Dual‐mode dual‐band bandpass filter design utilising cylindrical TM‐mode cavities

In this paper, a fractal-based complementary split-ring resonator (CSRR) has been introduced as a defected ground structure (DGS) in the ground plane of a dual-mode microstrip bandpass filter to produce a new compact filter with dual-band response. The conventional double square ring resonator structure is modified such that its inner ring is made with a fractal shape instead of a square. Measured and simulation results show that the resulting filter offers a dual passband response; the higher passband is attributed to the dual-mode microstrip ring structure, whereas the lower passband is as a result of the embedded CSRR DGS structure. In addition, the results show that the position of the lower passband could be varied, to a certain extent, without affecting the position of the higher passband by applying higher fractal iteration levels to the inner split ring. These features, together with the compact size the proposed filter offers, make it suitable for use in a wide variety of dual-band communication applications. Measured results, carried out on filter prototypes, have been found in agreement with those theoretically predicted.

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8 pole high temperature superconductor microstrip dual band bandpass filter design

2011 IEEE MTT-S International Microwave Symposium ◽

10.1109/mwsym.2011.5972643 ◽

2011 ◽

Author(s):

Kenneth S. K. Yeo ◽

Michael J. Lancaster

Keyword(s):

High Temperature ◽

High Temperature Superconductor ◽

Bandpass Filter ◽

Filter Design ◽

Dual Band

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New dual-band bandpass filter design based on slotted ground structures

Microwave and Optical Technology Letters ◽

10.1002/mop.26028 ◽

2011 ◽

Vol 53 (7) ◽

pp. 1505-1511

Author(s):

Xiao-Hua Wang ◽

Quan Xue ◽

Kim Fung Man

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Dual Band ◽

Ground Structures

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Compact dual-mode microstrip bandpass filter based on slotted square patch resonator

Microelectronics International ◽

10.1108/mi-08-2021-0080 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Karthie S. ◽

Zuvairiya Parveen J. ◽

Yogeshwari D. ◽

Venkadeshwari E.

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Center Frequency ◽

Dual Mode ◽

Content Type ◽

Transmission Zeros ◽

Compact Size ◽

Mode Response ◽

Better Than ◽

Good Agreement

Purpose The purpose of this paper is to present the design of a compact microstrip bandpass filter (BPF) in dual-mode configuration loaded with cross-loop and square ring slots on a square patch resonator for C-band applications. Design/methodology/approach In the proposed design, the dual-mode response for the filter is realized with two transmission zeros (TZs) by the insertion of a perturbation element at the diagonal corner of the square patch resonator with orthogonal feed lines. Such TZs at the edges of the passband result in better selectivity for the proposed BPF. Moreover, the cross-loop and square ring slots are etched on a square patch resonator to obtain a miniaturized BPF. Findings The proposed dual-mode microstrip filter fabricated in RT/duroid 6010 substrate using PCB technology has a measured minimum insertion loss of 1.8 dB and return loss better than 24.5 dB with a fractional bandwidth (FBW) of 6.9%. A compact size of 7.35 × 7.35 mm2 is achieved for the slotted patch resonator-based dual-mode BPF at the center frequency of 4.76 GHz. As compared with the conventional square patch resonator, a size reduction of 61% is achieved with the proposed slotted design. The feasibility of the filter design is confirmed by the good agreement between the measured and simulated responses. The performance of the proposed filter structure is compared with other dual-mode filter works. Originality/value In the proposed work, a compact dual-mode BPF is reported with slotted structures. The conventional square patch resonator is deployed with cross-loop and square ring slots to design a dual-mode filter with a square perturbation element at its diagonal corner. The proposed filter exhibits compact size and favorable performance compared to other dual-mode filter works reported in literature. The aforementioned design of the dual-mode BPF at 4.76 GHz is suitable for applications in the lower part of the C-band.

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