This full-text paper was peer-reviewed and accepted to be presented at the IEEE WiSPNET 2017 conference. Design of Multiband Monopole Antenna for Wireless Applications T. Sathiyapriya,1 V. Gurunathan,2 R. Sudhakar3 and A. Shafeek4 ECE Department, Dr. Mahlingam Collge of Engineering and Technolgy, Pollachi-03. Email: 1 [email protected] 2 [email protected] 3 [email protected] 4 [email protected] Abstract—A highly compact microstrip-fed monopole antenna for Wireless Local Area Network (WLAN) and satellite communication is proposed. The proposed antenna design has different geometry manipulation to achieve multi band performance with reduced size than existing antenna. The antenna consists of compact rectangular patch as a radiator that is fed directly by a 50 Ω microstrip line. The rectangular patch consists of Land U-shaped slots and ground plane. The proposed antenna consists of very small radiating patch when compared to existing double- and triple-band monopole antennas. The radiator is highly compact with the size of 12.5 × 10 × 1.6 mm3 . The simulation results show that the designed antenna is capable of operating over 3.5 GHz, 4–4.9 GHz and 5–8 GHz frequency bands while rejecting frequency ranges between these three bands. The design has been simulated using Advanced Design System (ADS) 2016. Index Terms—WLAN, Multiband, Size reduction, Advanced Design System. I. I NTRODUCTION The high-performance spacecraft, aircraft, missile and satellite applications, where size, weight, cost, performance, ease of installation and aerodynamic proﬁle are constraints, and other Government and commercial applications, such as mobile radio and wireless communications that have similar speciﬁcations. To meet these requirements, microstrip antenna is the most suitable candidate. Many antenna designs are already present in the market that will successfully meet the requirements. Microstrip antennas inherently have a narrow bandwidth and hence bandwidth enhancement is usually demanded. In addition, present day wireless communication systems usually require smaller size antennas. Thus size reduction and bandwidth enhancement are becoming major design considerations in the case of microstip antennas. For this reason, studies to achieve compact and broadband operations of microstrip antennas have greatly increased. Revolution in Information technology is one of the major breakthroughs in wireless communications. The unlicensed frequency band of 2.4–2.5 GHz popularly known as industrial, scientiﬁc and medical (ISM) band, has become a widespread choice for a range of wireless applications. But, this popularity is causing congestion, resulting in more interference and eventually degrading the performance of wireless links. Additionally, the growing level of interference from the neighboring wireless devices enacts tough constraints on the transceiver design, starting with the speciﬁed level for the transmitted power and ending with the speciﬁed receiver noise c 978-1-5090-4442-9/17/$31.00 2017 IEEE ﬁgure. To meet the required performance from a wireless link, and at the same time relax the transceiver design constraints, one can utilize the principle of Multiband antenna systems. In wireless devices, the space might become limiting criteria for multiple antenna conﬁgurations. Thus, how to implement antennas into a small multi-standard device becomes a challenge. One way to address this problem is reduce the number of antenna elements by covering multiple Radio interfaces at wide frequency range by using dual band [1–6], Triple Band [7–10], multi-band [11–20] and wideband antennas , . For example the WLAN uses a lower frequency band 2.4–2.484 GHz, for the 802.11 b/g standards, and two higher frequency bands, 5.15–5.35 GHz and 5.725–5.825 GHz, for the 802.11a standard. As the demand for smaller sizes of wireless devices increases, antennas designers are making incredible efforts in attempts to reduce the physical sizes of the antennas, yet covering all the three operation bands. Section I provide the introduction of antenna and proposed antenna design. The related work details are described in Section II. The conﬁguration of the proposed antenna is described in Section III. Simulation Results are presented in Section IV. II. R ELATED W ORKS A Rectangular Microstrip Antenna is realized by two different single-slotted single band rectangular microstrip antennas with a slotted ground plane. The length and position of each open-ended slot is varied in order to make the antenna operate in a suitable resonant bands at 5.15–5.35 GHz and 5.725–5.825 GHz of WLAN IEEE 802.11a . The slot antennas with a slotted structure and an inverted-L slot structure for covering the wireless communication operations are developed . Two asymmetric horizontal strips are used to provide two broadband dual-resonance modes. As a result, a dual-band antenna for covering the 2.4 and 5-GHz WLAN systems is achieved. By widening the right horizontal strip and using an L-shaped notch in the right horizontal strip, a multiband antenna covering DCS1800, PCS1900, UMTS2000, and 2.4- and 5-GHz WLAN bands is then implemented which is both compact in size and multiband operation . Inverted U shaped slot in a radiator and defected ground plane are used to operate over WLAN and Wi-MAX frequency bands . U-shaped slots on the patch geometry have been used to obtain dual band operation . 924 This full-text paper was peer-reviewed and accepted to be presented at the IEEE WiSPNET 2017 conference. TABLE II A NTENNA D IMENSIONS . TABLE I S UBSTRATE S ETUP S PECIFICATIONS . Speciﬁcations Antenna Geometry Dielectric constant Tangent loss Substrate thickness Conductor material Conductor layer thickness r tan δ H T 4.4 0.001 1.6 mm Copper 0.052 mm Fig. 1. Geometry of the multiband monopole antenna. (a) Top view. (b) Side view. In this paper, a planar multi band monopole antenna is simulated which consists of highly compact radiator to cover four operating bands of wireless communication. The radiator consists of L-shaped slits and U-shaped slots to make the antenna resonating at around 3.5 GHz and 5–7 GHz respectively. Today, the main aim of commercial communication is to provide high speed connectivity and easy access to networks within effective cost. Since FR4 substrate is less cost and most suitable for low frequency wireless applications. The simulations are carried out in Advanced Design System (ADS 2016). III. A NTENNA D ESIGN The multiband applications of an antenna such as applications in WLAN, Wi-MAX, C-Band satellite communication and 2.4 GHz ISM band can be easily achieved with this type of antenna by adjusting the dimensions and positions of the slots on the upper patch and on the ground plane. The substrate used here is FR4 with speciﬁcations as given in Table I. Fig. 1 shows the geometry of a compact monopole antenna for wireless applications. It consists of rectangular radiating Symbol Value (mm) L W L1 W1 Lg Wg 11 18 12 10 2.5 11 patch, 50 Ω microstrip feed line and a bottom metal plane as ground plane. The antenna has two U shaped slots around the centre of the patch. The antenna which is rectangular in shape has an area of 12.5 × 10 × 1.76 mm3 before the slots were made. It consists of two U shaped slots and two L shaped slits which decides the multiband performance of proposed antenna. The relative dimensions of the antenna and the ground plane are given in Fig. 1 and Table II. Microstrip patch antenna usually has single band operation with very narrow bandwidth. There were lots of techniques to improve the bandwidth as desired. Multiband antenna is one of the methods to enhance the performance of antenna to make it working for different applications at different frequency ranges. Different shapes of slots and slits at various positions on radiating patch will deﬁnitely affect the current ﬂow through the conductor which in turn has an impact on antenna performance parameters like radiation pattern, gain, directivity, bandwidth and etc. Proper selection of slot or slit shape and location on patch decides the improved performance of the antenna. Two L shaped slits and U shaped slots are selected for proposed antenna design to simultaneously achieve multiband radiation and size reduction. Two L shaped slits contributing for triple band performance at 3.5 GHz and 5.5 GHz. By etching U shaped slots at the center of the patch gives four bands with reduction in patch area. The simulation result of normal patch antenna with same size of proposed antenna will show single band response. The consequent sections will give performance of proposed antenna. Both the results are compared simultaneously to prove the performance of the proposed antenna. Fig. 2 shows the geometry of antenna with two L shaped slits etched on both side of patch antenna. The simulation results shows that L shaped slits contributed for triple band characteristics of proposed antenna design. Three bands occur at 3.9 GHz, 4.84 GHz, and 5.704 GHz (see Fig. 3). IV. S IMULATION R ESULTS AND D ISCUSSION The proposed antenna characteristics are examined using the tool Advanced Design System (ADS) 2016. Here the monopole antenna is implemented with slotted patch antenna as shown in Fig. 4. Comparing to antenna 1, two U slots at the centre of the patch provides multiband performance. Fig. 5 shows the simulation results of proposed antenna with 925 This full-text paper was peer-reviewed and accepted to be presented at the IEEE WiSPNET 2017 conference. Fig. 2. Layout of the antenna with L shaped slits. Fig. 5. Simulation result of the antenna with L shaped slits and U shaped slots. Fig. 3. Simulation result of the antenna with L shaped slits. Fig. 6. Simulated elevation plane pattern of the antenna at 5.5 GHz. Fig. 4. Layout of the antenna with L shaped slits and U shaped slots. four rejection band. The lower band covers 3.6 GHz and other bands are covering the range from 4.4 GHz to 8 GHz. The second band covers wide range of frequencies including 5 GHz WLAN band. The 5 GHz WLAN band includes frequency bands of IEEE 802.11a, IEEE 802.11g, and IEEE 802.11n. Various plots are simulated and analyzed to assure the performance of proposed antenna. Radiated power pattern is analyzed in both azimuthal and elevation plane at three different notch frequencies. Figs. 6 and 7 shows the 2D radiation pattern of proposed antenna at 5.5 GHz in both elevation and azimuthal plane. 926 This full-text paper was peer-reviewed and accepted to be presented at the IEEE WiSPNET 2017 conference. Fig. 10. Simulated elevation plane pattern of the antenna at 3.5 GHz. Fig. 7. Simulated azimuthal plane pattern of the antenna at 5.5 GHz. Fig. 8. Simulated elevation plane pattern of the antenna at 4.4 GHz. Fig. 11. Simulated azimuthal plane pattern of the antenna at 3.5 GHz. Fig. 12 shows the 3D radiation pattern of the proposed antenna, in which red color indicates maximum radiation and green color indicates minimum radiation. V. C ONCLUSION Fig. 9. Simulated azimuthal plane pattern of the antenna at 4.4 GHz. Similarly Figs. 8 and 9 gives the radiate power at 4.4 GHz. After observing power radiated at 3.5 GHz from Figs. 10 and 11, the proposed antenna shows good radiating capabilities at all three center frequencies. A compact multiband monopole antenna is proposed in this paper. It uses different shapes of slots and slits in the upper patch and includes truncated ground plane. The slots and slits introduced in the patch reject all undesired bands and provides the resonance at the desired resonant frequencies. The proposed monopole antenna can offer adequate impedance bandwidths and omni-directional radiation patterns for wireless operations. Three resonant frequencies are obtained at 3.5 GHz,4.7 GHz and 5.8 GHz respectively with an appreciable return loss. The antenna is suitable for the applications like 5 GHz (WLAN applications of IEEE 802.11a, IEEE 802.11n & IEEE 802.11ac) & 5.5 GHz (IEEE 802.11 WiMAX) and also covers the part of 4–8 GHz (C-band) satellite frequency band. Therefore, the proposed design of monopole antenna 927 This full-text paper was peer-reviewed and accepted to be presented at the IEEE WiSPNET 2017 conference.       Fig. 12. 3D Radiation pattern of proposed antenna.  is highly compact and primary option for many commercial wireless applications.  R EFERENCES   C. H. Pan, T. S. Hong, W. S. Chen, and C. H. Haung, “Dual wideband printed monopole antenna for WLAN/WiMAX applications,” IEEE Transactions on Antennas and Propogation Letters, vol. 6, pp. 149–151, 2007.  H. D. Chen, J. S. Chen, and Y. T. Cheng, “Modiﬁed inverted-L Monopole antenna for 2.4/5 GHz dual-band operations,” Electronics Letter, vol. 39, pp. 1567–1568, Oct. 2003.  M. N. Hasan, S. W. Shah, M. I. Baba, and Z. Sabir, “Design and simulation based studies of a dual band u-slot patch antenna for WLAN application,” in Proceedings of 14th International Conference on Advanced Communication Technology, 2012, pp. 997–1001.  T. H. Kim and D. C. Park, “CPW-fed compact monopole antenna for dual-band WLAN applications,” Electronics Letters, vol. 40, no. 18, pp. 1094–1095.  Sheng-Bing Chen, Yong-Chang Jiao, Fu-Shun Zhang, and Qi-Zhong Liu, “Modiﬁed T-shaped planar monopole antenna for 2.4/5GHz WLAN applications,” in Asia Paciﬁc Conference Proceedings of Microwave Conference, vol. 4, 2005, pp. 2714–2716.  U. Chakraborty, A. Kundu, S. K. Chowdhury, and A. K. Bhattacharjee, “Compact dual-band microstrip antenna for IEEE 802.11a WLAN application,” IEEE Antennas and Wireless Propagation Letters, vol. 13, pp. 407–410, 2014  Alaknanda Kunwara, Anil Kumar Gautamb, and Karumudi Rambabu “Design of a compact U-shaped slot triple band antenna for        928 WLAN/WiMAX applications,” AEU - International Journal of Electronics and Communications, vol. 71, no. 1, pp. 82–88, Jan. 2017. Y. Zou Liu, B. Xie, X. Liu, and B. Sun, “Compact CPW-fed triband printed antenna with meandering split-ring slot forWLAN/WiMAX applications,” IEEE Antennas Wireless Propag. Lett., vol. 11, p. 777, 2012. Y. J. Wu, B. H. Sun, J. F. Li, and Q. Z. Liu, “Triple band Omni directional antenna for WLAN application,” Prop. Electromag. Research. vol. 76, pp. 477–484, 2007. J. R. Panda and R. S. Kshetrimayum, “A printed trident shaped triple-band monopole antenna for wireless applications,” in International Conference on Signal Processing and Communications, Bangalore, 2010. HanJiang Liu, RongLin Li, Yan Pan, XuLin Quan, Li Yang, and Liang Zheng, “A multi-broadband planar antenna for GSM/ UMTS/LTE and WLAN/WiMAX handsets,” IEEE Transactions on Antennas and Propagation, vol. 62, no. 5, pp. 2856–2860, May 2014. Y. Song, Y. C. Jiao, H. Zhao, Z. Zhang, Z. B. Weng, and F. S. Zhang, “Compact printed monopole antenna for multiband WLAN applications,” Microwave Opt. Technol. Letters, vol. 50, no. 2, pp. 365–367, Feb. 2008 S. B. Chen, Y. C. Jiao, W. Wang, and F. S. Zhang, “Modiﬁed t-shaped planar monopole antenna for multiband operation,” IEEE Transactions on Microw. Theory and Techniques, vol. 54, no. 8, Aug. 2006. S. C. Basaran, U. Olgun, and K. Sertel, “Multiband monopole antenna with complementary split-ring resonators for WLAN and WiMAX applications,” Electronics Letters, vol. 49, no. 10, May 2013. W. Hu, Y. Z. Yin, X. Yang, and P. Fei, “Compact multi resonator loaded planar antenna for multiband operation,” IEEE Trans. Antennas Propag. Lett., vol. 61, p. 326, 2013. W. T. Li, Y. Q. Hei, J. Yang, and X. W. Shi, “Novel design of printed multiband antenna for wireless applications,” in IEEE Conference Publication vol. 3, 2012, pp. 1–3. H. Lavakhamseh, Ch. Ghobadi, J. Nournia, and M. Ojaroudi, “Multi resonance printed Monopole Antenna for DCS/WLAN/WiMAX Applications,” Microwave and Optical Technology Letters, vol. 54, no. 2, Feb. 2012. Rengasamy Rajkumar and Kommuri Usha Kiran, “A compact metamaterial multiband antenna for WLAN/WiMAX/ITU band applications,” AEU - International Journal of Electronics and Communications, vol. 70, no. 5, pp. 599–604, May 2016. N. Prema and Anil kumar, “Design of multiband microstrip patch antenna for C and X band,” Optik - International Journal for Light and Electron Optics, vol. 127, no. 20, pp. 8812–8818, Oct. 2016. Mahdi Moosazadeh and Sergey Kharkovsky, “Compact and small planar monopole antenna with symmetrical L- and U -shaped slots for WLAN/WiMAX applications,” IEEE Antennas And Wireless Propag. Lett., vol. 13, p. 338, 20strip14. N. Azenui and H. Y. D. Yang, “A printed crescent patch antenna for ultra wideband applications,” IEEE Antennas and Wireless Propog. Letters, vol. 6, pp. 113–116, 2007. N. P. Agarwall, G. Kumar, and K. P. Ray, “Wide-band planar monopole antennas,” IEEE Trans. Antennas Propog., vol. 46, no. 2, pp. 294–295, 1998. C. A. Balanis, Antenna theory analysis and design 2nd ed. (Asia) Singapore: John Wiley& sons.