Bandpass Filter Design using the Square Loop Resonator on 3 GHz Frequency for Radar Applications

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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Substrate Integrated Waveguide with Tapered Electromagnetic Bandgap Structures for Bandpass Filter Design

2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) ◽

10.1109/nemo.2018.8503195 ◽

2018 ◽

Author(s):

Farouk Grine ◽

Mohamed Taoufik Benhabiles ◽

Rostom Khalef ◽

Tarek Djerafi ◽

Mohamed Lahdi Riabi

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Substrate Integrated Waveguide ◽

Electromagnetic Bandgap

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A novel eigenmode-based neural network for fully automated microstrip bandpass filter design

2017 IEEE MTT-S International Microwave Symposium (IMS) ◽

10.1109/mwsym.2017.8058947 ◽

2017 ◽

Cited By ~ 4

Author(s):

Masataka Ohira ◽

Ao Yamashita ◽

Zhewang Ma ◽

Xiaolong Wang

Keyword(s):

Neural Network ◽

Bandpass Filter ◽

Filter Design

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A semi-lumped microstrip UWB bandpass filter

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078709000117 ◽

2009 ◽

Vol 1 (1) ◽

pp. 57-64 ◽

Cited By ~ 1

Author(s):

Darine Kaddour ◽

Jean-Daniel Arnould ◽

Philippe Ferrari

Keyword(s):

Group Delay ◽

Bandpass Filter ◽

Filter Design ◽

Sensitivity Study ◽

Critical Parameters ◽

Center Frequency ◽

Pass Filter ◽

Low Pass Filter ◽

Low Pass ◽

High Pass

In this paper, a miniaturized bandpass filter for ultra-wide-band applications is proposed. It is based on the embedding of high-pass structures in a low-pass filter. A semi-lumped technology combining surface-mounted capacitors and transmission lines has been used. The filter design rules have been carried out. Furthermore, two filters having a 3-dB fractional bandwidth of 142 and 150%, centered at 0.77 and 1 GHz, respectively, have been realized for a proof of concept. Measured characteristics, in good agreement with simulations, show attractive properties of return loss (|S11| <−18 dB), insertion loss (<0.3 dB), and a maximum group delay and group delay variation of 2 and 1.3 ns, respectively. A distributed filter based on the same low-pass/high-pass approach has been also realized and measured for comparison. The size reduction reaches 85% for the semi-lumped filter, and its selectivity is improved with a shape factor of 1.3:1 instead of 1.5:1. The semi-lumped filter's drawback is related to a smaller rejection bandwidth compared to the distributed one. To improve the high-frequency stopband, an original technique for spurious responses suppression based on capacitively loaded stubs has been proposed. Even if the performances do not reach that obtained for the distributed approach, with this technique spurious responses are pushed until eight times the center frequency. A sensitivity study vs. critical parameters has also been carried out, showing the robustness of the design.

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