Planar Wideband High-Selectivity Impedance-Transforming Differential Bandpass Filter With Deep Common-Mode Suppression

In this brief, a novel balanced filter named impedance-transforming differential bandpass filter (ITDBPF) is proposed, which is the first differential device to realize both wideband impedance transformation and bandpass filtering simultaneously. A core block consisting of cascaded transmission lines and parallel stubs forms this presented circuit with two additional open stubs. Under differential-mode excitation, the transfer function of the equivalent circuit is the same as the one of Chebyshev, and the filtering characteristics are obtained corresponding to the specified filtering parameters. The open stubs increase multiple transmission zeros under common-mode excitation to greatly broaden the bandwidth of common-mode rejection. To verify the proposed theory, a wideband balanced filter centered at 2 GHz with a theoretical 3-dB bandwidth of 72% is designed and measured to prove the correctness of the design theory.

[1]  Haiwen Liu,et al.  Design of Tri-Band Balanced Filter With Wideband Common-Mode Suppression and Upper Stopband Using Square Ring Loaded Resonator , 2020, IEEE Transactions on Circuits and Systems II: Express Briefs.

[2]  Junfa Mao,et al.  A New Balanced-to-Balanced Power Divider/Combiner , 2012, IEEE Transactions on Microwave Theory and Techniques.

[3]  Feng Huang,et al.  Analysis and Design of a New Self-Packaged Wideband Balun Bandpass Filter With the Functionality of Impedance Transformation , 2019, IEEE Transactions on Microwave Theory and Techniques.

[4]  Yongle Wu,et al.  Broadband Power Amplifier Based on a Generalized Step-Impedance Quasi-Chebyshev Lowpass Matching Approach , 2020, IEEE Transactions on Plasma Science.

[5]  Dimitrios Peroulis,et al.  Multi-Stub-Loaded Differential-Mode Planar Multiband Bandpass Filters , 2018, IEEE Transactions on Circuits and Systems II: Express Briefs.

[6]  Lei Zhu,et al.  Strip-Loaded Slotline Resonator for Compact Differential-Mode Bandpass Filters with Improved Upper Stopband Performance , 2017, IEEE Microwave and Wireless Components Letters.

[7]  M. Ohira,et al.  Synthesis Theory of Ultra-Wideband Bandpass Transformer and its Wilkinson Power Divider Application With Perfect in-Band Reflection/Isolation , 2019, IEEE Transactions on Microwave Theory and Techniques.

[8]  Qing-Xin Chu,et al.  Wideband Balanced Filters With High Selectivity and Common-Mode Suppression , 2015, IEEE Transactions on Microwave Theory and Techniques.

[9]  Fadhel M. Ghannouchi,et al.  Planar Wideband Differential-Mode Bandpass Filter With Common-Mode Noise Absorption , 2017, IEEE Microwave and Wireless Components Letters.

[10]  Yuanan Liu,et al.  High Performance Single-Ended Wideband and Balanced Bandpass Filters Loaded With Stepped-Impedance Stubs , 2017, IEEE Access.

[11]  Qinfen Xu,et al.  Slotline-Based Balanced Filter With Ultra-Wide Stopband and High Selectivity , 2020, IEEE Transactions on Circuits and Systems II: Express Briefs.

[12]  Weimin Wang,et al.  Wideband Bandpass Filtering Balun With Perfect In-Band Matching and Isolation , 2020, IEEE Transactions on Circuits and Systems II: Express Briefs.

[13]  Lei Zhu,et al.  Wideband Impedance Transformers With Good Frequency Selectivity Based on Multisection Quarter-Wave Lines and Short-Circuited Stubs , 2016, IEEE Microwave and Wireless Components Letters.

[14]  Yuanan Liu,et al.  Wideband Single-Ended and Differential Bandpass Filters Based on Terminated Coupled Line Structures , 2017, IEEE Transactions on Microwave Theory and Techniques.

[15]  Lei Zhu,et al.  Wideband Differential Bandpass Filters on Multimode Slotline Resonator With Intrinsic Common-Mode Rejection , 2015, IEEE Transactions on Microwave Theory and Techniques.

[16]  Xin Gao,et al.  High Selectivity Wideband Balanced Filters With Multiple Transmission Zeros , 2017, IEEE Transactions on Circuits and Systems II: Express Briefs.

[17]  Jian-Xin Chen,et al.  High-Selectivity Tunable Balanced Bandpass Filter With Constant Absolute Bandwidth , 2017, IEEE Transactions on Circuits and Systems II: Express Briefs.