Design of miniature wideband interdigital filters
In this paper a practical design procedure is suggested for designing wideband miniature interdigital filters. The proposed design approach is based on a concept of parameter mapping between two wideband filters, i.e. a conventional interdigital filter with uniform impedance resonators (UIR) and a desired miniature interdigital filter using stepped impedance resonators (SIR), allowing filter designers to deploy traditional designs with powerful electromagnetic (EM) simulators. For demonstration, a five-pole SIR interdigital filter with a fractional bandwidth (FBW) of 25% has been designed, fabricated, and tested. The demonstrator shows an excellent performance, which matches well to that of its conventional counterpart so as to validate the proposed design procedure. (C) 2006 Wiley Periodicals, Inc.
interdigital uniform impedance resonators stepped impedance resonators wideband bandpass filters symmetrical interdigital