A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique
In low intermediate frequency (low-IF) receivers, image interference rejection is one of the core tasks to be accomplished. Conventional active polyphase filters (APPFs) are unable to have a sufficient image rejection ratio (IRR) at high operating frequencies due to the degradation of the IRR by the...
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MDPI AG
2025-01-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/16/1/65 |
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| author | Yue Yin Haobo Qi Haodong Lu Ziting Feng Jiayu He Xinbing Zhang Lei Li Xiaofei Qi Xiyuan Feng |
| author_facet | Yue Yin Haobo Qi Haodong Lu Ziting Feng Jiayu He Xinbing Zhang Lei Li Xiaofei Qi Xiyuan Feng |
| author_sort | Yue Yin |
| collection | DOAJ |
| description | In low intermediate frequency (low-IF) receivers, image interference rejection is one of the core tasks to be accomplished. Conventional active polyphase filters (APPFs) are unable to have a sufficient image rejection ratio (IRR) at high operating frequencies due to the degradation of the IRR by the amplitude and phase imbalances produced by the secondary pole. The proposed solution to the above problem is a frequency-dependent image rejection enhancement technique based on secondary pole compensation. By adjusting the dominant pole frequency of the high-pass filter (HPF) appropriately, the proposed technique can theoretically completely reject the image interference signal even in the presence of the secondary pole. The proposed APPF is simulated and fabricated in a 180-nm CMOS process. The simulation results show that the proposed technique can improve the IRR of the APPF by more than 30 dB at the operating frequency of hundreds of MHz. The measured IRR is better than −31 dB at the frequency from 95 to 105 MHz. Unlike conventional schemes, the proposed design is from the perspective of frequency correlation, which makes the operating frequency no longer limited by the secondary pole frequency. In addition, the proposed design also has an excellent IRR for quadrature input signals with phase imbalance. |
| format | Article |
| id | doaj-art-8d44871127b7416c93e2e006c27a411f |
| institution | Kabale University |
| issn | 2072-666X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj-art-8d44871127b7416c93e2e006c27a411f2025-01-24T13:42:00ZengMDPI AGMicromachines2072-666X2025-01-011616510.3390/mi16010065A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement TechniqueYue Yin0Haobo Qi1Haodong Lu2Ziting Feng3Jiayu He4Xinbing Zhang5Lei Li6Xiaofei Qi7Xiyuan Feng8School of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaSchool of Information Science and Technology, Northwest University, No. 1 Xuefu Road, Chang’an District, Xi’an 710127, ChinaSchool of Microelectronics, Northwestern Polytechnical University, No. 1 Dongxiang Road, Chang’an District, Xi’an 710129, ChinaIn low intermediate frequency (low-IF) receivers, image interference rejection is one of the core tasks to be accomplished. Conventional active polyphase filters (APPFs) are unable to have a sufficient image rejection ratio (IRR) at high operating frequencies due to the degradation of the IRR by the amplitude and phase imbalances produced by the secondary pole. The proposed solution to the above problem is a frequency-dependent image rejection enhancement technique based on secondary pole compensation. By adjusting the dominant pole frequency of the high-pass filter (HPF) appropriately, the proposed technique can theoretically completely reject the image interference signal even in the presence of the secondary pole. The proposed APPF is simulated and fabricated in a 180-nm CMOS process. The simulation results show that the proposed technique can improve the IRR of the APPF by more than 30 dB at the operating frequency of hundreds of MHz. The measured IRR is better than −31 dB at the frequency from 95 to 105 MHz. Unlike conventional schemes, the proposed design is from the perspective of frequency correlation, which makes the operating frequency no longer limited by the secondary pole frequency. In addition, the proposed design also has an excellent IRR for quadrature input signals with phase imbalance.https://www.mdpi.com/2072-666X/16/1/65polyphase filtercomplex filterimage rejectionlow intermediate frequency receivernotch filterenhancement technique |
| spellingShingle | Yue Yin Haobo Qi Haodong Lu Ziting Feng Jiayu He Xinbing Zhang Lei Li Xiaofei Qi Xiyuan Feng A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique Micromachines polyphase filter complex filter image rejection low intermediate frequency receiver notch filter enhancement technique |
| title | A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique |
| title_full | A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique |
| title_fullStr | A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique |
| title_full_unstemmed | A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique |
| title_short | A Novel Active Polyphase Filter Employing Frequency-Dependent Image Rejection Enhancement Technique |
| title_sort | novel active polyphase filter employing frequency dependent image rejection enhancement technique |
| topic | polyphase filter complex filter image rejection low intermediate frequency receiver notch filter enhancement technique |
| url | https://www.mdpi.com/2072-666X/16/1/65 |
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