A novel design approach for microwave planar filters

Very Compact Spiral Resonator Implementation of Narrow-band Superconducting Quasi-Elliptic Filters

“…Although "space mapping" [11] has not been explicitly formalized here, the procedure does contain a "coarse model" (graphs of k and ke versus g, andfo versus spiral size) which is fine-tuned by a "fine model" (parameters extracted by fitting a curve to a simulation of the whole filter). The revised graphs not only include a correction for the coarse mesh size that was used initially but also show the apparent values of k, ke or fo resulting from ignoring most cross-couplings, thereby indirectly correcting for cross-coupling (and anything else present in the fine model but not the coarse model).…”

Distributed Models for Filter Synthesis

“…As a result, the prototype response is a rational function in terms of a common complex frequency variable s. These approximations are valid for narrowband applications, where a constant coupling matrix completely defines the prototype and the real filter behavior [5]. Exploiting the coupling matrix or equivalent schemes, very powerful synthesis and design methods of narrowband filters have been developed (see [12], [13], [15], [47] and [48] to cite a few). However, as the filter bandwidth increases, the accuracy of the previous methods is seriously reduced.…”

“…This classic procedure consists of the three following steps: first, starting from wellknown mathematical models, an equivalent circuit prototype (either based on lumped and/or distributed elements) is synthesized [11]; second, after identifying the prototype elements with real structure parts, initial estimates for the physical dimensions are obtained [12], [13]; and third, a final optimization of the filter dimensions is typically performed [14]- [16]. The success of this design procedure is based on the similarities between the equivalent circuit prototype and the real filter structure.…”

Development of CAD models for space engineering

“…The first example concerns a parameter extraction approach developed for the design of microwave filters [14][15][16]. The design of microwave filters is particularly difficult in space engineering where the demand for narrow-band band-pass filter is important.…”