PROJECT TITLE :

Synthesis scheme for wideband filters consisting of three-coupled-lines including the cross-coupling between non-adjacent lines

ABSTRACT:

To accurately style wideband filters composed of three-coupled-lines, an improved equivalent circuit is derived by taking the cross-coupling between non-adjacent lines into consideration. Since the cross-coupling between non-adjacent lines is additionally smitten by the coupling between adjacent lines, conventional synthesis techniques cannot be used directly. Instead, an improved synthesis scheme based on successive iterations is proposed to synthesise the filters. As examples, two two-stage microstrip 3-coupled-line filters [bandwidth: a pair of.67–5.thirty three GHz (fractional bandwidth: 67percent)] with a reversed connection sequence are synthesised, simulated, and experimentally realised to validate the proposed theory. The frequency responses of the designed filters using the authors’ new model and synthesis theory compare well with those by simulation and experiment, whereas a mistake of regarding seventeen% is found in bandwidth if the authors use the traditional model that neglecting the cross-coupling between non-adjacent lines. Further, the asymmetric property of the 3-line unit is revealed.