BAND NOTCH CHARACTERSTICS OF A ULTRA WIDE BAND ANTENNA USING U SLOT Rachana Khandelwal 1, Rajveer Singh 2 1 Electronics & Communication, Rajasthan College of Engineering For Women, (India) 2 Electronics & Communication, Rajasthan college of Engineering for Women, (India) ABSTRACT In this paper a UWB antenna is designed in which frequency notch is present. By inserting an U slot in the nearly rectangular patch notch band can be obtained. It gives VSWR < 2 for whole UWB band except notch band. For proper UWB band response and perfect notch band we are taking optimum width of partial ground, patch and U shaped slot. For this we are taking a substrate with dielectric constant r=4.1 and height of substrate =1.5mm.Total size of structure is 40 40mm². Keywords: Patch Antenna, Notch Band, Slot, UWB, Partial Ground. I INTRODUCTION UWB as name refers it called Ultra Wide Band antenna has gain a lot of area of interest due to its large bandwidth and other lot of advantage like omnidirectional radiation pattern, low cost and simple structure. It cover large band from (3.1-10.6) GHz frequency, but main drawback of this band is that in this band a (5.15-5.85)GHz band is used by WLAN and to get good results of from UWB band this band should be rejected.for this band notch characteristics are used and various types of antenna is suggested For this [2-4]. A lot of different shape slots are able to suppress a band slot are U, circular,rectangular, triangular can reject WLAN band.mainly UWB technology is developed by US deptt. Of defence in 1960.It also gives transmission speed 10 time more than WLAN. [1].According to federal communication commission frequency band of UWB (3.1-10.6) GHz in 2002 for use in indoor & outdoor handheld system [5].UWB is far more better than the traditional technologies due to its advantage and a simple and optimized UWB antenna can give better notch omnidirectional properties, gain and group delay. [6] In this paper we design a UWB antenna with partial ground, patch that is nearly rectangular and an U shape slot. Without slot antenna cover whole UWB band and by inserting slot it gives notch in WLAN band. Antenna is simulated by CST microwave studio 5 and optimum dimensions are taken to get proper notch and response less than -10dB.Antenna is fabricated on substrate having r=4.1 & thickness of substrate is =1.5mm. 489 P a g e
II. ANTENNA DESIGN The structure and design of the proposed ultra-wideband (UWB) antenna with a band-notch slot feature is shown in Figure 1.The antenna is fabricated on a FR4 substrate that has dielectric constant=4.1 and height =1.5mm The whole area covered by the antenna is 40 40mm². Antenna design contain a partial ground, U slot and patch that is nearly look like rectangular and a feed line having 50Ω characteristics impedance. Without notch only UWB band can be achieved and by inserting slot the notch can be obtained. For proper notch the length and width of antenna and slot should be adjusted. 490 P a g e
VSWR s-parameter III RESULT The proposed antenna is simulated and return loss has been measured, and VSWR curve has been plotted. Without slot only UWB band has been obtained and by inserting a slot UWB with notch can be obtained. Designed antenna is simulated using CST microwave studio. By taking optimum dimension value of curve is less than -10dB for whole UWB band / 0-5 -10-15 -20-25 -30-35 2 4 6 8 10 12 Frequency(GHz) Fig. (5) S parameter curve of antenna / 18 16 14 12 10 8 6 4 2 0 2 4 6 8 10 12 frequency/ghz Fig. (6) VSWR curve for antenna 491 P a g e
Fig. (7) E Field at f =6 GHz Fig. (8) Field at f=6 GHz IV CONCLUSION Micro strip antenna is designed with nearly rectangular patch and U shape slot to get UWB and WLAN notch.by simulated results we get perfect notch and UWB band with Omnidirectional radiation pattern by this we know that this antenna is good in response.so this can used in UWB devices in future. REFERENCES Journal papers: [1].A planar half circle shaped UWB notch antenna design by Hyo K Lee, Jung N Jee Jong K park.. [2].Y Kim, D H kwon, CPW feed planar UWB antenna have a frequency notch function electron letter 40(2004)403-405. [3].KL Wong, YW Chi, CM Su, FS chang band notch UWN circular disk monopole antenna via an arc shape slot Opt Techno letter 4592005)1881-191. [4].J.N.Lee & J.K park Imp characteristics of trapezoidal UWB antenna with notch Function MW opt techno letter 46(2005) 503-506. 492 P a g e
[5].Chin Fang Tseng planar UWB dipole antenna with band notch characteristics IEEE 2009 PP 1825-1828. [6].Ma, T. G. and S. K. Jeng, A printed dipole antenna with tapered slot feed for ultra-wide-band applications," IEEE Trans. Antennas Propag. Vol. 53, 3833{3836, Nov.2005 [7] D. Valderas,J. Melendez,and I. Sancho, Some design consideration for antennas in UWB wireless Commnitation system, IEEE International Symposium on antennas and Propagation,vol. 1, June 2003 pp.822-825. [8] L.H.Ye and Q.-X chu,3.5/5.5 GHz dual band notch ultra wideband slot antenna with compact size, Electronics Letter,vol.46,no.54,Mar.2010. Books: [9] Fedaral Communication Commission,Washington,DC, FCC Report and order on ultra wideband technology,2002. 493 P a g e