Abstract
A coplanar waveguide (CPW)fed patch antenna with triple wideband is presented for simultaneously satisfying Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) applications. The proposed antenna mainly consists by three radiating elements: inverted Lshaped Stub1, inverted Lshaped Stub2, and a rectangle Stub3 with a defected ground structure for band broadening. By adjusting the lengths of the three Stubs, three resonant frequencies can be achieved and adjusted separately. The proposed antenna with overall size of only 20×37mm^{2} explores good triple wideband operation with −10 dB impedance bandwidths of 25.70%, 45.63% and 50.10% at 2.47, 3.20, and 4.92 GHz, respectively, covering the 2.4/5.2/5.8 GHz WLAN and 2.5/3.5/5.5 GHz WiMAX operation bandwidths. This design gives suitable results with a reduction in size and weight and allows integration in handheld devices. Furthermore, nearly omnidirectional radiation patterns over the operating bands have been obtained.
Coplanar waveguide (CPW) feed; Defected ground structure (DGS); Patch antenna; Tripleband antenna; Wideband antenna; WLAN/WiMAX applications
I. INTRODUCTION
In modern wireless communication systems, multiband antenna plays a very important role for wireless service requirements [^{1}1 J. Anguera, A. Andújar, M.C. Huynh, C. Orlenius, C. Picher, and C. Puente, Advances in Antenna Technology for Wireless Handheld Devices, International Journal on Antennas and Propagation, Volume 2013. Article ID 838364., ^{2}2 K.L. Wong, Planar Antennas for Wireless Communications, Wiley InterScience 2003.]. Wireless Local Area Network (WLAN) standards of 2.4002.484 GHz (IEEE 802.11b / g) / 5.155.35 GHz / 5.7255.825 GHz (IEEE 802.11a) and Worldwide Interoperability for Microwave Access (WiMAX) standards of 2.52.69 GHz / 3.43.69 GHz / 5.255.85 GHz are extensively applied in mobile devices such as handheld computers and intelligent phones (4G smartphones). Many researchers pay lots of attention to designing antennas covering all frequency bands with characteristics of simple multiband, lowprofile, compact size and omnidirectional pattern for multiservice systems, especially for WLAN and WiMAX applications in wireless communication systems [^{3}3 S. S. Huang, J. Li, and J. Z. Zhao, A Novel Compact Planar TripleBand Monopole Antenna for WLAN/WiMAX Applications, Progress in Electromagnetics Research Letters, Vol. 50, pp. 117123, 2014.]. Furthermore, it is desirable to be able to control the antenna bandwidth over different frequency bands individually [^{4}4 A. Mehdipour, A.R. Sebak, C. W. Trueman, and T. A. Denidni, Compact Multiband Planar Antenna for 2.4/3.5/5.2/5.8GHz Wireless Applications, IEEE Antennas Wireless Propag Lett, Vol. 11, pp.144147, 2012., ^{5}5 L. Xu, Z. Y. Xin, and J. He,A Compact TripleBand ForkShaped Antenna for WLAN/WiMAX Applications, Progress in Electromagnetics Research Letters, Vol. 40, pp. 6169, 2013.].
There are various reported antenna designs for wireless systems, but the most are singleband or dualband [^{6}6 W.C. Liua, C.M.Wua, and N.C.Chub, A compact lowprofile dualband antenna for WLAN and WAVE applications, Int. J. Electron. Commun. (AEÜ), Vol. 66, Issue. 6, pp. 467471, 2012.
7 C. M. Wu, Wideband dualfrequency CPWfed triangular monopole antenna for DCS/WLAN application,Int. J. Electron. Commun. (AEÜ), Vol. 61, pp. 563567, 2007.
8 M. NaserMoghadasi, A. Danideh, A. Bakhtiari, and R. Sadeghifakhr, Compact Slot Antenna for MIMO Applications in the WLAN Bands, Microwave and Optical Technology Letters, Vol. 55, pp. 24902493, 2013.
9 W.C. Liu, C.M. Wu and N.C. Chu , ACompact CPWFed Slotted Patch Antenna for DualBand Operation, IEEE Antennas Wireless Propag Lett, Vol. 9, pp. 110113, 2010.
10 T. L. Zhang, Z. H. Yan, L. Chen, and Y. Song, A Compact DualBand CPWfed Planar Monopole Antenna for WLAN Applications, J. of Electromagn.Waves and Appl, vol. 22, pp. 20972104, 2008.
11 J. Kaur, R. Khanna, and M.A. Kartikeyan, Novel DualBand Multistrip Monopole Antenna with Defected Ground Structure for WLAN/IMT/BLUETOOTH/WiMAX Applications,International Journal of Microwave and Wireless Technologies, Vol. 6, Special Issue 01, pp. 93100, Feb. 2014.
12 Y. Zhuo, L. Yan, X. Zhao, and K. Huang, A Compact DualBand Patch Antenna for WLAN applications, Progress in Electromagnetics Research Letters, Vol. 26, pp. 153160, 2011.
13 J. H. Yoon, Fabrication and Measurement of Rectangular Ring with Openended CPWFed Monopole Antenna for 2.4/5.2GHz WLAN Operation, Microwave and Optical Technology Letters, Vol. 48, no. 8, pp. 14801483, Aug. 2006.
14 S. Gai, Y.C. Jiao, Y.B. Yang, C.Y. Li and J.G. Gong, Design of a Novel MicrostripFed DualBand Slot Antenna for WLAN Applications, Progress in Electromagnetics Research Letters, Vol. 13, pp. 7581, 2010.
15 L. Peng and C.L. Ruan, A Microstrip Fed Monopole Patch Antenna with three Stubs for Dualband WLAN Applications, J. of Electromagn.Waves and Appl, Vol. 21, no. 15, pp. 23592369, 2007.
16 D.Parkash, R. Khanna, Design of a Dual Band Monopole Antenna for WLAN/WiMAX Applications, in Proc. 7th WOCN, Sep. 68, 2010.
17 L. Zhang, Y. C. Jiao, G. Zhao, Y. Song, and F. S. Zhang, Broadband DualBand CPWFed Closed Rectangular Ring Monopole Antenna with A Vertical Strip for WLAN Operation, Microwave and Optical Technology Letters, Vol. 50, no. 7, pp. 19291930, Jul. 2008.^{18}18 R. Dakir, J. Zbitou, A. Mouhsen, A. Tribak, A. Sanchez and M. Latrach,New LowCost Broadband CPWFed Planar Antenna, International Journal of Microwave and Wireless Technologies, Research Paper, 6 pages, 11 Dec. 2014.]. A microstrip fed monopole patch antenna with three stubs for dualband WLAN applications is depicted in [^{15}15 L. Peng and C.L. Ruan, A Microstrip Fed Monopole Patch Antenna with three Stubs for Dualband WLAN Applications, J. of Electromagn.Waves and Appl, Vol. 21, no. 15, pp. 23592369, 2007.]. In [^{19}19 J. Pei, A. G. Wang, S. Gao, and W. Leng, Miniaturized TripleBand Antenna with a Defected Ground Plane for WLAN/WiMAX Applications,IEEE Antennas Wireless Propag Lett, Vol. 10, pp. 298301, 2011.], a simple miniaturized tripleband antenna is realized by using a defected ground plane for WLAN/WiMAX applications. Double Lslot microstrip patch antenna array for WiMAX and WLAN applications is proposed in [^{20}20 R. Jothi Chitra, V. Nagarajan, Double Lslot Microstrip Patch Antenna Array for WiMAX and WLAN Applications, Computers and Electrical Engineering, Vol. 39, pp. 10261041, 2013.]. A coplanar waveguide (CPW)fed planar monopole antenna with Yshaped for PCS / WLAN applications and a compact dualband planar antenna for DCS1900 / PCS / PHS, WCDMA / IMT2000 and WLAN applications are presented in [^{21}21 W.C. Liu and C.F. Hsu, DualBand CPWFed YShaped Monopole Antenna for PCS/WLAN Application, Electronics Letters, Vol. 41, no. 7, pp. 390391, Mar. 2005., ^{22}22 G. Augustin, P. C. Bybi, V. P. Sarin, P. Mohanan, C. K. Aanandan, and K. Vasudevan, A Compact DualBand Planar Antenna for DCS1900/PCS/PHS, WCDMA/IMT2000, and WLAN Applications, IEEE Antennas Wireless Propag Lett, Vol. 7, pp. 108111, 2008.]. In [^{23}23 Q. Zhao, S. X. Gong, W. Jiang, B. Yang, and J. Xie, Compact WideSlot TriBand Antenna for WLAN/WIMAX Applications, Progress In Electromagnetics Research Letters, Vol. 18, pp. 918, 2010.], a compact antenna with a wide square slot in the center, a rectangular feeding strip and two pairs of planar inverted L strips connecting with the slotted ground for WLAN / WiMAX applications.
In [^{24}24 X.L. Sun, J. Zhang, S.W. Cheung, and T.I. Yuk, A Tripleband Monopole Antenna for WLAN and WiMAX Applications, in Proc. IEEE International Symposium (APSURSI), 814 Jul. 2012, pp.12.], a triple band monopole antenna for WLAN/WiMAX applications is obtained; the radiator of the antenna is designed on a 40(W) × 40(L) mm^{2} substrate and the radiator is composed of three elements, two branches and a short stub. In [^{25}25 L. Kang, Y.Z. Yin, H. Li, W.J. Huang and S.F. Zheng, DualWideband Symmetrical GShaped Slotted Monopole Antenna for WLAN/WIMAX Applications, Progress In Electromagnetics Research Letters, Vol. 17, pp. 5565, 2010.], a dualwideband symmetrical Gshaped slotted monopole antenna is designed for WLAN / WiMAX applications. In [^{26}26 W.C. Liu, Dual Wideband Coplanar WaveguideFed Notched Antennas with Asymmetrical Grounds for MultiBand Wireless Application, IET Microw. Antennas Propag, Vol. 1, no. 5, pp. 980985, Oct. 2007.], a dual wideband coplanar waveguidefed notched antenna with two asymmetrical ground planes for multiband wireless application has been reported. Further, in [^{27}27 C.Y. Pan, T.S. Horng, W.S. Chenand C.H. Huang, Dual Wideband Printed Monopole Antenna for WLAN/WiMAX Applications,IEEE Antennas Wireless Propag Lett, vol. 6, pp.149151, 2007.], a dual wideband printed monopole antenna has been designed to cover WLAN and WiMAX frequency bands. In [^{28}28 H. M. El Misilmani, M. AlHusseini, K. Y. Kabalan, and A. ElHajj, A Simple Miniaturized Tripleband Antenna for WLAN/WiMAX Applications, in PIERS Proceedings, Moscow, Russia, Aug. 1923, 2012, pp. 608612.], the rectangular patch is the main radiating element of the tripleband antenna combined with splitring slot enclosed inside of it for WLAN / WiMAX applications is presented. However, the aforementioned techniques supporting triple/multiband operations still suffer from large overall size or a complicated structure [^{29}29 Y. Song, Y.C. Jiao, G. Zhao, and F.S. Zhang, Multiband CPWFed TriangleShaped Monopole Antenna for Wireless Applications,Progress in Electromagnetics Research, PIER, Vol. 70, pp. 329336, 2007., ^{30}30 P. Liu, Y. Zou, B. Xie, X. Liu, and B. Sun, Compact CPWFed TriBand Printed Antenna With Meandering SplitRing Slot for WLAN/WiMAX Applications, IEEE Antennas Wireless Propag Lett, Vol. 11, pp.12421244, 2012.]. In [^{31}31 W. Hu, Y. Z. Yin, P. Fei, and X. Yang, Compact Tri band SquareSlot Antenna with Symmetrical LStrips for WLAN/WiMAX Applications, IEEE Antennas Wireless Propag Lett, vol. 10, pp.462465, 2011.], a squareslot antenna with symmetrical Lstrips is presented for WLAN and WiMAX applications, but the three resonant frequencies cannot be tuned independently.
In this paper, a simple miniaturized triple wideband patch antenna with a defected ground structure for WLAN and WiMAX applications is proposed, which is fed by a coplanar waveguide (CPW). The antenna is created by three Stubs and three resonant frequencies can be obtained and tuned individually. Simulated results show that the three operation bandwidths of the proposed antenna are 635 MHz, 1460 MHz and 2465 MHz, respectively, which satisfy the required bandwidth of the 2.4 / 5.2 / 5.8 GHz (WLAN) and 2.5 / 3.5 / 5.5 GHz (WiMAX) with an S_{11} less than 10 dB. Details of the antenna design and the effects of the key structure parameters on the antenna performances are neatly examined and discussed.
II. ANTENNA DESIGN
The geometry of the proposed tripleband antenna is illustrated in Fig. 1. The antenna substrate is a Rogers 4350 (thickness H = 0.508 mm, relative permittivity ε_{r} = 3.66 and dielectric loss tangent of 0.004). The dimension of the substrate is 20×37 mm^{2}.
In the geometry, the resonant path length L_{11} (L_{1} + W_{1} + G + Ls_{1}), L_{22} (L_{1} + W_{1} + G + Ls_{2}) and L_{33} (L_{1} + G + Ls_{3}) of the three Stubs are set close to quarterwavelength at their fundamental resonant frequencies and can be calculated from the following equations [^{32}32 Q.X. Chu and L.H. Ye, Design of Compact DualWideband Antenna with Assembled Monopoles, IEEE Transactions on Antennas and Propagation, vol. 58, no. 12, pp.40634066, Dec. 2010.]:
The effective permittivity is given approximately by [^{33}33 Yi Huang; Kevin Boyle.: Antennas from Theory to Practice, 2008 John Wiley & Sons Ltd.]:
where
Where c is the speed of light, W_{f}_{} is the conductor width, ε_{r} is the relative permittivity, H is the substrate thickness, ε_{eff} is the effective permittivity; f_{1}, f_{2} and f_{3} denote the fundamental resonant frequencies of the Stub1, Stub2 and Stub3 respectively. The planar antenna is fed by a 50Ω impedance CPW that has a central strip having as width W_{}_{f} = 1.55 mm and the gap between the central feed line and the ground is fixed at g = 0.3 mm. The proposed antenna was excited by a Wave Port with a width W_{CPW} = 10 mm and a height h_{CPW} = 5 mm. For detailed design, all parameters of the proposed antenna are optimized using the software package High Frequency Structure Simulator (HFSS^{®}) which is based on the Finite Element Method (FEM) and are shown in Table I.
The simulated reflection coefficient is presented for the optimized set of antenna parameters in Fig. 2. From the simulated result, it is apparent that a single antenna having three multiple resonant frequencies with a wide bandwidth is obtained. The simulated impedance bandwidths for S_{11}< −10 dB are about 635 MHz for the first band (2.085 GHz to 2.72 GHz), 1460 MHz for the second band (2.89 GHz to 4.35 GHz), and 2465 MHz for the third band (4.59 to 7.055 GHz). The proposed antenna has a broader bandwidth covering the required bandwidths of the IEEE 802.11 WLAN standards of 2.4 GHz (2.4  2.484 GHz), 5.2 GHz (5.15  5.35 GHz), and 5.8 GHz (5.725  5.825 GHz); WiMAX standards in the bands at 2.5 GHz (2.5  2.69 GHz), 3.5 GHz (3.4  3.69 GHz) and 5.5 GHz (5.25  5.85 GHz).
Table II shows the values of resonant frequencies and bandwidths at 10 dB of the three resonant modes. For the first resonant mode, the resonant frequency is about 2.47 GHz (S_{11} = 13.25 dB), the second resonant frequency for the second mode is about 3.20 GHz (S_{11} = 41.85 dB), and the third resonant frequency is about 4.92 GHz (S_{11} = 48.11 dB).
It is worth mentioning that the configuration of the ground plane also affects the characteristics of the antenna. In this design, the two symmetrical ground planes are defected for ameliorating the impedance performance and broadening the bandwidth especially for the second and the third operating bands. In fact, ground plane has been useful to design multiband handset antennas [^{34}34 A. Cabedo, J. Anguera, C. Picher, M. Ribó, and C. Puente, MultiBand Handset Antenna Combining a PIFA, Slots, and Ground Plane Modes, IEEE Transactions on Antennas and Propagation, vol.57, no. 9, pp. 25262533, Sep. 2003.
35 M.F. Abedin, and M. Ali, Modifying the Ground Plane and Its Effects on Planar InvertedF Antennas (PIFAs) for Mobile Phone Handsets, IEEE Antennas and Wireless Propagation Letters, vol.2, pp.226229, 2003 .^{36}36 J. Anguera, I. Sanz, J. Mumbrú, and C. Puente, MultiBand Handset Antenna with a Parallel Excitation of PIFA and Slot Radiators, IEEE Transactions on Antennas and Propagation, vol.58, no. 2, pp. 348356, Feb. 2010.].
III. PARAMETRIC STUDY
A. The Ls1 Variation Effects
The effects of the length of the first stub (Stub1) on the antenna performance are plotted in Fig. 3. This figure shows the simulated reflection coefficients when the length of Ls_{1} changes. By adjusting the length of Ls_{1}, the total length of Stub1 varies. It is seen that the increase in Ls_{1} decreases the resonant frequency of the first band and vice versa, while other resonant frequency bands are slightly affected.
B. The Ls2 Variation Effects
Fig. 4 shows the simulation of the reflection coefficients with variation of Ls_{2} (Stub2). By tuning the length of Ls_{2} from 9.5 mm to 12.5 mm, it is clear that the raise in Ls_{2} decreases the resonant frequency of the second band. The third band shifts to higher frequencies as Ls_{2} is increasing, which is possibly due to the changing coupling between the two inverted Lshaped. The first band is not affected.
C. The Ls3 Variation Effects
Varying the length Ls_{3} of Stub3 to be 8.5, 9.5, 10.5 and 11.5 mm, it can be seen from Fig. 5, Tables III and IV that with the increasing of length Ls_{3}, the third band shifts towards the lower frequency with the bandwidth increases slightly, while other resonant frequency bands have not been changed.
D. The Effects of the Defected Ground Structure (DGS) on the Antenna Performance
To demonstrate the effect of the square and rectangular truncation on the ground plane, Fig. 6(a) and Fig. 6(b) show the different evolution of the geometry of the two ground planes with and without truncation and its corresponding simulated reflection coefficients. We remark from Table V and Fig. 6(b) that the first truncation (P_{1}, P_{2}) influences on the impedance matching of the second band (WiMAX) and the reflection coefficient is enhanced from 21.5 dB to 37.24 dB. Furthermore, the second truncation (W_{2}, L_{2}) affects the upper band; the reflection coefficient is enhanced from 30.68 dB to 39.69 dB. For the proposed antenna, more amelioration of the reflection coefficient and the bandwidth were registered for second and third resonant band. The change of ground structure has small effects on the first band.
(a) Design evolution of the geometry of the two ground planes (b) Simulated reflection coefficients for different geometry of the two ground planes.
E. The Gap Variation Effects on the Impedance Matching Performance of the Antenna
An important feature of the proposed antenna is the capability of impedance matching at three operating frequencies using a single CPW feed line. For this, the coupling effect between the feed line and the two ground planes is investigated. Fig. 7 shows the simulated reflection coefficient for the proposed antenna with different gap width (g) of 0.1, 0.2, 0.3 and 0.35 mm. As seen in figures 7 and 8, the gap width has a significant effect on the impedance matching performance of the proposed antenna for the three resonant frequencies.
Real part and imaginary part of the impedance of the proposed antenna with various gap distance g.
The matching condition of the three bands is sensitive to the variation of g. The impedance matching condition for the three operating bands can be optimized with g equal to 0.3 mm.
F. The L1 Variation Effects
As shown in Fig. 9, L_{1} (the gap between the radiating patch and the two ground planes) could disturb the performance of the second and the third band antenna but the first band is not affected. It is evident that the reflection coefficient of the proposed antenna with L_{1} = 3.8 mm is better than that L_{1} = 4.3 mm and L_{1} = 4.8 mm.
IV. CURRENT DISTRIBUTIONS AND RADIATION PATTERNS
In order to better understand the antenna behavior, the current distributions of the threeband antenna at frequencies of 2.47 GHz, 3.20 GHz and 4.92 GHz are simulated and shown respectively in figures 10 (a), (b) and (c).
Simulated surface current distributions of the proposed antenna at frequencies (a) 2.47 GHz, (b) 3.20 GHz and (c) 4.92 GHz.
It can be evidently seen from Fig. 10 that the current distribution at the three resonant frequencies is different. Concerning the first resonant mode (2.47 GHz), a large surface of the current density is observed along the inverted Lshaped Stub1. Whereas for the second frequency band (3.20 GHz), the current distribution is mainly distributed along the inverted Lshaped Stub2, on the other hand for the third resonant mode (4.92 GHz), the current distribution becomes more concentrated along the Stub3. Nevertheless, they also have a common characteristic that is a large current is concentrated along the feed line.
The simulated radiation patterns of the proposed antenna are shown in figures 11(a), (b) and (c) at 2.47, 3.20, and 4.92 GHz, respectively. It can be obviously noticed that the nearly omnidirectional radiation in the Hplane (yzplane) and like a dipole radiation patterns (bidirectional) in the Eplane (xzplane) are obtained at these frequencies.
Simulated radiation pattern of the proposed antenna at different frequencies (a) 2.47 GHz, (b) 3.20 GHz, and (c) 4.92 GHz.
The simulated antenna gain against frequency for the proposed antenna across the three bands is shown in Fig. 12. First over the 2.4 GHz operation band (2.085  2.72 GHz); the simulated gain is varied from 2.4 dBi to 0.08 dBi. Then for the medium band (2.89  4.35 GHz), the simulated antenna gain is about 1.27 dBi to 2.62 dBi. Finally at the higher band (4.59  7.055 GHz), the simulated gain of the antenna changes from 1.05 dBi to 4.39 dBi.
V. CONCLUSION
A simple miniaturized triple wideband CPWfed patch antenna with a defected ground structure was proposed with its parametric study. The substrate size of the proposed antenna is 20×37mm^{2} with a thickness of 0.508 mm. The simulated result shows that the impedance bandwidths are from 2.085 to 2.72 GHz, 2.89 to 4.35 GHz and 4.59 to 7.055 GHz, covering all the 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands by using two separate resonant inverted Lshaped Stubs (Stub1 and Stub2) and a rectangle Stub3. The three resonant frequencies of the proposed antenna can be tuned individually by adjusting the length of the three Stubs. Accordingly, the proposed antenna is expected to be a good candidate for WLAN/WiMAX wireless communication systems.
ACKNOWLEDGMENT
This work is supported by the National Center for Scientific and Technical Research.
REFERENCES

^{1}J. Anguera, A. Andújar, M.C. Huynh, C. Orlenius, C. Picher, and C. Puente, Advances in Antenna Technology for Wireless Handheld Devices, International Journal on Antennas and Propagation, Volume 2013. Article ID 838364.

^{2}K.L. Wong, Planar Antennas for Wireless Communications, Wiley InterScience 2003.

^{3}S. S. Huang, J. Li, and J. Z. Zhao, A Novel Compact Planar TripleBand Monopole Antenna for WLAN/WiMAX Applications, Progress in Electromagnetics Research Letters, Vol. 50, pp. 117123, 2014.

^{4}A. Mehdipour, A.R. Sebak, C. W. Trueman, and T. A. Denidni, Compact Multiband Planar Antenna for 2.4/3.5/5.2/5.8GHz Wireless Applications, IEEE Antennas Wireless Propag Lett, Vol. 11, pp.144147, 2012.

^{5}L. Xu, Z. Y. Xin, and J. He,A Compact TripleBand ForkShaped Antenna for WLAN/WiMAX Applications, Progress in Electromagnetics Research Letters, Vol. 40, pp. 6169, 2013.

^{6}W.C. Liua, C.M.Wua, and N.C.Chub, A compact lowprofile dualband antenna for WLAN and WAVE applications, Int. J. Electron. Commun. (AEÜ), Vol. 66, Issue. 6, pp. 467471, 2012.

^{7}C. M. Wu, Wideband dualfrequency CPWfed triangular monopole antenna for DCS/WLAN application,Int. J. Electron. Commun. (AEÜ), Vol. 61, pp. 563567, 2007.

^{8}M. NaserMoghadasi, A. Danideh, A. Bakhtiari, and R. Sadeghifakhr, Compact Slot Antenna for MIMO Applications in the WLAN Bands, Microwave and Optical Technology Letters, Vol. 55, pp. 24902493, 2013.

^{9}W.C. Liu, C.M. Wu and N.C. Chu , ACompact CPWFed Slotted Patch Antenna for DualBand Operation, IEEE Antennas Wireless Propag Lett, Vol. 9, pp. 110113, 2010.

^{10}T. L. Zhang, Z. H. Yan, L. Chen, and Y. Song, A Compact DualBand CPWfed Planar Monopole Antenna for WLAN Applications, J. of Electromagn.Waves and Appl, vol. 22, pp. 20972104, 2008.

^{11}J. Kaur, R. Khanna, and M.A. Kartikeyan, Novel DualBand Multistrip Monopole Antenna with Defected Ground Structure for WLAN/IMT/BLUETOOTH/WiMAX Applications,International Journal of Microwave and Wireless Technologies, Vol. 6, Special Issue 01, pp. 93100, Feb. 2014.

^{12}Y. Zhuo, L. Yan, X. Zhao, and K. Huang, A Compact DualBand Patch Antenna for WLAN applications, Progress in Electromagnetics Research Letters, Vol. 26, pp. 153160, 2011.

^{13}J. H. Yoon, Fabrication and Measurement of Rectangular Ring with Openended CPWFed Monopole Antenna for 2.4/5.2GHz WLAN Operation, Microwave and Optical Technology Letters, Vol. 48, no. 8, pp. 14801483, Aug. 2006.

^{14}S. Gai, Y.C. Jiao, Y.B. Yang, C.Y. Li and J.G. Gong, Design of a Novel MicrostripFed DualBand Slot Antenna for WLAN Applications, Progress in Electromagnetics Research Letters, Vol. 13, pp. 7581, 2010.

^{15}L. Peng and C.L. Ruan, A Microstrip Fed Monopole Patch Antenna with three Stubs for Dualband WLAN Applications, J. of Electromagn.Waves and Appl, Vol. 21, no. 15, pp. 23592369, 2007.

^{16}D.Parkash, R. Khanna, Design of a Dual Band Monopole Antenna for WLAN/WiMAX Applications, in Proc. 7th WOCN, Sep. 68, 2010.

^{17}L. Zhang, Y. C. Jiao, G. Zhao, Y. Song, and F. S. Zhang, Broadband DualBand CPWFed Closed Rectangular Ring Monopole Antenna with A Vertical Strip for WLAN Operation, Microwave and Optical Technology Letters, Vol. 50, no. 7, pp. 19291930, Jul. 2008.

^{18}R. Dakir, J. Zbitou, A. Mouhsen, A. Tribak, A. Sanchez and M. Latrach,New LowCost Broadband CPWFed Planar Antenna, International Journal of Microwave and Wireless Technologies, Research Paper, 6 pages, 11 Dec. 2014.

^{19}J. Pei, A. G. Wang, S. Gao, and W. Leng, Miniaturized TripleBand Antenna with a Defected Ground Plane for WLAN/WiMAX Applications,IEEE Antennas Wireless Propag Lett, Vol. 10, pp. 298301, 2011.

^{20}R. Jothi Chitra, V. Nagarajan, Double Lslot Microstrip Patch Antenna Array for WiMAX and WLAN Applications, Computers and Electrical Engineering, Vol. 39, pp. 10261041, 2013.

^{21}W.C. Liu and C.F. Hsu, DualBand CPWFed YShaped Monopole Antenna for PCS/WLAN Application, Electronics Letters, Vol. 41, no. 7, pp. 390391, Mar. 2005.

^{22}G. Augustin, P. C. Bybi, V. P. Sarin, P. Mohanan, C. K. Aanandan, and K. Vasudevan, A Compact DualBand Planar Antenna for DCS1900/PCS/PHS, WCDMA/IMT2000, and WLAN Applications, IEEE Antennas Wireless Propag Lett, Vol. 7, pp. 108111, 2008.

^{23}Q. Zhao, S. X. Gong, W. Jiang, B. Yang, and J. Xie, Compact WideSlot TriBand Antenna for WLAN/WIMAX Applications, Progress In Electromagnetics Research Letters, Vol. 18, pp. 918, 2010.

^{24}X.L. Sun, J. Zhang, S.W. Cheung, and T.I. Yuk, A Tripleband Monopole Antenna for WLAN and WiMAX Applications, in Proc. IEEE International Symposium (APSURSI), 814 Jul. 2012, pp.12.

^{25}L. Kang, Y.Z. Yin, H. Li, W.J. Huang and S.F. Zheng, DualWideband Symmetrical GShaped Slotted Monopole Antenna for WLAN/WIMAX Applications, Progress In Electromagnetics Research Letters, Vol. 17, pp. 5565, 2010.

^{26}W.C. Liu, Dual Wideband Coplanar WaveguideFed Notched Antennas with Asymmetrical Grounds for MultiBand Wireless Application, IET Microw. Antennas Propag, Vol. 1, no. 5, pp. 980985, Oct. 2007.

^{27}C.Y. Pan, T.S. Horng, W.S. Chenand C.H. Huang, Dual Wideband Printed Monopole Antenna for WLAN/WiMAX Applications,IEEE Antennas Wireless Propag Lett, vol. 6, pp.149151, 2007.

^{28}H. M. El Misilmani, M. AlHusseini, K. Y. Kabalan, and A. ElHajj, A Simple Miniaturized Tripleband Antenna for WLAN/WiMAX Applications, in PIERS Proceedings, Moscow, Russia, Aug. 1923, 2012, pp. 608612.

^{29}Y. Song, Y.C. Jiao, G. Zhao, and F.S. Zhang, Multiband CPWFed TriangleShaped Monopole Antenna for Wireless Applications,Progress in Electromagnetics Research, PIER, Vol. 70, pp. 329336, 2007.

^{30}P. Liu, Y. Zou, B. Xie, X. Liu, and B. Sun, Compact CPWFed TriBand Printed Antenna With Meandering SplitRing Slot for WLAN/WiMAX Applications, IEEE Antennas Wireless Propag Lett, Vol. 11, pp.12421244, 2012.

^{31}W. Hu, Y. Z. Yin, P. Fei, and X. Yang, Compact Tri band SquareSlot Antenna with Symmetrical LStrips for WLAN/WiMAX Applications, IEEE Antennas Wireless Propag Lett, vol. 10, pp.462465, 2011.

^{32}Q.X. Chu and L.H. Ye, Design of Compact DualWideband Antenna with Assembled Monopoles, IEEE Transactions on Antennas and Propagation, vol. 58, no. 12, pp.40634066, Dec. 2010.

^{33}Yi Huang; Kevin Boyle.: Antennas from Theory to Practice, 2008 John Wiley & Sons Ltd.

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Publication Dates

Publication in this collection
Sept 2016
History

Received
14 Oct 2015 
Reviewed
15 Oct 2015 
Accepted
20 June 2016