International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN INTERNATIONAL JOURNAL OF ELECTRONICS AND

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1 INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET) ISSN (Print) ISSN (Online) Volume 3, Issue 3, October- December (2012), pp IAEME: Journal Impact Factor (2012): (Calculated by GISI) IJECET I A E M E A REVIEW ON EFFECTS OF FINITE GROUND PLANE ON MICROSTRIP ANTENNA PERFORMANCE L. Lolit Kumar Singh 1, Bhaskar Gupta 2, Partha P Sarkar 3 1 Department of Electronics & Communication Engineering, Mizoram University, Tanhril, Aizawl , Mizoram, India, llksingh@yahoo.co.in 2 Department of Electronics & Telecommunication Engineering, Jadavpur University, Kolkata , India, gupta_bh@yahoo.com 3 Department of Engineering & Technological Studies, University of Kalyani, Nadia , West Bengal, India, parthabe91@yahoo.co.in ABSTRACT One of the advantages of microstrip patches over conventional antennas is their small size. However, there are many present day applications where even these small radiators are too large. Conventional microstrip antennas assume infinitely large ground plane dimensions and thus they are large in size. The size of ground plane is the limitation of antenna characteristics and compactness. In this paper the review on the analysis of finite ground plane microstrip antenna are presented which are reported on literatures. KEYWORDS: Finite, Ground Plane, Infinite, Microstrip antenna. I. INTRODUCTION Microstrip patch antenna has many advantages like low cost, compact size, simple structure and compatibility with integrated circuitry. For conventional microstrip antennas the size of ground plane is the limitation of antenna characteristics and compactness. Furthermore, their radiation patterns are directional with a relatively high directivity. When ground plane size is reduced overall antenna size also reduces, but simultaneously back lobe size increases, directivity and gain decreases. This is limitation of ground plane size in microstrip antenna. In this paper the review on the analysis of finite ground plane microstrip antenna are presented. 287

2 II. REVIEW Conventional microstrip antennas assume infinitely large ground plane dimensions and thus they are large in size. Hence, their radiation patterns are comparatively directional with a relatively higher directivity. Since in practice, microstrip antennas must have finite ground plane, its effect should be considered in the analysis and design procedures. In 1983, John Huang [1] reported on the effect of finite ground plane on the microstrip antenna radiation patterns. The uniform Geometrical Theory of Diffraction (GTD) was employed for calculating the edge diffracted fields form the finite ground plane of a microstrip antenna. The source field for the radiating patch was calculated by two different methods: the slot theory and the modal expansion theory. Many numerical and measured results were presented to demonstrate the accuracy of the calculations and the finite ground plane effect. It was also demonstrated that the finite edge calculation is essential if accurate pattern levels at wide angles and backlobe information are required. The patterns at planes other than at the principal planes, such as diagonal cuts, can be predicted by GTD with its well-established corner diffraction solution. GTD s creeping wave solution can also be employed to calculate microstrip radiation on a curved surface. In 1983, Erik Lier and Kurt R. Jakobsen [2] analyzed the rectangular microstrip patch antenna extensively with regard to variation in its input impedance and resonant frequency, both for infinite and finite ground plane dimensions. For infinite ground planes, existing formulae had been compared and improved parameters were presented. The influence from the side current radiation was discussed as well. In 1990, A. K. Bhattacharyya [3] reported an analytical technique for the finite ground plane effect on radiation characteristics of a microstrip antenna. Theoretical results show that the gain of a circular patch antenna varies with the ground plane size and is maximum when the radius of the ground plane is 0.63λ 0. It was also found that the input impedance changes widely with the ground plane dimension and decreases with increase in the ground plane radius. The induced current on the ground plane, derived therein, is an approximate one and does not include the edge effects. In order to incorporate the edge effects, a physical theory of diffraction analysis needs to be added. If the ground plane size is not too small, as in the most practical cases, the existing theory gives fairly accurate results for the radiation characteristics. Again, in 1991 A. K. Bhattacharyya [4] reported the effects of ground plane truncation on the impedance of a patch antenna. The input impedance was found to vary widely with the ground plane dimensions, especially for electrically thick substrates. For a given substrate thickness, the surface wave loss was found to be maximum when the ground plane radius is approximately equal to 0.45λ 0 and minimum when radius ~ 0.71λ 0. The resonant frequency also got slightly shifted with ground plane truncation. In 1992, S. A. Bokhari and others [5] introduced a method for the computation of radiation patterns of microstrip antennas on substrates of finite dimensions by a combination of the Mixed Potential Integral Equation technique (MPIE) for patch antennas and the Weak form of the Conjugate Gradient - Fast Fourier Transform (WCG-FFT) method for scattering by the finite ground plane. In 1994, Mohamed Sanad [6] reported Microstrip antennas on very small ground planes for portable communication systems. Analysis for different sizes of ground plane was done using different substrate materials having different thicknesses and different dielectric constants and similar results were obtained. Further, the effect of the size of the ground plane on the radiation patterns of short circuit microstrip antennas were also studied and it was found to be similar to their effect on the patterns of the open circuit Microstrip antennas. In 1997, W. Zhou and P. F. Wahid [7] performed analysis of microstrip antennas on finite ground planes by deriving an integral equation with the use of the reaction theory and 288

3 the dyadic Green s function. The integral equation was solved with the use of the Galerkin method and the current densities on the patch and the ground plane are obtained simultaneously. The far-field radiation pattern is evaluated from currents on the patch, on the ground plane, and on the polarization currents within the substrate. Results were presented for the extreme case where the patch and ground plane are of same size. Microstrip antennas with patch and a ground plane of the same size have large beamwidths compared to their finite ground plane counterparts and exhibit omnidirectional radiation patterns. In 2000, B. Stockbroeckx and others [8] modeled and validated the effect of ground plane and dielectric truncations on the radiation pattern of a slot antenna etched in a substrate covered conductor plane of finite extent. The modeling method is based on the evaluation of analytical Green s functions and numerical computation of single integrals. The importance of considering the surface wave diffraction was demonstrated there. In 2001, D. Chatterjee and others [9] presented the techniques for bandwidth optimization of probe-fed Microstrip antennas on small, finite ground planes. In their paper, a technique based on cavity model and full-wave (MOM) analysis was reported for bandwidth optimization. The results were shown for probefed microstrip antennas on finite ground planes. The results suggest that the cavity model can be used to determine the probe location for the best 2: l VSWR bandwidth on an infinite ground plane, which can be further refined by subsequently using the IE3D code when considering finite ground planes. It has been suggested that the cavity model is suitable for rapid optimization of impedance bandwidth iteratively. In 2002, B. Kolundzija and B. Bajic [10] presented a paper on precise modeling of microstrip patch antennas (finite metalization, substrate and ground), showing rules for efficient and very accurate modeling of microstrip patch antenna taking all stray effects into account (finite substrate, finite ground, etc.). In 2002, Y. Pang and R. Wu [11] reported an analysis of microstrip antennas with inhomogeneous and finite-sized substrates by applying the Finite Element-Boundary Integral (FE-BI) method. In this method, the electric and magnetic fields responsible for radiation on the dielectric boundary of the finite microstrip structures can be solved numerically, without the assumption of infinite substrate. The numerical results were compared with the ones obtained by integral equation method for the case of homogeneous substrates, depicting good consistency with each other. In 2002, Farzad Tavakkol-Hamedani et al [12] presented a treatise on the effects of substrate and ground plane size on the near and far field parameters on the performance of finite rectangular microstrip antennas. It was found that high gain and aperture efficiency values can be obtained for electrically small microstrip antennas and their radiation parameters are mainly controlled by their ground plane dimensions. In 2002, F. T. Hamedani and others [13] developed two techniques based on Electric and Magnetic Field Integral Equation (EFIE and MFIE) formulations of Surface Equivalence principle and Multiple Network theory (SEMN) method. Using pulsed type basis functions, the surface of each homogeneous dielectric body was modeled by small flat segments of arbitrary geometry and constant electromagnetic field. By using the surface equivalence principle along with Green s functions for homogeneous space, the admittance and impedance matrices for the region were computed. Then, the boundary conditions and multiple network theory were applied to determine the overall characteristics of the entire space. Numerical results were compared with measured and simulated ones. In 2003, Pekka Salonen [14] studied effects of various circuit parameters due to a finite-sized ground plane on Planar-Inverted F Antennas (PIFAs). In his report, impedance bandwidth and radiation efficiency as functions of antenna position on a finite-sized ground plane were studied for a dualband U-shaped-slot PIFA (U- PIFA). His results showed that radiation efficiency and impedance bandwidth are strongly dependent on the antenna location with respect to the ground plane. In 2004, V. Natarajan et 289

4 al [15] quantitatively compared the effects of size of a truncated ground plane on the performance of probe-fed rectangular microstrip antenna and wideband U-slot antennas. From his results, it appears that variation of the size of the finite ground plane seems to have similar effect on both U-slot and rectangular patch antennas. In 2004, R. Urban and C. Peixeiro [16] reported the effects of ground plane size on a microstrip antenna performance for small handsets. They also examined effects of small ground plane on bandwidth and gain of PIFA. In 2010, S. I. Latif, and L. Shafai [17] reported nearly equal co-polarized radiation patterns in the two principal planes of circular patch antennas by considering both finite and infinite ground planes. It had been found that for a specific relative dielectric constant material, the E and H-plane co-polarized patterns were nearly equal for a certain range of elevation angles. In 2010, T. J. Cho, and H.M. Lee [18] presented techniques to improve front to back ratio for finite ground microstrip patches. By meandering the edges of the ground plane, the front-to-back ratio of a patch antenna is significantly improved. Further, it had been demonstrated by them that broadside gain of the patch antenna can be decreased by 1.3 dbi while the back lobe level can increase by as much as 7.6 dbi owing to truncation of ground plane. In 2010, L. Lolit Kumar Singh and other [19] have reported on effects of different shaped ground plane on different Patch antenna characteristics with different ground plane shape viz. circular and square and size. These studies have been performed in conjunction with different patch shapes viz. circular and square respectively. As the size of the ground plane reduces, the antenna back lobe increases and front lobe gain decreases in all four cases. However, it is found that circular patch with square ground plane gives less back lobe comparative to other cases. Shifting of resonant frequency with the reduction of ground plane size is also found to be very small for this case. III. CONCLUSION From this review, it is understood that many efforts are going on to overcome some of the limitations of finite size microstrip antenna characteristics. Nevertheless, as regards this issue, useful solutions are still few in number and the solutions often suffer from other problems like distortion of radiation patterns, reduction of gain etc. Author found only few literatures were reported on finite size ground plane. Hence, the author feels that further research is seriously needed in these areas. After all size of ground plane has many effects on microstrip antenna performance. REFERENCES [1] John Huang, The Finite Ground Plane Effect on the Microstrip Antenna Radiation Patterns, IEEE Transactions on Antennas and Propagation, 31(4), 1983, [2] Erik Lier and Kurt R. Jakobsen, Rectangular Microstrip Patch Antennas with Infinite and Finite Ground Plane Dimensions, IEEE Transactions on Antennas and Propagation, 31(6), 1983, [3] A. K. Bhattacharyya, Effects of finite ground plane on the radiation characteristics of a circular patch antenna, IEEE Transactions on Antennas and Propagation, 38(2), 1990,

5 [4] A. K. Bhattacharyya, Effects of ground plane truncation on the impedance of a patch antenna, IEE Proceeding-H, 138(6), 1991, [5] S. A. Bokhari, J. R. Mosig, and F. E. Gardiol, Radiation pattern computation of microstrip antennas on finite size ground planes, IEE Proceedings-H, I39(3), 1992, [6] Mohamed Sanad, Microstrip antennas on very small ground planes for portable communication systems, IEEE Antennas and Propagation Society International Symposium, AP-S Digest, 2, 1994, [7] W. Zhou and P. F. Wahid, Analysis of microstrip antennas on finite ground planes, Microwave and Optical Technology Letters, 15(4), 1997, [8] B. Stockbroeckx, I. Huynen, and A. Vander Vorst, Effect of surface wave diffraction on radiation pattern of slot antenna etched in finite ground plane, Electronics Letters, 36(17), 2000, [9] D. Chatterjee, V. Natarajad, K. F. Lee, and Xiao Wang, Techniques for bandwidth optimization of probe-fed Microstrip antennas on small, finite ground planes, IEEE Antennas and Propagation Society International Symposium, 3, 2001, [10] B. Kolundzija and B. Bajic, Precise modeling of microstrip patch antennas (finite metalization, substrate and ground, IEEE Antennas and Propagation Society International Symposium, 3, 2002, [11] Yi-Hsin Pang and Ruey-Beei Wu, Analysis of microstrip antennas with inhomogeneous and finite-sized substrate, IEEE Antennas and Propagation Society International Symposium, 1, 2002, [12] Farzad Tavakkol-Hamedani, Lotfollah Shafai, and Gh. Z. Rafi, The effects of substrate and ground plane size on the performance of finite rectangular microstrip antennas, IEEE Antennas and Propagation Society International Symposium, 1, 2002, [13] Farzad Tavakkol-Hamedani, Ahad Tavakoli, and Lotfollah Shafai, Analysis of Finite-Microstrip Structures Using Surface Equivalence Principle and Multiple Network Theory (SEMN), IEEE Transactions on Antennas and Propagation, 50(8), 2002, [14] Pekka Salonen, Effects of finite-sized groundplane on radiation pattern deformation, impedance bandwidth, and radiation efficiency of U-PIFA, Microwave and Optical Technology Letters, 36(6), 2003, [15] V. Natarajan, E. Chettiar, and D. Chatterjee, Effect of ground plane size on the performance of a class of microstrip antennas on microwave substrates, IEEE Antennas and Propagation Society International Symposium, 4, 2004,

6 [16] R. Urban and C. Peixeiro, Ground plane size effects on a microstrip patch antenna for small handsets, 15th International Conference on Microwaves, Radar and Wireless Communications, MIKON, 2, 2004, [17] Saeed I. Latif, and Lotfollah Shafai, Effects of Finite Ground Plane and Substrate Permittivity on E- and H- Plane Co-Polarization Patterns of the Circular Patch Antenna, 14 th International Symposium on antenna technology and Applied Electromagnetics (ANTEM) and The American Electromagnetics Conference (AMEREM), [18] T. J. Cho, and H.M. Lee, Front-to-back ratio improvement of a microstrip patch antenna by ground plane edge shaping, IEEE Antennas and Propagation Society International Symposium (APSURSI), [19] L. Lolit Kumar Singh, Bhaskar Gupta, and Partha P Sarkar, Effects of Different Shaped and Size Ground Planes for Different Shaped Patch Antennas Characteristics, International Journal of Recent Trends in Engineering, 4(3), 2010, [20] B.T.P.Madhav and S.S.Mohan Reddy Analytical Study of Ebg Structures On Inset Fed Msp Antennas International Journal of Electronics and Communication Engineering And Technology (IJECET), Volume3, Issue2, 2012, pp , Published by IAEME. [21] Kiran V. Salagare, Mahesh Manik Kumbhar and Prof. A. B. Nandgaonkar, A Planar Inverted F Antenna for Wlan International Journal of Electronics and Communication Engineering and Technology (IJECET), Volume3, Issue2, 2012, pp , Published by IAEME. [22] N.S.Murthy, Dr.S.Sri Gowri and Dr.B.Prabhakara Rao, Two New General Complex Orthogonal Space-Time Block Codes for 6 and 16 Transmit Antenna International Journal of Electronics and Communication Engineering and Technology (IJECET), Volume3, Issue2, 2012, pp , Published by IAEME. [23] Jagadeesha.S, Vani R.M and P.V Hunugund, Size Reduction and Multiband Operation of Rhombusshaped Fractal Microstrip Antenna for Wireless Applications International Journal of Electronics and Communication Engineering and Technology (IJECET), Volume3, Issue2, 2012, pp , Published by IAEME 292