High Gain High Dense Dielectric Patch Antenna With A Holey Superstrate for 5G Applications M. Asaadi1 A. Sebak2 Abstract ? High gain low profile of a square dense dielectric patch antenna using a perforated superstrate is presented. The proposed patch antenna is excited by the aperture coupled feeding technique. A dielectric superstrate is used to enhance the gain of the proposed antenna. By drilling a set of identical holes in the superstrate layer, the relative permittivity of the dielectric superstrate is reduced, the antenna impedance matching is improved, and the side lobe level is decreased. The implemented antenna achieved a gain of 14.2 dBi at 28.5 GHz with radiation efficiency of 91 %. Furthermore, the proposed antenna has a good radiation pattern. Simulated results using CST software are presented and discussed. For some attractive advantages such as low profile, low cost, light weight, small size, and ease of implementation, the proposed antenna is a good candidate for millimeter-wave wireless communications. 1 (a) INTRODUCTION The demand for low profile high data rate high gain antennas is always the primary pursuit in future 5G applications which leads the research community towards the development of next generation of wireless communication [1]. Highly directional antennas are needed to compensate the signal attenuation which is due to high propagation loss caused by atmospheric absorption [2]. Dielectric resonator have been investigated in the late of 1960, and used as high Q elements in microwave circuits such as filters, and oscillators. Moreover, it has been used as dielectric antennas (DRAs) since 1980s [3]. Recently, a new kind of antenna element, the dense dielectric (DD) patch antenna, is introduced in [4]. Thin dielectric substrate of high permittivity is used to replace the metallic patch is reported in [5]. U-slotted patch antenna fed a single layer frequency selective surface (FSS) superstrate with dissimilar size square patch is designed for broad bandwidth applications [6]. However, the bandwidth is limited to 7.99 % to 12.2 % with an efficiency of 69.1 %. A microstrip patch antenna with superstrate layer is designed at 60 GHz to improve the antenna gain [7]. However, impedance bandwidth of 6.8 % is achieved with high side lobe levels (SLL). Gain enhancement of microstrip patch antenna using a holey superstrate is reported in [8]. The gain of the antenna is about 6.9 dBi and the antenna bandwidth is 3.8 %. In this paper, a holey dielectric superstrate is applied over a square high dense dielectric patch antenna to increase the antenna gain, improve bandwidth and efficiency, and to reduce the side lobe level. The metallic patch is replaced with high dense dielectric patch with relative permittivity of 82. The high dense patch antenna is excited using the aperture coupled feeding technique. Moreover, a set of uniform and identical holes is drilled in a dielectric superstrate layer (b) Figure 1: Geometry of the proposed antenna: (a) side view; (b) top view. to diminish its relative permittivity, and to improve the antenna performance. The proposed antenna offers high gain, high radiation efficiency, wider bandwidth, and low side lobe level. The presented antenna is a good candidate for 5G applications. In section II, the antenna structure is described, and the simulated results are presented in section III. Finally, the conclusions of this work are given in section IV. The geometry of a single square DD patch antenna is illustrated in Fig. (1). The square DD patch is a very low profile with a length Lp=4.1 mm, and a height Hp=0.15 mm with relative permittivity of 82. The DD patch is designed on a Rogers Duoriod 6002 substrate (top layer) with thickness h1=20 mil, (?r=2.94 and tan?=0.0009). The bottom substrate is Rogers RT 3010 with the same thickness of the top substrate. The two substrates has the same length and width (L=25 mm &W= 21 mm). A 50 ? microstrip line is located on the bottom side of the bottom substrate with Lf =10.73 mm, and Wf =0.41 mm. Moreover, the aperture coupling feed method is used to excite a DD patch antenna. The coupling slot in the common ground plane between the two layers has a length Ls=3.5 mm and width Ws=0.23 mm. Furthermore, a superstrate dielectric layer with a relative permittivity of 10.2 and thickness hs =0.64 mm is designed and applied over the DD patch antenna at a distance d=5.5 mm above the DD. Moreover, the ________________________________________________________________________________________ 1 Electrical and Computer Engineering, Concordia University, Montreal, QC, Canada, H3G 1M8, e-mail: [email protected] 2 Electrical and Computer Engineering, Concordia University, Montreal, QC, Canada, H3G 1M8, e-mail: [email protected] Л,((( 1109 dielectric substrate layer is perforated by a set of identical periodical circular holes of diameter D= 1.76 mm (with period P= 3.5 mm and gap g= 1.74 mm) placed along x and y axes. Drilling holes on the dielectric superstrate layer can change the effective permittivity of the material. An effective relative permittivity of the holey superstrate layer is calculated as [9], radiation patterns of the antenna are shown in Fig. 5. The sidelobe levels (SLLs) in the E-plane are < -18 dB, whereas in the H-plane are < - 16.3 dB at 28.5 GHz. For the superstrate without holes case, the corresponding SLLs are < -14 dB and < -12.5 dB in the E-plane and Hplane, respectively. 16 14 ? eff ╖ ╕╕ ╣ 2 ╖ ? з D ╕+ и ╕ 2 ий D + g ╣ ╖ ╕╕ ╣ 2 (1) Effective perm ittivity Fig. (2) illustrates the dependence of calculated effective permittivity on the hole Diameter (D). 12 Gain(dB) з ? з D = ? r и 1 ? ии и 2йD+g й 10 8 6 11 4 10 2 0 26 9 With a holey superstrate Without superstrate With superstrate w/o holes 26.5 27 27.5 8 28.5 29 29.5 30 30.5 31 Figure 4: Gain of the proposed antenna. 7 6 0 5 E-plane H-plane -5 4 0 4 -10 Figure 2: Calculated effective permittivity of the superstrate layer -15 0.5 1 1.5 2 2.5 3 3.5 dB D(mm) 2 28 Frequency ( GHz ) -20 -25 SIMULATED RESULTS -30 The proposed antenna is studied and simulated using CST software package. The reflection coefficient of the antenna is illustrated in Fig. 3. -35 -40 -120 -100 -80 0 -60 -40 -20 0 20 40 60 80 100 120 Theta ( Deg ) -5 Figure 5: E-plane and H-plane of the proposed antenna S11(dB) -10 -15 3 -20 A high gain broadband square high dense dielectric patch antenna using a perforated superstrate is presented and simulated. A simple feeding network is used to excite the proposed antenna. A holey superstrate is applied over the DD patch antenna. Furthermore, drilling a set of circular holes in the superstrate plays a significant role in reducing the side lobe levels and improving the input impedance of the implemented antenna. The antenna exhibits an impedance bandwidth of about 14 %. Moreover, a high gain of 14.2 dBi and radiation efficiency of about 91 % are achieved. At the resonance frequency, the proposed antenna has a good radiation performance with SLL less than -18 dB, -16.3 dB in the E-plane and H-plane, respectively. -25 -30 -35 -40 26 With a holey superstrate Superstrate w/o holes 26.5 27 27.5 28 28.5 29 29.5 30 30.5 31 Frequency ( GHz ) Figure 3: Reflection coefficient of the proposed antenna. It can be noted that the return loss (S11 < -10dB) is good with a wide bandwidth of almost 14 %. Fig. 4 shows the gain of the antenna. It can be seen that the gain is as high as 14.2 dBi at 28.5 GHz. E-plane and H-plane 1110 CONCLUSIONS REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] N. Ashraf, O. Haraz, M. A. Ashraf and S. Alshebeili, "28/38-GHz dual-band millimeter wave SIW array antenna with EBG structures for 5G applications," 2015 International Conference on Information and Communication Technology Research (ICTRC), Abu Dhabi, 2015, pp. 5-8. Y. Li and K. M. Luk, "A 60-GHz Dense Dielectric Patch Antenna Array," in IEEE Transactions on Antennas and Propagation, vol. 62, no. 2, pp. 960963, Feb. 2014. J. K. Plourde and Chung-Li Ren, "Application of Dielectric Resonators in Microwave Components," in IEEE Transactions on Microwave Theory and Techniques, vol. 29, no. 8, pp. 754-770, Aug 1981. H. W. Lai, K. M. Luk and K. W. Leung, "Dense Dielectric Patch Antenna?A New Kind of LowProfile Antenna Element for Wireless Communications," in IEEE Transactions on Antennas and Propagation, vol. 61, no. 8, pp. 4239-4245, Aug. 2013. Y. Li and K. M. Luk, "Wideband Perforated Dense Dielectric Patch Antenna Array for MillimeterWave Applications," in IEEE Transactions on Antennas and Propagation, vol. 63, no. 8, pp. 3780-3786, Aug. 2015. Z. Liu, W. Zhang, D. Fu, Gu, and Z. Ge,? Broadband Fabry-Perot Resonator Printed Antennas Using FSS Superstrate with Dissimilar Size,? Micro. Opt. Technol. Lett, vol.50, no. 6, pp. 1623-1627,2008. H. Vettikalladi, O. Lafond and M. Himdi, "HighEfficient and High-Gain Superstrate Antenna for 60-GHz Indoor Communication," in IEEE Antennas and Wireless Propagation Letters, vol. 8, no. , pp. 1422-1425, 2009. J. H. Kim, C. H. Ahn and J. K. Bang, "Antenna Gain Enhancement Using a Holey Superstrate," in IEEE Transactions on Antennas and Propagation, vol. 64, no. 3, pp. 1164-1167, March 2016. J. B. Muldavin and G. M. Rebeiz, ? Millimeterwave tapered-slot antennas on synthesized low permittivity substrates,? in IEEE Transactions on Antennas and Propagation, vol. 47, no. 8, pp. 12761280, Aug 1999. 1111
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