Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band
Recently, the spurious self-suppression method has been introduced and applied to the bandpass TM cavity filters to improve their stopband performance. However, this method has the limitation of being applicable only to TM narrow-band filters. This paper shows how to overcome this limitation. In par...
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| Format: | Article |
| Language: | English |
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IEEE
2023-01-01
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| Series: | IEEE Access |
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| Online Access: | https://ieeexplore.ieee.org/document/10132474/ |
| _version_ | 1797810676511539200 |
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| author | Abdul Rehman Cristiano Tomassoni |
| author_facet | Abdul Rehman Cristiano Tomassoni |
| author_sort | Abdul Rehman |
| collection | DOAJ |
| description | Recently, the spurious self-suppression method has been introduced and applied to the bandpass TM cavity filters to improve their stopband performance. However, this method has the limitation of being applicable only to TM narrow-band filters. This paper shows how to overcome this limitation. In particular, it shows how to increase the bandwidth and improve the stopband performance by removing the spurious resonance of the coupling irises due to TE<sub>10</sub> mode. The conventional rectangular iris is replaced by a new bent c-shaped iris. In this way, the resonance of the iris TE<sub>10</sub> mode can be shifted to lower frequencies (below the cut-off), improving the stopband performance of the filter. Moreover, this new iris shape provides large couplings that allow wide passbands, and strong excitation of the spurious resonant modes that allows for an efficient implementation of the spurious self-suppression method. Furthermore, double slot iris has been used to connect the two central cavities to increase the central coupling of the filter. Design examples of 4<sup>th</sup> order and 6<sup>th</sup> order TM cavity filters with wide spurious free range up to 18 GHz having fractional bandwidth (FBW) of 5% and 4%, respectively, are presented. Finally, the 6<sup>th</sup> order TM cavity filter has been manufactured and measured. Good agreement has been achieved between simulated and measured frequency responses. |
| first_indexed | 2024-03-13T07:12:27Z |
| format | Article |
| id | doaj.art-f597a29e06a84544a218795097d0714c |
| institution | Directory Open Access Journal |
| issn | 2169-3536 |
| language | English |
| last_indexed | 2024-03-13T07:12:27Z |
| publishDate | 2023-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Access |
| spelling | doaj.art-f597a29e06a84544a218795097d0714c2023-06-05T23:00:27ZengIEEEIEEE Access2169-35362023-01-0111528775288510.1109/ACCESS.2023.327972110132474Wideband Bandpass TM Cavity Filters With Wide Spurious Free BandAbdul Rehman0https://orcid.org/0000-0003-1070-1583Cristiano Tomassoni1https://orcid.org/0000-0001-7933-7121Electronic and Information Engineering Department, University of Perugia, Perugia, ItalyElectronic and Information Engineering Department, University of Perugia, Perugia, ItalyRecently, the spurious self-suppression method has been introduced and applied to the bandpass TM cavity filters to improve their stopband performance. However, this method has the limitation of being applicable only to TM narrow-band filters. This paper shows how to overcome this limitation. In particular, it shows how to increase the bandwidth and improve the stopband performance by removing the spurious resonance of the coupling irises due to TE<sub>10</sub> mode. The conventional rectangular iris is replaced by a new bent c-shaped iris. In this way, the resonance of the iris TE<sub>10</sub> mode can be shifted to lower frequencies (below the cut-off), improving the stopband performance of the filter. Moreover, this new iris shape provides large couplings that allow wide passbands, and strong excitation of the spurious resonant modes that allows for an efficient implementation of the spurious self-suppression method. Furthermore, double slot iris has been used to connect the two central cavities to increase the central coupling of the filter. Design examples of 4<sup>th</sup> order and 6<sup>th</sup> order TM cavity filters with wide spurious free range up to 18 GHz having fractional bandwidth (FBW) of 5% and 4%, respectively, are presented. Finally, the 6<sup>th</sup> order TM cavity filter has been manufactured and measured. Good agreement has been achieved between simulated and measured frequency responses.https://ieeexplore.ieee.org/document/10132474/Bandpass filtersbent c-shaped iriscoupling iriseshigher order modesout-of-bandspurious self-suppression |
| spellingShingle | Abdul Rehman Cristiano Tomassoni Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band IEEE Access Bandpass filters bent c-shaped iris coupling irises higher order modes out-of-band spurious self-suppression |
| title | Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band |
| title_full | Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band |
| title_fullStr | Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band |
| title_full_unstemmed | Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band |
| title_short | Wideband Bandpass TM Cavity Filters With Wide Spurious Free Band |
| title_sort | wideband bandpass tm cavity filters with wide spurious free band |
| topic | Bandpass filters bent c-shaped iris coupling irises higher order modes out-of-band spurious self-suppression |
| url | https://ieeexplore.ieee.org/document/10132474/ |
| work_keys_str_mv | AT abdulrehman widebandbandpasstmcavityfilterswithwidespuriousfreeband AT cristianotomassoni widebandbandpasstmcavityfilterswithwidespuriousfreeband |