Design of differential mode wideband bandpass filter with Common mode suppression using modified branch line coupler

Synthesis of differential-mode bandpass filter (BPF) with good common-mode suppression has been described and demonstrated on the basis of ring dielectric resonator (RDR) for high-performance communication system. A RDR with two pairs of feeding lines has been used to excite TE01δ-mode. This unique combination of feeding lines and the ring resonator creates a differential passband. Meanwhile, TM01δ-mode of the DR can also be excited to achieve common-mode rejection in the stopband. Transmission zeros are created in the lower and upper stopband to further improve the selectivity of the proposed BPF. A second-order differential BPF is designed, fabricated and its performance is measured to validate the concept. There is good agreement between simulated and measured results.

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A Differential-Mode Wideband Bandpass Filter With Enhanced Common-Mode Suppression Using Slotline Resonator

IEEE Microwave and Wireless Components Letters ◽

10.1109/lmwc.2012.2218279 ◽

2012 ◽

Vol 22 (10) ◽

pp. 503-505 ◽

Cited By ~ 84

Author(s):

Yen-Ju Lu ◽

Shih-Yuan Chen ◽

Powen Hsu

Keyword(s):

Bandpass Filter ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression

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Tunable Balanced Bandpass Filter with High Common-mode Suppression Based on SLSRs

Frequenz ◽

10.1515/freq-2016-0357 ◽

2017 ◽

Vol 71 (11-12) ◽

Author(s):

Feng Wei ◽

Xin Yi Wang ◽

Dun Wei Liao ◽

Xiao Wei Shi

Keyword(s):

Frequency Band ◽

Design Theory ◽

Bandpass Filter ◽

Design Procedure ◽

Operating Frequency ◽

Differential Mode ◽

Common Mode ◽

Operating Frequency Band ◽

Mode Suppression ◽

Transition Structures

AbstractA tunable balanced bandpass filter (BPF) with a good common-mode (CM) suppression based on slotline resonators is proposed in this letter. Two novel stub-loaded slotline resonators (SLSRs) terminated with varactors are designed to obtain tunable differential-mode (DM) responses. It is found that a high and wideband CM suppression can be achieved by employing balanced stepped-impedance microstrip-slotline transition structures. Moreover, the DM passbands are independent from the CM ones, which can significantly simplify the design procedure. To validate the design theory, a compact tunable balanced BPF with an operating frequency band ranging from 3.09 GHz to 3.6 GHz is designed and fabricated. The measured results are found to agree well with the simulated ones.

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Differential‐mode bandpass filter on microstrip line with wideband common‐mode suppression

Electronics Letters ◽

10.1049/el.2016.4223 ◽

2017 ◽

Vol 53 (3) ◽

pp. 163-165 ◽

Cited By ~ 6

Author(s):

Dong Chen ◽

Lei Zhu ◽

Huizheng Bu ◽

Chonghu Cheng

Keyword(s):

Microstrip Line ◽

Bandpass Filter ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression

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A Compact Differential-Mode Wide Stopband Bandpass Filter with Good and Wideband Common-Mode Suppression

Wireless Communications and Mobile Computing ◽

10.1155/2018/4032183 ◽

2018 ◽

Vol 2018 ◽

pp. 1-4

Author(s):

Gang Zhang ◽

Yang Zhao ◽

Wei Yan

Keyword(s):

Transmission Lines ◽

Bandpass Filter ◽

Experimental Results ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression ◽

Microstrip Transmission Lines

This letter presents a microstrip differential-mode (DM) bandpass filter (BPF) with high and wide stopband suppression under both DM and common-mode (CM) operations. A new coupling topology is formed up to realize the DM BPF by integrating a pair of λ/2 microstrip transmission lines and two multimode resonators. The DM and CM equivalent half-circuits are established to explain the operating principal. For validation, a DM BPF operating at 2.2 GHz is implemented. Experimental results indicate that the presented DM BPF exhibits not only sharp DM passband selectivity but also deep and ultrawide stopband suppression of more than 30 dB for both DM and CM.

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A Dual-Wideband Balanced Bandpass Filter Based on Branch-Line Structure With Controllable Common-Mode Suppression

Frontiers in Physics ◽

10.3389/fphy.2021.764648 ◽

2021 ◽

Vol 9 ◽

Author(s):

Baoping Ren ◽

Xinlei Liu ◽

Xuehui Guan ◽

Mengrou Xu ◽

Zhi-Chong Zhang

Keyword(s):

Bandpass Filter ◽

Design Method ◽

Third Order ◽

Common Mode ◽

Branch Line ◽

Line Structure ◽

Mode Suppression ◽

Transmission Zeros ◽

Synthesis Design ◽

Mode Method

In this paper, a novel dual-wideband balanced bandpass filter (BPF) based on branch-line structure is proposed. For analysis, the equivalent circuits of differential-mode (DM) and common-mode (CM) of the filter are built based on the even- and odd-mode method. With a proper synthesis design of DM bisection, dual passbands with a multi-order filtering response can be obtained. Additionally, three open-circuited stubs are centrally loaded on the CM bisection and six controllable transmission zeros are therefore generated. Thus, two stopbands are formed and then a favorable CM suppression within DM passbands is obtained. For demonstration, a third-order dual-wideband balanced BPF is designed with two passbands operating at 2.54 and 4.62 GHz. Good agreement between the simulated results and measured results is obtained, which verifies the validity of the proposed design method.

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Tunable balanced to balanced filtering power divider with high common-mode suppression

Frequenz ◽

10.1515/freq-2019-0178 ◽

2020 ◽

Vol 74 (7-8) ◽

pp. 263-270

Author(s):

Cao Zeng ◽

Xue Han Hu ◽

Feng Wei ◽

Xiao Wei Shi

Keyword(s):

Return Loss ◽

High Selectivity ◽

Power Divider ◽

Center Frequency ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression ◽

The Common ◽

Equal Power ◽

Good Agreement

AbstractIn this paper, a tunable balanced-to-balanced in-phase filtering power divider (FPD) is designed, which can realize a two-way equal power division with high selectivity and isolation. A differential-mode (DM) passband with a steep filtering performance is realized by applying microstrip stub-loaded resonators (SLRs). Meanwhile, six varactors are loaded to the SLRs to achieve the center frequency (CF) and bandwidth adjustment, respectively. U-type microstrip lines integrated with stepped impedance slotline resonators are utilized as the differential feedlines, which suppress the common-mode (CM) intrinsically, making the DM responses independent of the CM ones. A tuning center frequency from 3.2 to 3.75 GHz and a fractional bandwidth (12.1–17.6%) with more than 10 dB return loss and less than 2.3 dB insertion loss can be achieved by changing the voltage across the varactors. A good agreement between the simulated and measured results is observed. To the best of authors' knowledge, the proposed balanced-to-balanced tunable FPD is first ever reported.

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