C-Band Combline Bandpass Filter with Enhanced Selectivity: Implementation and Analysis of Complex Coupling Schemes
Nikita A. Shkunov1, Nikita M. Gerasimov1, Boris M. Kats1, Kirill A. Sayapin1,2; 1Waveguide-based Systems LLC, Dmitrov, Russia; 2Saratov State University, Saratov, Russia
Abstract
This work addresses the critical challenge of designing highly selective bandpass filters for C-band systems. It focuses on the synthesis and investigation of a combline filter employing an innovative approach to establishing cross-coupling between resonators. The primary objective is to overcome inherent limitations in roll-off steepness and out-of-band rejection characteristic of conventional topologies. To achieve this, auxiliary resonators, specially configured to enable controlled interactions between non-adjacent main resonators, are integrated into the filter structure, distinguishing the proposed solution from standard designs.
Particular emphasis is placed on justifying the configuration selection and electromagnetic parameters of these auxiliary resonators, which are responsible for implementing the target cross-coupling scheme. The design methodology is comprehensively described, encompassing an initial analytical synthesis stage followed by rigorous geometry optimization utilizing state-of-the-art 3D full-wave electromagnetic simulation techniques. Simulated results—specifically the frequency-dependent S-parameters are presented and analyzed, demonstrating close adherence to target specifications. Key achieved performance metrics include a center frequency of 3.76 GHz, a -3 dB bandwidth of 270 MHz, minimal in-band insertion loss, high stopband rejection levels, and the requisite passband shape.
The obtained results convincingly demonstrate the high efficacy of the proposed methodology. Utilizing specially configured resonator structures to implement complex cross-coupling in combline filters presents significant potential for developing compact devices with enhanced functionality—notably improved selectivity and tailored frequency response characteristics. This approach holds considerable promise for advanced telecommunications and radar systems.
Speaker
Shkunov Nikita aleksandrovich
Waveguide-based Systems LLC, Dmitrov, Russia
Russia
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