A Coplanar Waveguide Fed Asymmetric Ground Frequency Reconfigurable Antenna

Transcription

1 Received: Mach 28, A Coplana Waveguide Fed Asymmetic Gound Fequency Reconfiguable Antenna Maddela Vijaya Lakshmi 1, 2 * Padhasaadhi Pokkunui 3 Boddapati Taaka Phani Madhav 3 1 Depatment of Electonics and Communication Engineeing, Koneu Lakshmaiah Education Foundation, AP, India 2 Depatment of Electonics and Communication Engineeing, St. Matin s Engineeing College, Secundeabad, Telangana, India 3 Antennas and Liquid Cystals Reseach Cente, Depatment of Electonics and Communication Engineeing, Koneu Lakshmaiah Education Foundation, AP, India * Coesponding autho s btpmadhav@klunivesity.in Abstact: A coplana waveguide fed asymmetic gound fequency econfiguable antenna is designed and analyzed in this pape. The poposed antenna is occupying the compact dimension of 50X45X1.6 mm on FR4 substate with dielectic pemittivity 4.4. The designed antenna is opeating in the wideband fom 2 to 5.8 GHz with coveage in applications like Bluetooth, LTE, Wi-Fi and WLAN. The econfiguable natue of the antenna is analyzed with the switching of PIN diodes placed on the antenna stuctue. The on and off conditions of the diodes D1 and D2 poviding switching between the LTE, Wi-Fi and WLAN bands with good impedance matching. The advantage of PIN diodes includes high powe handling capability, vey low diving voltage and extemely low cost. Hee the switch placement and contol/biasing stategies depend on the type of the switch and the topology of the antenna. The pototyped antenna with biasing is poviding excellent coelation with High Fequency Stuctue Simulato (HFSS) and Compute Simulation Technology (CST) simulation esults. The econfiguability of the antenna and its paametic optimization is analyzed and pesented in this wok. Keywods: Asymmetic gound, Coplana waveguide (CPW), LTE, Reconfiguability, Slot, Wi-Fi, WLAN. 1. Intoduction The apid development in the wieless communication enabling diffeent applications in commecial and militay fields [1]. The technology gowth switching the multidisciplinay fields to utilize the infomation in advanced way and giving diections to wok in novel envionments [2]. The heat of wieless communication lies with icient and poweful antenna design. The antennas ae becoming so compact and smat to seve the needs of moden communication applications [3]. Compact antennas with novel stuctues to povide high gain, bandwidth and econfiguable natue is the cuent eseach aea, which is having lot of scope in the design of advanced communication modules [4]. To allow maximum connectivity in the single wieless platfom, moe numbe of adios is to be integated [5]. Extensive eseach is unde way to develop multiple adio mobile platfoms such as Mobile Intenet Devices, laptops and smat devices to addess diffeent wieless sevices scatteed ove a wide fequency ange [6]. Reseaches designing multiple band antennas to addesses diffeent wieless communication applications such as GPS, GSM, PCS, UMTS, Bluetooth, LTE, Wi-Fi and WLAN etc. [7]. These multi band antennas ae facing seveal challenges when moe and moe wieless sevices ae packed into compact devices [8]. A compaison between antenna solutions and wieless mobile platfoms povide diffeent chaacteistics fo the analysis. If the numbe of

2 Received: Mach 28, antennas is used in wieless mobile platfom then fequency bands, sevices and divesity poblems should be addessed [9, 10]. When multi band/wide band antennas ae used then wieless modules elated divesity poblems should be addessed. The individual adio pefomance is excellent with multiple antennas and good with multi band/wide band antennas. But due to insetion losses at font end the eceive sensitivity will be deceased [11, 12]. The solution fo these poblems can be obtained by designing econfiguable antennas. These econfiguable antennas have multiple advantages like switching to dedicated bands and eduction of intefeence etc. [13]. The econfiguable antenna suppots only one sevice at a time with low powe consumption at low cost [14]. The econfiguable antenna usually equipped with switches that ae contolled by DC bias signals. By toggling these switches in on and off states, the antenna will be econfigued to suppot a dedicated set of opeating fequencies [15]. The econfiguable antennas consist of thee types of configuations like fequency econfiguability, polaisation econfiguability and hybid econfiguability (both fequency and polaisation econfiguability) [16]. Commonly two majo types of switches, PIN diodes and RF MEMS ae used in the design of fequency econfiguable antennas fo wieless applications [17, 18]. In this aticle, PIN diodes ae used to attain fequency econfiguability. The advantage of PIN diodes includes high powe handling capability, vey low diving voltage and extemely low cost [19-20]. Hee the switch placement and contol/biasing stategies depend on the type of the switch and the topology of the antenna [21, 22]. The DC lines ae placed nea the adiating elements affected the antenna esonant chaacteistics [23]. Seveal antennas ae designed with econfiguable natue in the liteatue fo diffeent communication applications [24, 25], but this poposed antenna model is poviding excellent bandwidth fo commecial applications with stable gain. w 2 f Whee 1 2 c f c= fee space velocity of light ε = Dielectic constant of substate (1) 2. The ective dielectic constant of the micostip patch antenna h 1 w 3. The actual length of the patch(l) Whee (2) L L 2 L (3) L c (4) 2 f 4. Calculation of length extension L h w w h h (5) 2. Antenna design A. Design specification The paametes of the antenna ae calculated fom the fomulas given below. 1. Calculation of width (W):

3 Received: Mach 28, Figue. 1 Design methodology (a) (b) (c) (d) Figue. 2 Reconfiguable antenna iteations: (a) antenna 1, (b) antenna 2, (c) antenna 3, and (d) antenna 4 (Poposed) Table 1. Antenna dimensions Paamete In mm Paamete In mm Ls 45 L6 4.5 Ws 50 L L L8 6 L2 11 Wf 2.8 L W1 10 L4 4.4 W2 9.5 L5 7 The design methodology of the poposed antenna and the steps involved in this pocess is pesented in Fig. 1. The dimensions of the antenna wee calculated fom the specified equations and the final dimensions ae optimized in the simulation pocess. The stuctue of the antenna is vey compact in natue and it is occupying the dimension of 50X45X1.6 mm on FR4 substate with pemittivity 4.4. The designed antenna constitutes a monopole on the font side of the substate with combination of L-shaped stub and U-shaped stub as shown in the Fig. 2 (a). A closed gound with slots ae placed on the same side of the substate to excite it to coplana waveguide feeding. Two optimized locations ae identified to place the diodes and the makings ae given on the stuctue with names D1 and D2 as shown in Fig. 2 (d). To opeate the antenna in the band between 2 to 6 GHz, the slots on the adiating stuctue ae optimized with espect to impedance matching of 50 ohms. Coplana waveguide feeding is used fo ease of connection and fo the impovement of bandwidth. The designed antenna is simulated with HFSS and CST micowave studio and the discussion on the esults with analysis is pesented in the subsequent sections. 3. Results and discussion Asymmetic gound stuctued monopole antenna is designed in HFSS and CST tools and the simulated eflection coicient is pesented in Fig. 3. The eflection coicient obtained fom both the tools ae matching pefectly and the bandwidth of 3.8 GHz is obtained fom HFSS and 3.7 GHz fom CST. An impedance bandwidth of 95% fom HFSS tool and 93% fom CST ae obtained. The optimized design of the poposed antenna is simulated using the CST Micowave simulation softwae and the coesponding esults of S-paamete, gain, adiation patten and iciency ae analysed.

4 Received: Mach 28, Figue. 3 Reflection coicient of antenna 1 in CST & HFSS Figue. 5 Fequency econfiguability of antenna 3 Figue. 4 Reflection coicient of antenna 2 Antenna model 2 eflection coicient is simulated and pesented in Fig. 4. The antenna model 2 bandwidth is 3 GHz with coveage fom 3.8 to 5.8 GHz only. This is due to the slot between L- shaped stub to gound plane as shown in Fig. 2 (b). Thee is no cuent flow path between L-shaped stub to gound plane, which causes the degadation in the bandwidth of the antenna. The econfiguable natue of the antenna is examined with placement of diodes at two optimized junctions. Initially D1 is placed at gound plane lowe ight cone, which is adjacent to feedline as shown in Fig. 2 (c). The left side top cone slot is closed in this case to pass the cuent flow fom L-shaped stub. The change in capacitance of the diode is poviding econfiguable behaviou in the opeating band. Capacitance of 0.2 pf is the optimized dimension and fo the emaining values, the poposed antenna poviding notch band chaacteistics in the wideband. Figue. 6 3D Gain at 2.4 GHz The adiation patten of the poposed antenna at 2.4 GHz and 5.6 GHz ae pesented in Figs. 6 and 7. At 2.4 GHz, antenna showing peak ealized gain of 5.14 db and at 3.6 GHz it is aound 2.81 db. The impedance chaacteistics of the antenna is shown in Fig. 8. In the opeating band, the impedance is aound 50 ohms and which is the most consideable paamete in the impedance matching. The adiation patten in pola coodinates fo 2.4 GHz is shown in Figs. 9 and 10. Antenna showing omni diectional patten adiation in H-plane with low coss polaization and dipole like patten in the E-plane. It is also noted that the H-plane patten show elatively low coss polaization adiation. This behaviou is lagely due to the stong hoizontal components of the suface cuent and electic field obseved, when leads to a significant incease of the co-polaization adiation.

5 Received: Mach 28, Figue. 7 3D Gain at 5.6 GHz Figue. 10 H-Plane adiation at 2.4 GHz Figue. 11 Suface cuent distibution at 2.4 GHz Figue. 8 Fequency vs. impedance Figue. 9 E-Plane adiation at 2.4 GHz The suface cuent distibution of the antenna at 2.4 GHz is shown in the Fig. 11. The cuent intensity is focussed at lowe half of the antenna and mostly at feed line and at the adjacent ight cone. The vetical component of the suface cuent which contibutes fo majo adiation and the hoizontal component contibutes the coss polaization. Figue. 12 Pototyped wideband antenna The slots ae made in the maximum cuent flowing paths and diodes ae connected fo fequency tuning. The diodes swithing in the appopoiate locations povided the band stopping and band passing chaacteistics, which intun contolled the fequency tuning opeation.

6 Received: Mach 28, Figue. 13 S 11 measuement of pototyped wideband antenna combination analyze at antennas and liquid cystals eseach cente of KLEF. The measued gain and the simulated gain of the antenna is pesented in Fig. 15 and the measued VSWR with simulated esults ae pesented in Fig. 16. A good coelation between simulation and measuement can be obseved fom the pesented esults. The gain is little bit high at highe opeating band and an aveage gain of 4.5 db is attained in the opeating band. The pototyped antenna is tested fo its econfiguable natue by applying bias voltage to the diodes and the coesponding change in eflection coicient is pesented in Fig. 17. Small shift in the notch band towads highe fequency band can be obseved fom the expeimented esults. Figue. 14 Poposed econfiguable antenna with PIN diodes and biasing lines Figue. 16 Simulated and measued VSWR Figue. 15 Fequency vs. gain The wideband antenna is pototyped on FR4 substate and the modified poposed econfiguable antenna ae pesented in Figs. 12 and 14. Sma connecto 50 ohms is connected at the feed point to measue the antenna paametes though aniitsu Figue. 17 Reconfiguability measuement by applying bias voltage

7 Received: Mach 28, Table 2. Poposed model compaison with liteatue Ref. No Size in Bandwidth Gain in mm in GHz db 1 56X48X X52X X58X , X50X X56X Poposed 50X45X A compaative analysis of poposed antenna with othe models available in the liteatue is pesented in Table 2. As pe the size and bandwidth is concened, the poposed antenna is poviding supeio esults ove othe models. Gain is also little bit high ove othe antennas. 4. Conclusion A stable gain fequency econfiguable antenna with asymmetic gound plane is pesented in this pape. The fequency econfiguability is attained though PIN diodes switching opeation and the obtained simulation esults ae giving good matching with measued esults of the pototyped antenna model. The on and off conditions of the diodes D1 and D2 poviding switching between the LTE, Wi-Fi and WLAN bands with good impedance matching. Peak ealized gain of 5.14 db, aveage gain of 4.5 db and iciency moe than 75% ae the attactive featues of the poposed antenna model. The gain and the iciency can be futhe impoved with the placement of fequency selective suface beneath the gound plane as futue wok and futhe the back lobes can be educed ectively. Acknowledgments We acknowledge ECE of KLEF and DST ECR/ 2016/ , SR/FST/ETI-316/2012 and EEQ/ 2016/ Refeences [1] T. Li, H. Zhai, X. Wang, L. Li, and C. Liang, "Fequency-Reconfiguable Bow-Tie Antenna fo Bluetooth, WiMAX, and WLAN Applications, IEEE Antennas and Wieless Popagation Lettes, Vol. 14, pp , [2] S. Al-Zayed, M. A. Kouah, and S. F. Mahmoud, "Fequency-econfiguable single- and dualband designs of a multi-mode micostip antenna", IET Micowaves, Antennas & Popagation, Vol. 8, No. 13, pp , [3] D. S. Rao and J. L. Naayana, Micostip Paasitic Stip Loaded Reconfiguable Monopole Antenna, ARPN Jounal of Engineeing and Applied Sciences, Vol. 11, No. 19, pp. 1-7, [4] K. Supaja, K15 Nematic Phase Liquid Cystal Mateial Based Double-Dipole Reconfiguable Antenna, Rasayan Jounal of Chemisty, Vol. 10, No. 3, pp , [5] M. A. Babu, B. M. Reddy, R. D. Chaitanya, T. Satish, and T. Anilkuma, A Dual-Polaization Reconfiguable Antenna with Beam Switching Chaacteistics Fo S-Band Applications, ARPN Jounal of Engineeing and Applied Sciences, Vol. 12, No. 16, pp , [6] K. Muthy, K. Umakantham, K. S. Muthy, and B. T. P. Madhav, Reconfiguable Notch Band Monopole Slot Antenna fo WLAN/IEEE n Applications, Intenational Jounal of Intelligent Engineeing and Systems, Vol. 10, No. 6, pp , [7] T. V. Ramakishna, N. Kian, B. Savani, N. Vamsi, and K. L. Yamini, Fequency Reconfiguable Antenna fo Ku-Band Applications, ARPN Jounal of Engineeing and Applied Sciences, Vol. 12, No. 22, pp , [8] G. J. Devi, Reconfiguable MIMO Antenna Fo 5G Communication Applications, Intenational Jounal of Pue and Applied Mathematics, Vol. 117, No. 18, pp 89-95, [9] U. Ramya, M. A. Babu, and M. V. Rao, Double Notch Reconfiguable Monopole Antenna with Stub Loaded DGS, Intenational Jounal of Pue and Applied Mathematics, Vol. 117, No. 18, pp , [10] P. F. Banu, G. H. S. Teja, P. Pashanth, and K. L. Yamini, Octagonal Shaped Fequency Reconfiguable Antenna fo Wi-Fi and Wi- MAX Applications, Lectue Notes in Electical Engineeing, Vol. 471, pp , [11] G. Lalitha, S. M. Pavez, J. Naveen, D. Mani Deepak, and A. N. M. Kumai, A Fequency Reconfiguable Spial F-Shaped Antenna fo Multiple Mobile Applications, Lectue Notes in Electical Engineeing, Vol. 471, pp , [12] K. S. R. Muthy, K. Umakantham, and K. S. N. Muthy, U-Shaped Slotted Reconfiguable Monopole with WIMAX Band Notching, Jounal of Advanced Reseach in Dynamical and Contol Systems, Vol. 9, No. 14, pp , 2017.

8 Received: Mach 28, [13] B. S. Pasad and P. M. Rao, CPW Fed T-Stub And U-Slot Reconfiguable Antenna fo Wi-Fi And WLAN Communication Applications, Jounal of Advanced Reseach in Dynamical and Contol Systems, Vol. 9, No. 14, pp , [14] A. Vamseekishna, Y. Nagajuna, S. L. Manasa, V. Mouya, and Y. Yaswant, Reconfiguable Notch Band Antenna Using PIN Diodes, Jounal of Advanced Reseach in Dynamical and Contol Systems, Vol. 9, Issue 14, pp , [15] B. S. Pasad and P. M. Rao, Coplana Wave guide fed fok shaped fequency econfiguable antenna fo LTE, Wi-Fi and WLAN applications, Intenational Jounal of Engineeing and Technology, Vol. 7, No. 1.1, pp , [16] Y. B. Dhanade, K. Seelakshmi, P. Boa, and M. Mudlia, Fequency Reconfiguable Dual Band Antenna fo Wieless Communications, Jounal of Advanced Reseach in Dynamical and Contol Systems, Vol. 9, No. 14, pp , [17] M. V. Rao, Design and Analysis of Stepped Reconfiguable Rectangula Patch Antenna fo LTE, Vehicula and Ulta Wideband Applications, Intenational Jounal of Engineeing and Technology, Vol. 7, No. 1.1, pp , [18] P. Padhasaadhi and T. Anilkuma, Design of Compact Reconfiguable Antenna with Tiple Band Switchable Chaacteistics, Intenational Jounal of Engineeing and Technology, Vol. 7, No. 1.1, pp , [19] A. Vamseekishna, A Fequency Reconfiguable Antenna with Bluetooth, Wi-Fi and WLAN Notch Band Chaacteistics, Intenational Jounal of Engineeing and Technology, Vol. 7, No. 2.7, pp , [20] X. L. Yang, J. C. Lin, G. Chen, and F. L. Kong, "Fequency Reconfiguable Antenna fo Wieless Communications Using GaAs FET Switch", IEEE Antennas and Wieless Popagation Lettes, Vol. 14, pp , [21] L. Ge and K. M. Luk, "Fequency- Reconfiguable Low-Pofile Cicula Monopola Patch Antenna", IEEE Tansactions on Antennas and Popagation, Vol. 62, No. 7, pp , [22] S. Al-Zayed, M. A. Kouah, and S. F. Mahmoud, "Fequency-econfiguable singleand dual-band designs of a multi-mode micostip antenna", IET Micowaves, Antennas & Popagation, Vol. 8, No. 13, pp , [23] Q. Liu, N. Wang, C. Wu, G. Wei, and A. B. Smoldes, "Fequency Reconfiguable Antenna Contolled by Multi-Reed Switches", IEEE Antennas and Wieless Popagation Lettes, Vol. 14, pp , [24] D. S. R. Kian and V. Alekhya, An Asymmetic Liquid Cystal Polyme Based Factal Slotted UWB Monopole Antenna with Notch Band Chaacteistics, Rasayan Jounal of Chemisty, Vol. 10, No. 3, pp , [25] B. T. P. Madhav, T. V. Rao, and T. A. Kuma, Design of 4-Element Pinted Aay Antenna fo Ulta-Wideband Applications, Intenational Jounal of Micowave and Optical Technology, Vol. 13, No. 1, pp 8-17, 2018.