STUDY ON EBG STRUCTURES AND APPLICATION IN UWB PASS FILTER

Transcription

1 STUDY ON EBG STRUCTURES AND APPLICATION IN UWB BAND PASS FILTER Sridhar Raja. D Asst. Professor, School of electronics engineering Bharath university. Abstract This paper aims to reports the different EBG Structure and some of these application in field of micro strip antenna and filters.also one of the EBG structure as been proposed to obtain compact UWB band pass filter.the simulation as been done using Agilent ADS software. Index Terms Electromagnetic bandgap (EBG), ultra wideband (UWB). I.INTRODUCTION Electromagnetic Band gaps (EBG) have emerged as a new technology which makes possible the design of more compact filters.in recent years, electromagnetic band gap (EBG) structures have become very attractive to researchers and engineers in the field of wireless components such as antennas, and filters. The EBG structures are the microwave counterpart of the well-known photonic band gap (PBG) structures, and have many applications. In addition to antenna and filter applications, EBG structures have also attracted attention from researchers in the area of noise management in mixed-signal systems also. II.OVERVIEW OF EBG STRUCTURES Periodic structures are abundant in nature, which have fascinated artists and scientists alike. When they interact with electromagnetic waves, exciting phenomena appear and amazing features result. In particular, characteristics such as frequency stop bands, pass bands, and band gaps could be identified. Electromagnetic band gap structures are defined as artificial periodic (or sometimes nonperiodic) objects that prevent/assist the propagation of electromagnetic waves in a specified band of frequency for all incident angles and all polarization states. Electromagnetic band-gap (EBG) structures are periodic structures which can prohibit the propagation of electromagnetic wave in certain band of frequency. They can be embedded in the dielectric substrate or etched on the metal layers. The EBG structures are always used to help suppress the surface waves to gain good pass band or stop band. There are two types of EBG structure to be discussed. Firstly is Perforated dielectric and the second one is Metallodielectric structures. Perforated dielectric is defined as effectively suppress unwanted substrate mode. This structure designed by drill periodic holes on dielectric subtracts to introduce another dielectric but in practical, this structure is difficult to implement. Metallodielectric structure is exhibits an attractive reflection phase future where the reflected field change continuously ISSN: Page 5

2 from 180 degrees to -180 degrees versus frequency. III SOME DIFFERENT EBG STRUCTURES EBG structures are usually realized by periodic arrangement of dielectric materials and metallic conductors. In general, they can be categorized into three groups according to their geometric configuration: (1) Three-dimensional volumetric structures, (2) Two-dimensional planar surfaces, and (3) One-dimensional transmission lines. Uni-planar Mushroom-like Fork-like Fig 1. Two-dimensional planar surfaces EBG. Fig.2 Proposed Uni-planar EBG structure ISSN: Page 6

3 Woodpile dielectric multi-layer metallic tripod Fig.3 Three-dimensional volumetric structures IV.BASIC PRINCIPLE OF EBG STRUCTURE The basic design of EBG structure is shown in figure 4 known as mushroom like EBG structure. This structure has frequency range where the surface impedance is very high. The equivalent LC circuit acts as a two-dimensional electric filter in this range of frequency to block the flow of the surface waves.. The inductor L results from the current flowing through the visa, and the capacitor C due to the gap effect between the adjacent patches. Thus, the approach to increase the inductance or capacitance will naturally result in the decrease of band-gap position. Figure 4: 2D EBG structure. Central frequency of the band gap is given by; f c = 1/(2π LC) where ISSN: Page 7

4 The bandwidth of the electromagnetic band gap is given by; V.APPLICATION OF EBG STRUCTURE In this application the proposed EBG structure is taken to design an UWB band pass filter. designed on an RT/Duroid 3010 substrate with a dielectric constant of 10.2 and thickness of mm. The inter digital coupled lines used all BPFs have a coupling peak at the center frequency of 6.85 GHz..here the bandpass fiter is designed using EBG mainly for compactness. Fig 5. Schematics of proposed EBG Structure application on UWB filter. V.SIMULATION RESULTS GHz Fig 6. Return loss ISSN: Page 8

5 GHz Fig.7 Insertion loss VII.CONCLUSION In this paper different EBG structures are investigated and applied to UWB BPFs. The EBG application in UWB band pass filter is simulated using ADS Momentum simulator. The proposed UC EBG cell,used here as improved passband obtained in UWB region,also improving the good out-of-band performances and the EBG structure to reduce the overall size of the filter.the next work is on periodic UC-EBG structure filter and compare with Embedded Multi Mode Resonator UWB BPF. REFERENCE [1]FCC, Revision of Part 15 of the Commission s Rules Regarding Ultra-Wideband Transmission Systems Federal Communications Commission, Tech. Rep. ET-Docket , FCC02-48, Apr [2] H. Ishida and K. Araki, Design and analysis of UWB bandpass filter, in Proc. IEEE Top. Conf. Wireless Comm. Tech., Oct. 2003, pp [3] C.-L. Hsu, F.-C. Hsu, and J.-T. Kuo, Microstrip bandpass filters for ultra-wideband (UWB) wireless communications, in IEEE MTT-S Int.Dig., Jun. 2005, pp [4] W. Menzel, M. S. R. Tito, and L. Zhu, Low-loss ultra-wideband (UWB) filters using suspended stripline, in Proc. Asia-Pacific Microw.Conf., Dec. 2005, vol. 4, pp ISSN: Page 9

6 [5] Electromagnetic Band Gap Structures in Antenna Engineering. FAN YANG University of Mississippi [6] J.-S. Hong and H. Shaman, An optimum ultra-wideband microstrip filter, Microw. Opt. Technol. Lett., vol. 47, no. 3, pp , Nov [7] L. Zhu, S. Sun, and W. Menzel, Ultra-wideband (UWB) bandpass filters using multiple-mode resonator, IEEE Microw. Wireless Compon.Lett., vol. 15, no. 11, pp , Nov [8]F.-R. Yang, K.-P. Ma, Y. Qian, and T. Itoh, A uniplanar compact photonic-bandgap (UC-PBG) structure and its applications for microwave circuit, IEEE Trans. Microw. Theory Tech., vol. 47, no. 8,pp , Aug ISSN: Page 10