DESIGN OF COMPACT, NARROW-BAND, BAND-PASS MICROWAVE FILTERS IN COPLANAR WAVEGUIDE TECHNOLOGY

摘要

A new topology for designing compact, band-pass filters of arbitrary order is proposed. The basic building block of band-pass filters designed using this technique is a capacitively coupled secondorder filter, which can be thought of as the unit cell of a higher order band-pass filter. The second-order filter is composed of slow-wave transmission line resonators separated by an inductive admittance inverter. To easily control the bandwidth of the filter, the entire structure is capacitively coupled to the feeding transmission lines using series capacitors. This unit cell can be used in different cascading schemes to obtain filters of odd and even orders. Using this technique, band-pass filters with fractional bandwidths in the range of 1-20% can easily be designed. Several different examples of such band-pass filters along with their measurement results are presented and discussed in this article.