Flat-group-delay RF planar filters with transmission zeros using transversal circuits
Various families of flat-in-band-group-delay RF planar bandpass filters (BPFs) with multiple out-of-band transmission zeros (TZs) in their filtering transfer function are presented. As the first approach, a type of BPFs with theoretically-constant group-delay profile and perfect two-port-reflectionl...
| Autores: | , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Recursos: | Universidad de Alcalá (UAH) |
| Repositorio: | e_Buah Biblioteca Digital Universidad de Alcalá |
| Idioma: | inglés |
| OAI Identifier: | oai:ebuah.uah.es:10017/65190 |
| Acesso em linha: | http://hdl.handle.net/10017/65190 https://dx.doi.org/10.1109/TCSI.2023.3298219 |
| Access Level: | acceso abierto |
| Palavra-chave: | Absorptive filter Analog filter Bandpass filter (BPF) Bessel filter Directional coupler Discrete-time-filter modeling Group delay Hybrid ring Microstrip filter Microwave filter Planar filter Reflectionless filter Reflective filter RF filter Transmission zero (TZ) Transversal filter Telecomunicaciones Telecommunication |
| Resumo: | Various families of flat-in-band-group-delay RF planar bandpass filters (BPFs) with multiple out-of-band transmission zeros (TZs) in their filtering transfer function are presented. As the first approach, a type of BPFs with theoretically-constant group-delay profile and perfect two-port-reflectionless behavior is proposed. The theoretical sufficient conditions to obtain a frequency-constant group delay in a generalized form of transfer function for these BPFs are derived. They are then particularized in transmission-line-based transversal-circuit realizations with flat-in-band-group-delay and quasi-reflectionless characteristics. Afterwards, a class of reflective-type BPFs based on directional power couplers that are arranged in transversal-mode topologies are addressed toward its practical demonstration for the first time. These BPFs, which exhibit flat in-band group delay, are compared with their classic Bessel-type BPF counterparts without TZs. Moreover, discrete-time models of such BPFs are derived, analyzed, and discussed. For experimental-validation purposes, proof-of-concept microstrip prototypes centered at 2.5-GHz of the engineered quasi-absorptive/reflective-type flat-in-band-group-delay BPFs are designed, manufactured, and characterized. |
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