Loughborough University
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High gain cavity backed
UWB antenna with and
without band notch feature
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by the/an author.
Citation: AWAN, D., BASHIR, S. and WHITTOW, W.G., 2013. High gain
cavity backed UWB antenna with and without band notch feature. . 2013
Loughborough Antennas & Propagation Conference (LAPC), 11th-12th Novem-
ber 2013, Loughborough University, pp. 299-302
Additional Information:
• This is a conference paper.
Metadata Record: https://dspace.lboro.ac.uk/2134/14385
Version: Accepted for publication
Publisher: c
IEEE
Please cite the published version.
2013 Loughborough Antennas & Propagation Conference 11-12 November 2013, Loughborough, UK
High Gain Cavity Backed UWB Antenna with and
Without Band Notch Feature
Dawar Awan1, Shahid Bashir2, and William Whittow3
1
Dept. of Electrical Engineering, CECOS University of IT and Emerging Sciences, Peshawar, Pakistan
2
Dept. of Electrical Engineering, University of Engineering and Technology, Peshawar, Pakistan
3
School of Electronic, Electrical and Systems Engineering, Loughborough University, Leicestershire, UK
dawar09@yahoo.com; shahidbashir@nwfpuet.edu.pk; w.g.whittow@lboro.ac.uk
Abstract— High directivity antennas are often used in S11 plots for this antenna are shown in Fig. 4a and 5b
communication systems to meet specific coverage requirements. respectively. To increase the gain of the antenna, reflectors
This paper presents a unidirectional, high gain UWB antenna. A were placed on all sides except the front side of antenna. This
reference UWB antenna is considered and a metallic cavity is arrangement formed a box shaped cavity around the antenna.
built around it, this arrangement along with a stacked parasitic The resulting structure is shown in Fig. 2a. The gain and S11
patch shows a maximum increase of 8.5 dB in the gain of the plots for this antenna are shown in Fig. 4a and 5b respectively.
UWB antenna. A maximum increase of 8.43 dB in the gain is seen By placing a parasitic patch above the radiating patch in
for the UWB antenna having band rejection feature. stacked formation, the gain is seen to increase slightly. The
details of the resulting structure can be seen in Fig. 2b.
Keywords—Ultra-wide band; Band Notch; Cavity
The band rejection is achieved by making identical U-
I. INTRODUCTION shaped slots on the radiating and parasitic patch, as shown in
Fig. 1c. The gain and S11 plots for various configurations of
In the recent years UWB systems have become very this antenna are shown in Fig. 4c and 5d respectively. Except
popular because of their high data rates. Accordingly, the the slots, all other dimensions are the same as that of the
UWB antennas have gained as much popularity and interest Cavity-backed UWB antenna with SPP.
from the researchers and designers. A variety of UWB antenna
designs have been proposed. To mitigate the interference of the 44
narrow band systems to the UWB systems, various UWB 7.8
antennas having band notch characteristic have also been 10.92
proposed, like [1-3]. 44
Some UWB systems like ground penetrating radar (GPR), 20.7 20
through wall radar and medical imaging systems require high
2.6
gain and high directivity UWB antennas. To meet this
requirement various UWB antenna designs and techniques (a) (b)
have been proposed. In this paper we have presented a cavity-
backed UWB antenna with and without band rejection
property. Further, it is shown that using stacked parasitic patch
(SPP) in a cavity-backed UWB antenna further enhances the
gain and directivity. Cavity-backed narrow band antennas have
been extensively reported [4-7], but the use of cavity for the
UWB antenna is very rare. This research shows a simple cavity
design to increase the gain of UWB antennas with and without
band notch property. Compared to some previously proposed (c)
cavity-backed antennas, like [8-10], this design is simple,
Fig. 1. (a) Front side of reference antenna (b) back side of reference antenna
provides high gain, relatively smaller in size, almost (c) reference antenna with slot in the patch [12] (units: mm)
unidirectional radiation pattern throughout the operating band
and can have band rejection property as well. All the
simulations are conducted using CST MWS 2010.
II. ANTENNA DESIGN AND CONFIGURATION
Fig. 1a and 1b shows the reference UWB antenna; this
antenna has an operating bandwidth of 3.1 GHz to 10.6 GHz
(FCC’s defined range for UWB systems [11]). The gain and
978-1-4799-0091-6/13/$31.00 ©2013 IEEE
(e) (f)
(a)
(g) (h)
Fig. 3. Far field radiation pattern of proposed antenna at (a) 3.1 GHz (b) 5
GHz (c) 7 GHz (d) 9 GHz. (e) far field radiation pattern of reference antenna
at 3.1 GHz (f) 5 GHz (g) 7 GHz and (h) 9 GHz.
III. RESULTS AND DISCUSSION
A simple cavity-backed UWB antenna has been proposed
in this research. The gain plots of the antenna show significant
(b) increase in the gain throughout the UWB range of frequencies,
Fig. 2. (a) Cavity backed UWB antenna simulation model (b) Block diagram as a result of cavity backing. A maximum of 10dB gain and a
for Cavity backed UWB antenna with SPP (units: mm) maximum increase of 8db have been achieved in this
configuration. The addition of SPP slightly increases the gain
to a maximum of 10.5dB, but the distance of SPP may be
varied to achieve higher gain. The use of cavity has incredibly
concentrated the radiations in the forward direction, hence
increasing the directivity of antenna. Throughout the operating
band the antenna radiates only in the forward direction as
shown in Fig. 3. A broadside UWB reference antenna has been
converted to an almost unidirectional antenna with high gain.
This technique when extended to UWB antenna having
band rejection property, showed similar results with the band
(a) (b) rejecting property preserved. The use of cavity raised the gain
to a maximum of 9.5 dB, while the addition of SPP increased
the gain up to a maximum of 10.2 dB as shown in Fig. 4c. The
sharp decrease in the gain of antenna shows the rejected band.
The rejected band of the cavity-backed antenna is slightly
wider than the reference antenna as seen in Fig. 4d, which can
be adjusted by changing the dimensions of the U-shaped slot.
IV. CONCLUSION
In this research a high gain and highly directional UWB
(c) (d) antenna based on the concept of cavity backing is proposed. It
is shown that SPP technique can also be used along with the
cavity, which further improves the antenna gain. The proposed
antenna radiates only in the forward direction throughout the
operating band (3.1 GHz to 10.6 GHz). This property makes it
a good candidate for use in GPR, through wall radars, medical
imaging systems and other systems requiring directional
antennas. Further, it is shown that the same technique works
equally well for the UWB antenna having band rejection
property.
(d)
Fig. 4. (a) Gain for different configurations of antenna (b) S11 for different
(a) configurations of antenna (c) Gain of different configurations of antenna with
Band notch (d) S11 of different configurations of antenna with band notch
REFERENCES
[1] J. Kim, C. S. Cho, and J. W. Lee, “5.2 GHz notched ultra-wideband
antenna using slot-type SRR,” in Electronics Lett., vol. 42, no. 6, pp.
315–316, 2006.
[2] K. Chung, S. Hong, and J. Choi, “Ultra-wide band printed monopole
antenna with band notch filters,” in IET Microw. Antennas Propag.,
vol.1, no. 2, pp. 518–522, 2007.
[3] O. Ahmed, A. Sebak, “A Printed Monopole Antenna with Two Steps
and a Circular Slot for UWB Applications,” in IEEE Antennas Wireless
Propag. Lett., vol. 7, pp. 411–413, 2008.
[4] P. K. Singhal and S. Banerjee, “A cavity backed rectangular patch
antenna,” in Proc. 6th Int. Sym. Antennas, Propag. EM Theory, 2003,
pp. 112–115.
(b) [5] J. K. Paek and H. J. Eom, “Cylindrical Cavity-Backed Antenna,” in
IEEE Antennas Propag. Lett., vol. 8, pp. 852–855, 2009.
[6] M. H. Awida, E. Elkhouly and Aly E. Fathy,“Low-Cost High-Efficiency
Substrate-Integrated Cavity-Backed Single Element Antenna,” in IEEE
Antennas Propag. Society Int. Symp., 2010, pp. 10–13.
[7] A. Nesic, I. Radnovic, and N. Vojnovic,“New Type of Cavity-Backed
Antenna with Circular Polarization,” in 10th Int. Conf. Telecomm.
modern satellite and cable Broadcasting services, 2011, pp. 407–410.
[8] Li, Mingjian, and Luk, K.,”A Differentially-fed Magneto-Electric
Dipole Antenna for UWB Applications,” in Asia-Pacific Microw. Conf.
Proc., 2011, pp.1953–1956.
[9] R.A Moddy and S.K Sharma,”Ultra-wide Bandwidth ( UWB ) Planar
Monopole Antenna Backed by Novel Pyramidal-Shaped Cavity
Providing Directional Radiation Patterns,” in IEEE Antennas Wireless
Propapg. Lett., 2011, pp.1469–1472.
[10] S. Qu, C. Chan, and Q. Xue, “Ultra-wide band composite cavity-backed
folded sectorial antenna with stable pattern and high gain” in IEEE
Trans. Antennas Propag., vol. 57, no. 8, pp. 2478–2483, 2009.
(c) [11] Federal Communications Commission, “First report and order, revision
of part 15 of the commission’s rule regarding ultra-wideband
transmission system FCC 02-48”. Apr. 22, 2002.
[12] J. R. Panda and R. S. Kshetrimayum, “A Planar Microstrip-Line Fed
Elliptical UWB 5.2 GHz / 5.8 GHz Notch Antenna with U-Shaped Slot,”
in Int. Conf. Computer and Comm., 2010, pp. 806-811.
