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Frequency Reconfigurable Triple Band-Notched

Ultra-Wideband Antenna with Compact Size

Article in Progress In Electromagnetics Research C April 2017

DOI: 10.2528/PIERC17021001

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Progress In Electromagnetics Research C, Vol. 73, 3746, 2017

Frequency Reconfigurable Triple Band-Notched Ultra-Wideband

Antenna with Compact Size

Wael A. E. Ali* and Rana M. A. Moniem

AbstractA compact planar recongurable triple band-notched UWB Microstrip antenna is proposed
in this paper for UWB applications. A band rejection at ITU 8-GHz is generated by inserting an inverted
U-shaped metallic strip at the slotted ground plane. Moreover, by cutting two slots on radiating patch,
the second rejection at 3.6 GHz for WiMAX and the third rejection at 5.5 GHz for WLAN application
are generated. Then, by embedding two (PIN) diodes along the patch slots, switchable dual or single
band-notched behavior is added to the antenna performance. The simulated and measured results
show that the antenna can operate in a wider bandwidth from 3.1 GHz to 11 GHz, and it has a good
omnidirectional radiation pattern with stable gain. Furthermore, the designed antenna has a simple
structure and compact size of 20 20 mm2 . The proposed antenna can use the full potential of UWB
frequency range with recongurable band-notched behavior at 3.6, 5.5, 8.1 GHz to avoid interference
with WiMAX, WLAN, ITU systems respectively.

1. INTRODUCTION

Microstrip antennas have been found in many applications of wireless communication systems because
of their attractive characteristics such as low prole, light weight, low cost and easy fabrication [14].
Nevertheless, the major problem faced by microstrip antenna is its narrow bandwidth [5]. So, there is
increased interest to improve the bandwidth by using dierent techniques in microstrip antenna such as
creating slots [6], using gap coupled [7, 8], using partial ground [9] and inserting spirals rings [10]. The
bandwidth of these microstrip antennas may reach more than 30%. To deal with the current and future
applications, a UWB antenna is required with good characteristics such as VSWR, radiation pattern
and gain [11, 12]. However, some applications, such as WLAN for IEEE 802.11a operating in (5.155.35)
and (5.7255.825) GHz bands, WIMAX operating in (3.33.6) GHz and (5.255.85) GHz bands, C-band
in (3.74.2) GHz and ITU in (8.0258.4) GHz, face interference problem because of the allocation of
FCC for UWB communications between (3.110.6) GHz [1315]. To avoid this interference, an antenna
with multiband rejections is required [16]. To utilize the full potential of UWB, switching between the
rejections can be the best solution [17, 18].
Hence, this paper presents a novel design of a triple band-notched UWB microstrip antenna with
switchable characteristics for the band notches. The patch geometry has two inverted U-shaped slots
with dierent dimensions which oer satisfactory notches at 3.6 GHz for WIMAX and 5.5 GHz for
WLAN. Moreover, a notch appears at 8 GHz by implementing inverted U-shape beside the partial
ground. Finally, two switches (PIN diodes), which are chosen with specic properties, are embedded
along the patch slots, and they can switch between the existence and non-existence of the dual band
notches operating at 3.6 and 5.5 GHz. The numerical simulations are done by using commercial software.
Good VSWR and radiation characteristics are obtained, and these characteristics are very desirable for
the current applications.
Received 10 February 2017, Accepted 28 March 2017, Scheduled 6 April 2017
* Corresponding author: Wael Abd Ellatif Ali (wael abd ellatif@yahoo.com).
The authors are with the Electronics and Communications Engineering Department, Arab Academy for Science, Technology &
Maritime Transport (AASTMT), Alexandria, Egypt.
38 Ali and Moniem

The paper is organized as follows. Section 2 presents the design procedures of the proposed
triple band-notched UWB antenna. In Section 3, the numerical and experimental results of the
optimized triple band-notches with/without the recongurable characteristics are introduced. Finally,
the conclusion, which summarizes the main contributions of this work, is presented in Section 4.

2. DESIGN PROCEDURES OF THE PROPOSED TRIPLE BAND-NOTCHED

ANTENNA

The proposed rectangular UWB antenna is mounted on an FR4-epoxy substrate with r = 4.4, thickness
0.8 mm and loss tangent 0.018. This microstrip antenna is directly fed by feed line of 50 . The
structure of the antenna is very simple as it is made of rectangular slotted ground in order to enhance
the impedance bandwidth. The conguration of the presented antenna model is based on improving
bandwidth performance of the microstrip antenna, because its major disadvantage is having very narrow
bandwidth. Hence, in order to improve the impedance bandwidth performance of the antenna, some
modications should occur at the design such as creating slots in the radiation patch or notches with
suitable dimensions on the metallic parts.
Two small slots have been etched in the feed line and a larger slot in the ground plane as shown in
Fig. 1(a) to cover the range of UWB communications. The rst case of the proposed antenna covers a
range of frequencies from 3.1 to 11 GHz as shown in Fig. 2. Then, according to the FCCs allocations
of UWB frequency range from 3.1 to 10.6 GHz, it will cause interference with the existing wireless
communication systems. So, to avoid this problem at certain frequency bands, some techniques are
used here. In the second case, a large inverted U-shaped slot is etched in the radiation patch as shown
in Fig. 1(b). This slot is directly responsible for notching a certain frequency which is for WIMAX
application at 3.6 GHz as shown in Fig. 2. Another smaller inverted U-shaped slot is etched in the
radiating patch as shown in Fig. 1(c). It can be noticed form Fig. 2 that the second slot is directly
responsible for presenting a notch at 5.5 GHz for WLAN application. These two etched slots act as
band-stop lters, and they have suitable dimensions. The two slots are presented in the fourth case to
achieve simultaneous band-notched characteristics at the two operating bands of WLAN and WiMAX
as shown in Fig. 1(d), and it results in two band rejections at 3.6 and 5.5 GHz as depicted in Fig. 2. The
last stage of implementing a metallic inverted U-shape in the slotted ground plane is shown in Fig. 1(e).
Also, this metallic part acts as a band-stop lter which is directly responsible for introducing notchat
8.1 GHz for ITU band. After embedding the third resonator in the ground plane of the proposed UWB
antenna, it can be observed from Fig. 2 that triple notches have been obtained in the three desired bands

(a) (b) (c) (d) (e)

Figure 1. The proposed UWB antenna design procedures. (a) Case I, (b) Case II, (c) Case III, (d)
Case IV, (e) Case V.
Progress In Electromagnetics Research C, Vol. 73, 2017 39

Figure 2. Simulated VSWR for dierent cases.

in order to mitigate the interference problem with WLAN and WiMAX and ITU systems simultaneously.
The concept of etching slots in the radiation patch to act as a band-stop lters is because the surface
current, which will take longer path, and its direction will be changed, ows along the radiation stub,
and it will act as 2 resonator at the notched frequencies, which disturbs the resonance response [19].
The dimensions of these band-notched lters are determined by using the rule based on the desired
notch frequency (fnotch ) as follows [20]:
g c
= (1)
2 2fnotch e
 0.5
r + 1 r 1 12h
e = + 1+ (2)
2 2 wf
where g is the guided wavelength, c the speed of light, r the relative permittivity of the substrate,
e the eective relative permittivity, h the substrate height, and wf the width of the feed line.

3. RESULTS AND DISCUSSION

The proposed rectangular slotted microstrip antenna is printed on a low cost FR4-epoxy substrate with
compact dimensions of 2 2 cm2 . Fig. 3 shows the top and bottom views of the proposed triple band-
notched UWB antenna with detailed parameters. The optimized parameters of the proposed antenna
are listed in Table 1. In this section, the simulated and measured results of voltage standing wave ratio

(a) (b)
Figure 3. Detailed geometry of triple band-notched UWB antenna. (a) Top view. (b) Bottom view.
40 Ali and Moniem

Table 1. Optimized parameters of the UWB antenna.

Parameter Length (mm) Parameter Length (mm)

Ws 20 W11 9
Wg 19 W12 2.1
W1 9 Ls 20
W2 8 Lg 12
W3 7 L1 5.55
W4 6 L2 4.65
W5 5.2 L3 4.35
W6 3.6 L4 5.3
W7 2.8 L5 5.8
W8 0.2 L6 7.7
W9 0.8 L7 1.5
W10 1.5 L8 5.4

(a) (b)

Figure 4. Geometry of antenna with PIN diodes. (a) Top view. (b) Bottom view.

(VSWR), return loss (S11 ), current distribution and radiation patterns are presented and discussed. The
performance of proposed antenna is veried by simulating it using high frequency structure simulator
(HFSS 13) software tool [21].
Finally, in order to switch between the band notches and to achieve a recongurable structure, two
PIN diodes are embedded along the large and small slots on the radiating patch as shown in Fig. 4.
Since D1 is mounted along the large slot responsible for the WiMAX frequency at 3.6 GHz, and D2 is
mounted along the small slot responsible for the WLAN frequency at 5.5 GHz, there are four states of
switching can be shown in Table 2, and the simulated VSWR curves is shown in Fig. 5. Good agreement
between the desired VSWR behaviours and the data listed in Table 2 can be noticed, conrming the
ability of the proposed antenna to be recongurable between dierent band notches eciently.
The proposed triple band-notched antenna is fabricated as shown in Fig. 6 on a low cost FR4
substrate, then the measured VSWR is compared with the simulated ones. The two curves are typically
similar to each other since the three notches are centered at 3.6, 5.5, 8.1 GHz for both cases as shown
in Fig. 7. A comparison between simulated and measured results of the proposed triple band-notched
UWB antenna is presented in Table 3. The fabricated model covers a range of frequencies from 3.1
to 11 GHz, which makes this model suitable for UWB applications. After these good results, two PIN
diodes are embedded along the antenna slots to achieve the recongurability between band notches for
the proposed model as shown in Fig. 8.
Progress In Electromagnetics Research C, Vol. 73, 2017 41

Table 2. Dierent states of PIN diodes.

State D1 D2 Notches
1 OFF OFF 3.65.58.1 GHz
2 ON OFF 5.58.1 GHz
3 OFF ON 3.68.1 GHz
4 ON ON 8.1 GHz

Table 3. Simulation and measurement comparison of the proposed UWB antenna.

Simulation Measurement
Frequency range (GHz) 2.710.6 3.110.8
Notched frequencies (GHz) 3.6 5.5 8.1 3.6 5.5 8.15
Notched bands (GHz) 3.423.73 5.355.67 8.018.4 3.523.7 5.335.65 8.038.33

(a) (b)

Figure 5. Simulated VSWR for dierent states Figure 6. Prototype of the fabricated triple
of PIN diodes. band-rejected UWB antenna. (a) Front view. (b)
Rear view.

(a) (b)

Figure 7. VSWR characteristics of the proposed Figure 8. Prototype of the fabricated recong-
band-rejected antenna. urable triple band-rejected UWB antenna. (a)
Front view. (b) Rear view.

Then, by comparing the simulated VSWR and S11 curves with the measured ones as shown in
Fig. 9 and Fig. 10, respectively, it can be noticed that simulated and measured results are almost the
same when all switches are in the ON and OFF states. Moreover, the VSWR curve has three
notches at 3.6, 5.5 and 8.1 GHz with values greater than 2, which means that the three stopbands are
42 Ali and Moniem

Figure 9. VSWR comparison between simulated Figure 10. Return loss comparison between
and fabricated results. simulated and fabricated results.

active when all switches are OFF. After switching ON the two PIN diodes, the two notches at 3.6
and 5.5 GHz become below 2, which means that the stopbands are not activated at the operating bands
of WLAN and WiMAX as shown in Fig. 9. From S11 curves shown in Fig. 10, it can be observed that
all notches have above 10 dB return loss when all switches are OFF for both cases of simulation
and measurement, which means that the desired bands are rejected. Also, when all switches are ON,
the two notches at 3.6, and 5.5 GHz are below 10 dB, which conrms that the two band-stop lters
etched on the patch are idle.
To study the eect of the two dierent slots etched in the radiating patch and the eect of the
metallic part, which is implemented in the ground plane on the performance of proposed UWB antenna,
Fig. 11 explains the surface current distributions along the band-notched resonators at their respective
resonance frequencies.
Figure 11(a) shows the current distribution at 3.6 GHz, which is mainly concentrated at the large
slot, while the current is shown concentrated in Fig. 11(b) at the small slot which is responsible for band-
notched function at 5.5 GHz. Furthermore, the current is distributed along the metallic resonator on the
ground plane when the antenna is excited with f = 8.1 GHz as shown in Fig. 11(c). The concentration
of current along the three resonators as in Fig. 11 conrms the ability of the proposed UWB antenna
to provide band-stop behaviour at the three desired frequency bands of WiMAX, WLAN, and ITU
applications, and it cannot radiate at these three bands.
Figure 12 shows the simulated far-eld radiation patterns of the proposed antenna in the three
dierent planes, x-z, y-z and x-y planes. These planes reveal the radiation characteristics of the proposed
antenna at two dierent frequencies in the passband (3 and 7.5 GHz). The lower and higher resonance
frequencies have bi-directional radiation patterns at x-z and x-y planes and omnidirectional radiation
pattern at y-z plane, which are preferred and highly recommended for various wireless communication
applications.
The simulated realized gain of the proposed triple band-notched UWB antenna is illustrated in
Fig. 13. The average simulated realized gain of the recongurable UWB antenna is around 2.8 dBi over
the achieved frequency band, except the three notched frequency bands (3.6, 5.5, 8.1 GHz) with values
equal to 4.8 dBi, 3.7 dBi and 1.1 dBi, respectively. As can be depicted from Fig. 13, the realized
gain response validates the triple band-notched behaviour of the proposed UWB recongurable antenna,
which makes it applicable to UWB applications with high immunity from electromagnetic interference
attributed to wireless communication systems allocated in the UWB spectrum.
Table 4 introduces a performance comparison between the proposed work and other similar
relatively recent works in terms of the size, relative permittivity and thickness of substrate, and the
bandwidth of each notch with its respective resonance frequency. It is demonstrated in Table 4 that
the proposed antenna has the same type of substrate but with a compact size of 2 2 cm2 , and the
triple notches cover the specic bandwidths of WiMAX, WLAN and ITU centred at 3.6, 5.5, 8.1 GHz,
respectively.
Progress In Electromagnetics Research C, Vol. 73, 2017 43

(a) (b)

(c)

Figure 11. Current distributions at the three notch frequencies. (a) f = 3.6 GHz. (b) f = 5.5 GHz.
(c) f = 8.1 GHz.

0 0 0
-30 30 -30 30 -30 30
-10.00 -10.00 -10.00

-20.00 -20.00 -20.00

-60 60 -60 60 -60 60
-30.00 -30.00 -30.00

-40.00 -40.00 -40.00

-90 90 -90 90 -90 90

-120 120 -120 120 -120 120

-150 150 -150 150 -150 150

-180 -180 -180
(a) (b) (c)
f = 3 GHz f = 7.5 GHz

Figure 12. Normalized 2-D radiation patterns of the proposed antenna at two dierent frequencies.
(a) x-z plane. (b) y-z plane. (c) x-y plane.
44 Ali and Moniem

5
4
3

Realized Gain [dBi]

2
1
0
-1
-2
-3
-4
-5
2 3 4 5 6 7 8 9 10 11
Frequency [GHz]

Figure 13. The simulated realized gain of the optimized structure against frequency.

Table 4. Comparison between dierent triple band-notched designs.

Ref Size (cm2 ) Substrate Notches (GHz) 1st band 2nd band 3rd band
FR4 1.62.66 GHz 34 GHz 5.136.03 GHz
[22] 44 2.2, 3.54, 5.68
(r = 4.4) (48.18%) (28.24%) (15.8%)
FR4 3.33.7 GHz 5.155.35 GHz 7.257.75 GHz
[23] 2.8 3.2 3.6, 5.2, 7.3
(r = 4.4) (11.11%) (3.84%) (6.84%)
FR4 3.43.7 GHz 5.335.67 GHz 8.018.35 GHz
proposed 22 3.6, 5.5, 8.1
(r = 4.4) (8.3%) (6.2%) (4.2%)

4. CONCLUSION

In this paper, a compact triple band rejected microstrip antenna with recongurable single/dual band
notches is proposed for operation in UWB applications. The proposed antenna is printed on a low
cost FR4-epoxy substrate with dimensions of 2 2 cm2 , and a larger impedance bandwidth from
3.1 to 11 GHz has been achieved except triple notches at 3.6, 5.5, 8.1 GHz for interference mitigation
purpose with WiMAX, WLAN, ITU systems. The band-notched behaviour of each slot in the radiating
patch is recongured electronically by using PIN diode integrated within the antenna to suppress the
unwanted interfering signals. By changing the states of the switches, the antenna can switch between
various frequency responses. Good consistency can be observed between measured and simulated
impedance characteristics, which demonstrates that the proposed antenna can be utilized for various
UWB applications that are immune to interferences from neighbouring RF systems. Moreover, the
proposed antenna has an omnidirectional radiation pattern, and the realized gain is almost stable over
the entire bandwidth with sharp notches.

ACKNOWLEDGMENT

The author would like to thank Dr. Hesham Mohamed and Prof. Dr. EsmatAbdallah for fabricating the
proposed antenna in National Research Center (NRC) in Egypt. Also, thanks goes to Eng. Nagah for
embedding the PIN diodes on the fabricated prototype in Banha Company for Electronic Industries in
Egypt.

REFERENCES

1. Ali, W. A., A. I. Zaki, and M. H. Abdou, Design and fabrication of rectangular ring monopole array
with parasitic elements for UWB applications, Microw. Opt. Technol. Lett., Vol. 58, 22682273,
2016.
Progress In Electromagnetics Research C, Vol. 73, 2017 45

2. Boutejdar, A. and W. Abd Ellatif, A novel compact UWB monopole antenna with enhanced
bandwidth using triangular defected microstrip structure and stepped cut technique, Microw.
Opt. Technol. Lett., Vol. 58, 15141519, 2016.
3. Gao, F., F. Zhang, L. Lu, T. Ni, and Y. Jiao, Low-prole dipole antenna with enhanced
impedance and gain performance for wideband wireless applications, IEEE Antennas and Wireless
Propagation Letters, Vol. 12, 372375, 2013.
4. Ghaderi, M. R. and F. Mohajeri, A compact hexagonal wide-slot antenna with microstrip-fed
monopole for UWB application, IEEE Antennas and Wireless Propagation Letters, Vol. 10, 682
685, 2011.
5. Ren, X., X. Chen, Y. Liu, W. Jin, and K. Huang, A stacked microstrip antenna array with
fractal patches, International Journal of Antennas and Propagation, Vol. 2014, 10 pages, Article
ID 542953, 2014.
6. Azim, R. and M. T. Islam, Printed Wide Slot Ultra-wideband Antenna, Advancement in Microstrip
Antennas with Recent Applications, Prof. Ahmed Kishk, (Ed.), InTech, 2013, DOI: 10.5772/51961.
7. Kumar, P. and G. Singh, Gap-coupling: A potential method for enhancing the bandwidth of
microstrip antennas, Advanced Computational Techniques in Electromagnetics, Vol. 2012, 16,
2012.
8. Nirate, S., R. M. Yadahalli, K. K. Usha, R. M. Vani, and P. V. Hunagund, Wideband gap-
coupled suspended rectangular microstrip antenna, International Conference on Recent Advances
in Microwave Theory and Applications, 2008, MICROWAVE 2008, 833835, Jaipur, 2008.
9. Mewara, H. S., M. M. Sharma, M. Sharma, and A. Dadhich, A novel ultra-wide band antenna
design using notches, stepped microstrip feed and beveled partial ground with beveled parasitic
strip, 2013 IEEE Applied Electromagnetics Conference (AEMC), 12, Bhubaneswar, 2013.
10. Sun, L., M. He, J. Hu, Y. Zhu, and H. Chen, A Buttery-shaped wideband microstrip
patch antenna for wireless communication, International Journal of Antennas and Propagation,
Vol. 2015, 8 Pages, Article ID 328208, 2015.
11. Osama, H. and A.-R. Sebak, UWB Antennas for Wireless Applications, INTECH Open Access
Publisher, 2013.
12. Liu, J., S. Zhong, and K. P. Esselle, A printed elliptical monopole antenna with modied feeding
structure for bandwidth enhancement, IEEE Transactions on Antennas and Propagation, Vol. 59,
No. 2, 667670, Feb. 2011.
13. Li, L., Z. L. Zhou, and J. S. Hong, Compact UWB antenna with four band-notches for UWB
applications, Electronics Letters, Vol. 47, No. 22, 12111212, Oct. 27, 2011.
14. Abdollahvand, M., G. Dadashzadeh, and D. Mostafa, Compact dual band-notched printed
monopole antenna for UWB application, IEEE Antennas and Wireless Propagation Letters, Vol. 9,
11481151, 2010.
15. Zhu, F. G., S. Gao, A. T. Ho, R. A. Abd-Alhameed, C. H. See, T. W. C. Brown, J. Z. Li, G. Wei,
and J. D. Xu, Multiple band-notched UWB antenna with band-rejection elements integrated in the
feedline, IEEE Transactions on Antennas and Propagation, Vol. 61, No. 8, 39523960, Aug. 2013.
16. Ojaroudi, N., M. Ojaroudi, and N. Ghadimi, Dual band-notched small monopole antenna with
novel W-shaped conductor backed-plane and novel T-shaped slot for UWB applications, IET
Microwaves, Antennas & Propagation, Vol. 7, No. 1, 814, Jan. 2013.
17. Sarah, J., et al., UWB antenna with recongurable band-notched characteristics using ideal
switches, 2014 IEEE International Microwave and RF Conference (IMaRC), IEEE, 2014.
18. Ojaroudi, N., N. Ghadimi, Y. Ojaroudi, and S. Ojaroudi, A novel design of microstrip antenna
with recongurable band rejection for cognitive radio applications, Microw. Opt. Technol. Lett.,
Vol. 56, 29983003, 2014.
19. Mohammad, O., N. Ojaroudi, and N. Ghadimi, A simple design of UWB small microstrip slot
antenna with band-notched performance by using a T-shaped slit and a pair of U-shaped conductor-
backed plane, Applied Computational Electromagnetics Society Journal, Vol. 28, No. 8, 701706,
2013.
 46 Ali and Moniem

20. Sarkar, D., K. V. Srivastava, and K. Saurav, A compact microstrip-fed triple band-notched UWB
monopole antenna, IEEE Antennas and Wireless Propagation Letters, Vol. 13, 396399, 2014.
21. Ansoft High Frequency Structure Simulator (HFSS), Ver. 13, Ansoft Corporation, 2010.
22. Abdelhalim, C. and D. Farid, A compact planar UWB antenna with triple controllable band-
notched characteristics, International Journal of Antennas and Propagation, Vol. 2014, 10 pages,
Article ID 848062, 2014.
23. Wang, Q. and Y. Zhang, Design of a compact UWB antenna with triple band-notched
characteristics, International Journal of Antennas and Propagation, Vol. 2014, 9 pages, Article ID
892765, 2014.

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