International Journal of Electrical and Computer Engineering (IJECE) Vol. 7, No. 5, October 2017, pp. 2420~2425 ISSN: 2088-8708, DOI: 10.11591/ijece.v7i5.pp2420-2425  2420 Journal homepage: http://iaesjournal.com/online/index.php/IJECE A Compact UWB BPF with a Notch Band using Rectangular Resonator Sandwiched between Interdigital Structure Yatindra Gaurav 1 , R.K. Chauhan 2 Departement of Electronics and Communication Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, UP, India Article Info ABSTRACT Article history: Received Sep 6, 2016 Revised Jun 7, 2017 Accepted Aug 11, 2017 This paper presents a compact design of an ultra wide band bandpass filters with a notch band using interdigital structure. The aim of the design is to reduce the size of filter, reduce the complexity of the design, and improve the performance of filter response. The proposed filter comprises of a rectangular resonator sandwiched between Interdigital structures, with rectangular slot as defected microstrip structure at the input and output ports. This design has been used for the first time to achieve the above aim. The advantage with this design is that, it does not use any via or defected ground structure. The insertion loss of proposed filter, in passband between 3.1 GHz to 10.8 GHz, is less than 0.7dB, and for the notched band it is 21.5 dB centred at 7.9 GHz. The proposed filter is fabricated, tested and compared with simulated results. The proposed design was small in size with less complexity, and shows performance better than the other designs available in the literatures at this dimension. Keywords: Interdigital structure Ultra wide band Bandpass filter Notch band Rectangular resonator Rectangular slot Copyright © 2017 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: R. K. Chauhan, Departement of Electronics and Communication Engineering, Madan Mohan Malaviya University of Technology, Gorakhpur, Uttar Prdesh, India. Email: rkchauhan27@gmail.com 1. INTRODUCTION Ultra-Wideband (UWB) devices and systems have attracted the attention since the Federal Communications Commission has released the unlicensed use of the frequency spectrum 3.1 - 10.6 GHz for UWB applications in 2002 [1]. High performance and compact size are the two important issues that has been an active area of research in the last decade [2], [3], [4], [5], [6] and [7]. For high performances algorithm methods and modified ground plane method is being used recently for various ultra wide band application [8] and [9]. The investigation on UWB bandpass filter, which is one of the main components of UWB communication systems, has been a subject of interest. Several UWB Filters has been proposed and implemented recently [10], [11], [12] and [13]. Earlier the focus was on the passband requirement, but later on research shifted towards the addition of notch within the passband. To realize a notch band in UWB BPF, several techniques has been proposed in the last few years. In one of the work, a coplanar waveguide (CPW) technique is used to obtain a notch band [14]. A ring resonator with two stepped impedance stubs as well as multiple slotline resonators has been used to create a notch band in UWB BPF [15] and [16]. A compact UWB BPF has been realized recently for better notch band characteristics using dual stub loaded resonator and folded T-shaped stepped impedance resonator [17] and [18]. However, all the above designs shows good response to return loss and insertion loss but have a drawback of larger area and complexity in design that leads to increase in number of fabrication steps. For reducing the size of UWB BPF with a notch band, defected ground structures were used in the design by several researchers [19]. Such structure shows improved filter performance, but the drawback is that its