Notch band antenna with integrated microstrip open loop resonator for UWB application

International Journal of Advanced Engineering Research and Technology (IJAERT) Volume 2 Issue 6, September 2014, ISSN No.: 2348 – 8190

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Notch band antenna with integrated microstrip open loop resonator for

UWB application

Anjali Gupta*, Deshdeep Gupta** * Masters of technology, U.P.T.U. Lucknow, Bareilly

** Masters of technology, U.P.T.U. Lucknow, Bareilly

ABSTRACT This letter proposes a novel printed monopole antenna

for ultra wide band (UWB) applications with notch

band characteristics. UWB system requires band notch

filters in order to prevent sensitive components.

Recently these filters can be integrated into the UWB

antenna. This work presents a new method to generate

a band notched characteristics, we use an open loop

resonator which is located on the back side of the

substrate. A simulation was done and good results

have been obtained with notched band at 5.1 GHz

WLAN.

Keywords - Coplanar waveguide, Monopole antenna,

Open loop resonator, UWB antenna.

1. INTRODUCTION

In the last few years, the ultra wide band (UWB)

technology has been developed widely and rapidly.

Commercial UWB system requires small low cost

antennas with omnidirectional radiation patterns and

large bandwidth [1]. There is a much interest in the

use of ultra wide band (UWB) signals from 3.1 to 10.6

GHz for short range, high data rate communications

[3]. It is a well known fact that planar monopole

antennas present really appealing physical features

such as simple structure, small size, and low cost. Due

to all these interesting characteristics, planar monopole

antennas are extremely attractive to be used in

emerging UWB applications and growing research

activity. UWB ground penetrating radar can be used to

detect mines and damaged utility pipes. UWB radar

systems

have been used to detection of early stage breast

cancer [1], [2]. Interference from a strong narrow band

signals within the UWB could overload the receiver

and band stop filters have been suggested to remove

this interference. This filter connected in series with

the antenna, might be a separate component [3], which

will increase the size, weight and complexity of system

or it could be integrated into the antenna’s feed line

[4]. A substrate integrated waveguide (SIW) cavity

filter is used in [4] within the feed line of UWB

antenna but antenna performance degradations result.

An alternative is to integrate some band stop filter into

the radiating element. A further disadvantage

associated with some of the designs is that the

geometry is complex and three dimensional [4], [6].

This communication presents a new approach for

producing a notch band within an UWB antenna. The

key innovation is to situate the notch band resonator on

the rear of the substrate which is used to support the

UWB antenna. The communication is laid out as

follows: Section II describes the antenna design, and

principles of device operation. Key results, such as the

return loss performance, VSWR, radiation pattern and

gain are provided in sections III and IV.

2. ANTENNA DESIGN

The new antenna is based around an UWB circular

disk monopole [8]. A micro strip open loop resonator

is employed to produce a frequency band notch. The

disk monopole is etched into the front side of the

substrate while the micro strip open loop resonator is

etched onto the backside. This resonator is shaded

black in Fig. 1

Fig.1: Structure of the proposed antenna

In order to produce a band notch having high quality

factor the design is printed onto a high permittivity

Rogers 3010 substrate material (ε = 10.2) having

thickness of 0.635mm. The disk monopole is fed using

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a short section of coplanar waveguide (CPW)

transmission line. The signal line is 1.93 mm wide and

the two longitudinal gaps are of 0.5mm; giving the

CPW lines an impedance of 50 Ω. A micro strip open

loop resonator has been used to create microwave

filter. If the gap is set to a small value a fourth order

mode is strongly excited. This is a major disadvantage

which effectively degrades the return loss of the

antenna towards the upper end of the frequency band.

By increasing the gap length it was possible to remove

this limitation.

The optimal dimensions of designed antenna are as

follows: b = 5.5 mm, d = 11.52 mm, g = 6.52 mm, w =

1.4 mm, Gray = metal layer 1, Black = metal layer 2,

radius of the circular disk = 12.375 mm.

3. RESULTS AND DISCUSSION

The parameters of the proposed antenna are studied by

changing one parameter at a time and fixing the others.

To fully understand the behavior of the antenna’s

structure and to determine the optimum parameters,

the antenna was analyzed using Ansoft HFSS. The

optimize value of each physical dimensions of the

proposed antenna are shown in the Fig.1. The micro

strip open loop resonator is positioned above a point

on the disk where the surface current splits equal

streams which flow in opposing directions. The

currents cancel perfectly in the center of the resonator

leading to a null consequently the resonator is only

capable of supporting a surface current distribution

which is even, that is to say symmetrical, about the

center line. For the resonator dimensions, specified in

Fig.1

Fig.2: Designed structure

Fig.3: Return loss performance of the antenna

Fig.4: VSWR of the antenna

Fig.5: Radiation pattern at 5.5 GHz

Fig.6: Radiation pattern at 8 GHz

3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00Freq [GHz]

-35.00

-30.00

-25.00

-20.00

-15.00

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-5.00

0.00

dB

(S

(1

,1

))

HFSSDesign2XY Plot 4 ANSOFT

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dB(S(1,1))Setup1 : Sw eep

3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00Freq [GHz]

0.00

2.00

4.00

6.00

8.00

10.00

11.25

VS

WR

(1

)


Curve Info

VSWR(1)Setup1 : Sw eep



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Fig.7: 3D polar plot of the antenna

Fig.8: Simulated peak gain of the antenna

3.1. Return loss

Fig.3 plots a return loss as a function of frequency.

There is good simulation results, through out the FCC

UWB band. In simulation the return loss at the 5.1

GHz, is -1.28 dB. The result suggest that the antenna

provides a high level of rejection to signal frequencies

within the notch band. The UWB antenna provides a -

10 dB return loss bandwidth which extends from

3GHz to 5.1GHz; where it is intterrrupted by the notch

band. At frequencies above the notch band the

antenna provides a -10 dB return loss bandwidth which

extends from 5.8GHz to 10.6GHz. This is sufficient to

cover the majority of the bandwidth which was

allocated by the FCC, for license exempt UWB

systems.

3.2. VSWR

Fig.4 shows the simulated VSWR characteristics of the

proposed antenna. The antenna has the frequency band

of 3 to over 11 GHz with one rejection band around

5 - 5.8 GHz. At 5.5 GHz the VSWR is 7.8 GHz,

therefore antenna will stop working at this band of

frequency.

All of the simulation results, reported in this

commubication, were obtained using the Ansoft HFSS

software, which uses the finite element method.

3.3. Radiation pattern

Fig.5 and Fig.6 illustrate co- polar radiation patterns

for the antenna. These radiation patterns were taken at

frequencies 5.5GHz and 8GHz. The patterns obtained

are typical of those for a monopole ( i.e,omni-

directional in azimuth and a figure of eight in the

elevation plane). The radiation patterns are consistent

over the frequency range of interest and there are good

simulation results.

Fig.8 shows simulated peak gain of the antenna. It has

a good gain except in the notched band. As desired,

one sharp gain decrease in the vicinity of 5.1GHz.

4. CONCLUSION

A novel compact microstrip fed printed monopole

antenna with single band notched characteristics, used

for various UWB applications has been presented. The

antenna consists of an UWB disk monopole which

provides the ground plane for a microstrip open – loop

resonator. The proposed antenna achieves a -10 dB

return loss , which is intterupted only by a notch-band

at 5.1GHz

The simulated results shows that the realized antenna

with a very compact size and relatively good radiation

characteristics from 3 to 11 GHz with one contrllable

notched band at 5.1 GHz.

REFERENCES

[1] X. Li and S.Hagness, “A confocal microwave

imaging algorithm for breast cancer detection,” IEEE

Microwave Wireless Comp.Lett,vol.11, no.3,pp.130-

132,Mar.2001.

[2] Y. Jang, H. Park, S. Jung, and J. Choi, “A compact

band-selective filter and antenna for UWB

application,” PIERS, vol.3, no.7, 2007.

[3] W. Hong, Y. Zhang, C. Yu, Z. Kuai, J. Zjou, and Z.

Wang etal., “compact ultra wideband antennawith

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[4] A. Abbosh, “Planar ultra wideband antennas with

rejected sub bands,” in Proc. Asia-Pacific Microwave

Conf., Bangkok, Thailand, 2007, pp.1-4.

[5] A. Kerkhoff and H. Ling, “ A parametric study of

band notched UWB planar monopole antennas,” in

3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00Freq [GHz]

-7.50

-5.00

-2.50

0.00

2.50

5.00

7.50

10.00

12.50

15.00

dB

(P

ea

kR

ea

lize

dG

ain

)


Curve Info

dB(PeakRealizedGain)Setup2 : Sw eepPhi='0deg' Theta='0deg'



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Proc. Antennas and propogation society Int. Symp,

Sendai, Japan, 2004, vol. 2, pp, 1768-1771.

[6] K. Bahadori and Y. Rahmat- Samii, “ A

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[7] S. Khan, J. Xiong, and S. He, “ Low profile

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[8] T.-P. vuong, A. Ghiotto Y. Duroc, and S.

tedjini, “ Design and characteristics of a small u-

slotted planar antenna for IR- UWB,” Wiley

MIcrow, Opt. Tech. Lett, vol. 49, no.7, pp. 1727-

1731, Apr. 2007.


Notch band antenna with integrated microstrip open loop resonator for UWB application

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