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Fractal-based triangular bandpass filter with a notched band for interference rejection in wideband applications

Karthie S. (Department of ECE, Sri Sivasubramaniya Nadar College of Engineering, Chennai, India)
Salivahanan S. (Department of ECE, Sri Sivasubramaniya Nadar College of Engineering, Chennai, India)

Circuit World

ISSN: 0305-6120

Article publication date: 6 August 2019

Issue publication date: 21 August 2019

Abstract

Purpose

This paper aims to present the design of a novel triangular-shaped wideband microstrip bandpass filter implemented on a low-cost substrate with a notched band for interference rejection.

Design/methodology/approach

The conventional dual-stub filter is embedded with simple fractal-based triangular-circular geometries through various iterations to reject wireless local area network (WLAN) signals with a notched band at 5.8 GHz.

Findings

The filter covers a wide frequency band from 3.1 to 8.8 GHz and has a fractional bandwidth of 98 per cent with the lower passband of 57.5 per cent and upper passband of 31.6 per cent separated by a notched band at 5.8 GHz. The proposed wideband prototype bandpass filter is fabricated in FR-4 substrate using PCB technology and the simulation results are validated with measurement results which include insertion loss, return loss and group delay. The fabricated filter has a sharp rejection of 28.3 dB at 5.8 GHz. Measured results show good agreement with simulated responses. The performance of the fractal-based wideband filter is compared with other wideband bandpass filters.

Originality/value

In the proposed work, a fractal-based wideband bandpass filter with a notched band is reported. The conventional dual-stub filter is deployed with triangular-circular geometry to design a wideband filter with a notched band to suppress interference signals at WLAN frequency. The proposed wideband filter exhibits smaller size and better interference rejection compared to other wideband bandpass filter designs implemented on low-cost substrate reported in the literature. The aforementioned wideband filter finds application in wideband wireless communication systems.

Keywords

Citation

S., K. and S., S. (2019), "Fractal-based triangular bandpass filter with a notched band for interference rejection in wideband applications", Circuit World, Vol. 45 No. 3, pp. 141-147. https://doi.org/10.1108/CW-06-2018-0045

Publisher

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Emerald Publishing Limited

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