone of communication system as they are employed in each stage of system design and the key parameters which indicates their performance and suitability to desired application are insertion loss, return loss, group delay etc. Apart from them a very important factor namely high order harmonic pass band which becomes very critical when input of the filter consists of multiple harmonic signal within it and creates interference to succeeding stages of the system. In order to achieve clean frequency spectrum in stop band frequency region, there is need of suppressing the high order harmonic spurious pass bands. In this research work additional microstrip patterns are formed at input/output of the filter schematic to achieve the required goal. In this article concept of the novel technique to eliminate or suppress the high order harmonics is detailed and same is implemented on hairpin type of filter topology.