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Transitional combline/evanescent-mode microwave filters
- Source :
- IEEE Transactions on Microwave Theory and Techniques. Dec, 1997, Vol. 45 Issue 12, p2094, 6 p.
- Publication Year :
- 1997
-
Abstract
- Traditional combline-filter theory based on TEM-mode coupling results in bandwidths which are too large - the increase being a function of the ground-plane spacing to wavelength ratio b/[Lambda]. As the b/[Lambda] ratio increases from 0.05 to 0.35, the bandwidth ratio (BWR), defined as actual bandwidth/TEM bandwidth, increases from unity to over 2:1. This bandwidth increase has now been confirmed by calculation of the coupling coefficient between combline resonators using mode matching. Accompanying the increased bandwidth is a considerable increase in the unloaded Q in accordance with the higher Q of the evanescent waveguide modes. A similar study carried out in the case of interdigital filters shows that these effects are much less significant. Index Terms - Bandpass filters, coaxial filters, combline filters, microwave filters, mode matching.
Details
- ISSN :
- 00189480
- Volume :
- 45
- Issue :
- 12
- Database :
- Gale General OneFile
- Journal :
- IEEE Transactions on Microwave Theory and Techniques
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.20757926