Quarter Wave Resonator based Microstrip Bandpass Filter using Asymmetrical coefficients
Thiyagarajan Krishnan1, Allin Joe D2, Venkatesh D3, Pandiyalakshmi K4

1Thiyagarajan Krishnan*, Associate Professor, Department of Electronics and Communication Engineering, VelTech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Chennai, Tamil Nadu, India.
2Allin Joe D, Assistant Professor, Department of Electronics and Communication Engineering, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, India.
3Venkatesh D, Assistant Professor (Senior Grade), PSG Institute of Technology and Applied Research, Coimbatore, Tamil Nadu, India.
4Pandiyalakshmi K, Senior Software Engineer, Delphi Propulsion Systems Pvt Ltd, Bengaluru.

Manuscript received on November 18, 2019. | Revised Manuscript received on 28 November, 2019. | Manuscript published on December 10, 2019. | PP: 3319-3324 | Volume-9 Issue-2, December 2019. | Retrieval Number: B7649129219/2019©BEIESP | DOI: 10.35940/ijitee.B7649.129219
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: This paper presents a new concept of bandpass filter design based on quarter-wave resonator which covers ISM band (2.4-2.48 GHz) can be used for applications such as wireless fidelity (Wi-Fi) and Global System for Mobile communication (GSM). A fifth-order Butterworth bandpass filter is designed using standard filter coefficients with fractional bandwidth of 50% for the center frequency of 2.1 GHz. Filter design is achieved using quarter-wave resonator, and the obtained response satisfies the desired filter specifications. The insertion loss of 21 dB is achieved at the cutoff frequency of 2.1 GHz. The passband frequency of 1.877 GHz to 2.772 GHz is achieved in the proposed design. The standard coefficients of the Butterworth filter were modified to propose a new type of asymmetrical filter coefficients. The designed filter has better response than existing method in terms of bandwidth and insertion loss. The designed Bandpass filter has a passband frequency of 1.8 GHz to 2.7 GHz. Therefore, the designed bandpass filter can be used for both Wi-Fi and GSM applications simultaneously. 
Keywords: Bandpass Filter (BPF), Microstrip, Butterworth, Quarter-wave Resonator.
Scope of the Article: Microstrip Antenna