Design of Suspended Stripline Combline Filter with Lossy Resonator

This paper presents both lossless and lossy filter synthesis design using a suspended stripline combline structure. With the evolvement in communication system, there is a growth in demand for compact, high-performance filter. A combline filter structure is able to reduce filter dimension. Lossy combline filter is proposed to overcome the conventional way of designing filter that made ideal assumptions and neglected the loss factor due to the finite Q of practical resonator. Incorporating loss into filter design leads to improvement for more accurate filter design parameters in practical realization. Both lossless and lossy four degree Combline filter using suspended stripline transmission has been designed fabricated and tested.