Discussion of conversion theory between mixed-mode S-parameters and T-parameters for differential circuit with and without common-mode suppression

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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Design of differential-mode bandpass filter with common-mode suppression using ring dielectric resonator

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078716001306 ◽

2016 ◽

Vol 9 (5) ◽

pp. 1029-1035 ◽

Cited By ~ 2

Author(s):

Jugul Kishor ◽

Binod K. Kanaujia ◽

Santanu Dwari ◽

Ashwani Kumar

Keyword(s):

Dielectric Resonator ◽

High Performance ◽

Bandpass Filter ◽

Ring Resonator ◽

Differential Mode ◽

Common Mode ◽

Mode Suppression ◽

Transmission Zeros ◽

System A ◽

Good Agreement

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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