International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 04 | Apr 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 5965 Multilayer Tapered U-shape EBG Low Pass Filter Deepti Gupta 1 , P. K. Singhal 2 1&2 Department of Electronics Engineering, Madhav Institute of Technology and Science, Gwalior, 474 005, India ---------------------------------------------------------------------***---------------------------------------------------------------------------- Abstract. In this paper a Multi-layered U-shaped Electromagnetic Band Gap (EBG) low pass filter is proposed. A design for prominent stop band characteristics with minimized ripples is presented, while maintaining the filter pass-band performance. By properly designing and integrating the tapering techniques with the low pass filter, the proposed structure exhibit superior pass band and stop band characteristics. By designing the microstrip line in U- shape the circuit area is reduced significantly and due to this shape the pass band ripples are suppressed to a large extent. Since the design is multi-layered, no structure is designed at the ground plane so the problem of distortion of ground plane structure while packaging is resolved. The measured results indicate that the proposed structure achieves significantly improved band characteristics with minimum distortion. Keywords: Multilayer, Tapered U-shape, Low Pass Filter, Microstrip Line, Electromagnetic Band Gap 1. Introduction A Microwave filter is a two port network used to control the frequency response at a certain point in a microwave system [1]. More specifically a low pass filter is a filter that passes low frequency signals but attenuates signals with frequencies higher than cut off frequency as shown in Fig.1. In this paper a multi-layered U-shaped electromagnetic band gap (EBG) low pass filter which works at 2.5 GHz is proposed. A design for prominent stop band characteristics with minimized ripples is presented, while maintaining the filter pass-band performance. By properly designing and integrating the tapering techniques with the low pass filter, the proposed structure exhibit superior pass band and stop band characteristics. By designing the microstrip line in U- shape the circuit area is reduced significantly and due to this shape the pass band ripples are suppressed to a large extent. Since the design is multi-layered, no structure is designed at the ground plane so the problem of distortion of ground plane structure while packaging is resolved. In a traditional straight one-dimensional (1-D) EBG microstrip structure [2], a good stopband performance is usually obtained by increasing the number or the size of EBG cells, thus resulting in an increase in the circuit area. These EBG structures have cells in a single plane. They are a compromise between good filtering performance and compact physical size. The problem above was well addressed by introducing multiple bends in the MLIN giving rise to an EBG filter structure with an excellent rejection band in a relatively small physical size [3]. Fig. 1 Response of low pass filter In this paper, a novel high-performance compact DP-EBG (Dual Planar-EBG) micro strip low-pass filter structure with U-shaped MLIN geometry is proposed and implemented. With the unique U-shaped geometry of the MLIN and the DP-EBG configuration with a reduction in the width of the MLIN, as well as the adopted Chebyshev tapering distribution, the proposed filter structure demonstrates a high selectivity, a low ripple level in the passband. 2. Electromagnetic Band Gap Structures (EBG) The Electromagnetic Band Gap (EBG) structure has been a term widely accepted today to call the artificial periodic structure that prohibits the propagation of electromagnetic waves in certain frequency bands at microwave or millimeter wave frequencies. These periodic structures were originally proposed at optical frequencies and are known as a photonic band gap (PBG) structure or photonic crystal (PC). Analogous to crystals where periodic arrays of atoms produce band gaps in which the propagation of photon is prohibited, an artificial periodic structure is comprised of periodic macroscopic cells. These periodic structures are scalable over a wide frequency range in the electromagnetic spectrum. Due to their scalability, research has progressed into the range of microwave and millimeter wave, infrared [5]. It has been widely applied as the substrate of planar microwave circuits such as patch antennas to suppress the surface waves, and power amplifiers to reduce the harmonics [6].The unique feature of EBG structures is the existence of the band gap where electromagnetic waves are