[ieee 2012 ieee symposium on wireless technology & applications (iswta) - bandung, indonesia...

Elliptical Shaped Antenna With Parasitic Superstrate V. Priyashman1, M. F. Jamlos1, H. Lago1, M. Jusoh1, Z. A. Ahmad1, M. A. Romli1, M. N. Salimi2

1School of Computer and Communication Engineering, Universiti Malaysia Perlis (UniMAP), Kampus Pauh Putra, 02600, Arau, Perlis, Malaysia

2School of Bioproses Engineering, Universiti Malaysia Perlis, Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia [email protected], [email protected], [email protected], [email protected],

[email protected], [email protected], [email protected]

Abstract- This paper introduces the performance of an elliptical shaped antenna with random slots with the use of parasitic element and compares the results between the original patch and the patch with parasitic element mounted on superstrate. 5.8 GHz is the reference or desired frequency set for measuring the performance of this antenna. The purpose of using parasitic element is to optimize the gain and radiation efficiency of this antenna since microstrip antennas has weaknesses in gain and efficiency. Three elliptical shaped slots with different dimensions are designed and connected to each other to allow equal surface current distribution throughout the radiating patch. In addition, 14 cylindrical dots with different radius were designed at the left most center of the patch, making it as a part of the antenna. The parasitic ring element will be supported by 2 different forms of substrate which is foam and a high dielectric constant material. However it is tested one at a time. Adopting the parasitic element method has provided outstanding effects on the antenna’s gain and efficiency. The antenna manages to radiate a maximum gain of 5.801dB. The radiation efficiency and total efficiency of the antenna has improved significantly with the usage of parasitic ring. The proposed antenna can be used for point to point communication and other applications under the same frequency range if the research done is considered successful.

Keywords-elliptical patch antenna; parasitic superstrate;

I. INTRODUCTION Microstrip antennas started to gain popularity in the 1970s

and their contribution became well recognized as the years went by [1]. For all their notable characteristics such as low profile, light weight and economical fabrication cost, their limits in gain and efficiency must not be ignored [2].

An elliptical shaped microstrip antenna has the advantage in terms of geometrical design where complex theoretical analysis can be done in standard coordinate systems [9]. The parasitic ring element is stacked above the radiating patch and this distance will be adjusted to get to optimum gain. The thickness and type of substrate used to hold the ring element also contributes to the gain improvement.

The fact that is intriguing is that the utilization of parasitic element electromagnetically couples with the radiating patch and therefore elevates the gain of the antenna [7]. The existence of cylindrical patches also will have an effect on the performance of the antenna. Microstrip antennas are antennas

that usually produce large bandwidth and occupy less space for the design. This makes it suitable for especially in designing arrays [3, 4, 5, 6]. As the antenna uses the substrate FR4, the fabrication is economical [8-32]. Dimension wise, the antenna has a width of 28.32mm and height of 15.81mm where it is tuned to produce the desired frequency of 5.8GHz.

The paper is organized as follows: In section 2, the detailed design of the antenna will be explained ranging from the elliptical design, the slots, and the connection between slots, the cylindrical patches and the dimensions of the ground plane, substrate, parasitic ring and the substrates used as a support for the ring element. The measurement of the bandwidth, return loss, voltage signal wave ratio, radiation efficiency, directivity and gain is presented in section 3. Finally conclusion will be presented at section 4.

II. ANTENNA DESIGN The antenna is designed using Computer Simulation

Technology (CST) Microwave Studio 2009. The design has 5 layers consist of ground plane, substrate, patch, upper substrate, and ring element.

(a) (b)

(c)

Figure 1. The proposed elliptical patch antenna with random slots (a) Detailed antenna layout (b) The whole design of the antenna (c) The layer by layer description of the proposed antenna patch

ba

c

Cylindrical slot

Slot 1 Slot 2

2012 IEEE Symposium on Wireless Technology and Applications (ISWTA), September 23-26, 2012, Bandung, Indonesia

978-1-4673-2210-2/12/$31.00 ©2012 IEEE 106

For this case, dimension wise, the antenna has a semi major width of 14.16mm and a semi minor length of 7.905mm. The foci calculated are 11.748. Figure 1(a) show that the antenna has 3 main slots. The radiating patch will be excited through coaxial feeding which will go the slot at feed point. The 3 main slots have different dimensions as shown in Figure 1(a). A cylinder of outer radius 0.8mm was used to create the 1st slot and as for the 2nd slot, a torus of large radius 1.2mm and small radius 1.1mm were used. For the largest slot, the torus used has a dimension of large radius 2.4mm and small radius of 2.28mm. The slots created disintegrate the antenna and a small connector with the dimension of 0.4mm for the width and 2.5mm for the length is created and added with the patch to integrate it, as shown in Figure 1 as well. Generally, slots have the ability to reduce the surface-wave excitation in the substrate [11].

The ground plane of the antenna consists of lossy metal which in this case is copper and dimension wise, it is (38.1×22) mm with thickness of 0.035mm. The substrate of the antenna consists of dielectric FR4 with an epsilon of 4.9. Dimension wise, it is (38.1×22) mm with thickness of 1.6mm.

There are two different types of upper substrate used. First is polyimide with a dielectric constant of 3.5. This foam material is chosen as it can be easily reshaped during fabrication [7]. The second substrate used as the mechanical support for the parasitic ring element is Rogers RO03210 with a dielectric constant of 10.2. The second substrate is tested on the antenna for this paper. Dimension wise, both of the foam and substrate material has a width of 38.1mm and length of 22mm. As shown in Figure 1(c), the value of H1 will be varied to get the best end product of electromagnetic coupling in enhancing the gain. Parametric sweep has been done to get the appropriate value of H1 for optimal gain.

III. RESULT AND DISCUSSION Designing an antenna with unorganized slots and dots does

not impede the antenna from producing an outstanding return loss and bandwidth. The radiating element operates at a frequency centered at 5.797 GHz with return loss of -22.87 dB, as shown in Figure 2. After some fine-tuning on the width and length of the radiating patch, the antenna manages to produce the frequency that is just about equal the desired frequency of 5.8 GHz and the most impressive result is the bandwidth of 172.3 MHz produced by the antenna, large enough for it to operate at the desired frequency. Enhancement of bandwidth and return loss of an antenna is one of the positive effects from the slots that are created. More detailed information on this can be studied in [10].

The high dielectric substrate which provides the mechanical support for the parasitic ring element presented an end result that possesses dual band frequency. As shown in Figure 2, the radiating patch produces a dual band frequency centered at 4.591GHz and 5.838 GHz. The bandwidths produced by both of these frequencies are an incredible 188.9 MHz and 253.8 MHz, which is much larger than the original antenna which uses foam for supporting its parasitic element. The return loss for the first frequency band is a terrific value of -40.509 dB

and -15.375 dB for the second frequency band, as depicted in Figure 2. For this configuration, the value of H1 selected is 6mm after going through a range from (1-6) mm. The increment of H1 seems to be directly proportional with its gain and the center frequency also gets shifted upwards. The gain is optimal at 6mm as it degrades after the value of H1 is increased more than 6mm.

(a)

(b) (c)

Figure 2. Simulated results (a) S11 and return loss for the original radiating patch and the patch with parasitic ring mounted on a High Dielectric Substrate (b) Smith Chart of the original radiating patch (c) Smith Chart of the patch with parasitic ring on a high dielectric substrate

From the research conducted, it is found out that the radiating patch with uncoordinated slots demonstrated a disappointing aftereffect in its gain and efficiency. Maximum gain achieved is only a mere 2.122dB, as shown in Figure 3(a). The radiation efficiency of 32.92% with a total efficiency of 32.74% is obviously insufficient for a workable antenna. This proves that low gain and efficiency has been some of the niggling limitations of microstrip antennas. A maximum directivity of 6.948 dBi produced by the antenna is the only encouraging effect from this particular design, as shown in Figure 3(b). However, losing one of its most important parameter which is the gain disapproves the ability of the antenna.

The antenna with stacked parasitic ring element mounted on a high dielectric substrate not only produces a dual band frequency as shown previously but a high gain of 5.801 dB was achieve, an increment of 3.679 dB which also equivalent to an extraordinary percentage of 173.37%. This is displayed in Figure 3(c), while the radiation efficiency of 60.52% and


107

total efficiency of 58.48% achieved during simulation is appropriate enough for a standard antenna performance. The directivity achieved for this antenna is 7.892 dBi as displayed in Figure 3(d). The high dielectric substrate has played a considerable role in improving the gain and efficiency apart from the parasitic ring element. It acts very much the same as a reinforced superstrate layer which not only elevates the gain but also generates dual band frequency. The comparison between the original patch and the antenna with parasitic ring (High Dielectric Substrate) is presented in Table 1.

(a) (b)

(c) (d)

(c)

Figure 3. Simulated results of original antenna and the antenna with parasitic ring (High Dielectric Substrate) (a) Gain of the original antenna (b) Directivity of the original antenna (c) Gain of the antenna with parasitic ring (High Dielectric Substrate) (d) Directivity of antenna with parasitic ring (High Dielectric Substrate) (e) Gain comparison between the original patch and the patch with parasitic ring (High Dielectric Substrate)

Table 1: Comparison between both the antennas’s based on selected parameters

IV. CONCLUSION The effects of parasitic layer with high dielectric substrate as

mechanical support on the performance of an elliptical shaped microstrip patch antenna with random and unsymmetrical slots are presented in this paper. This design shows the effects of the parasitic element which improves the performance of the antenna in terms of gain and radiation efficiency. The research has also provide an in-depth perceptive on the behavior of the antenna with random slots. Furthermore, the research has discovered a new kind combination in terms of parasitic ring and high dielectric substrate to provide gain enhancement on antennas. The distance, H1 of the parasitic element from the lower substrate, FR4 can be tuned to improve the antenna in terms of functionality at the desired frequency range and also the gain and efficiency. This will enable the antenna to be used for point-to-point communication and other modern communication applications depending on the frequency of the radiating patch.

REFERENCES [1] Wonkyu Choi, Yong Heui Cho, Cheol-Sik Pyo, and Jae-Ick Choi “A

High Gain Microstrip Patch Array Antenna Using a Superstrate Layer”, ETRI Journal, Volume 25, Number 5, pp. 407-411, 2003.

[2] R. Garg, P. Bhartia, I. Bahl and A. Ittipiboon, Microstrip antenna design Handbook, Artech House, Norwood, MA, 2000.

[3] N. K. Uzunoglu, N. G. Alexopoulos, and J. G. Fikioris, “Radiation Properties of Microstrip Dipoles,” IEEE Trans. Antennas Propagat.,Vol.AP-27, No. 6, pp. 853–858, 1979.

[4] I. E. Rana and N. G. Alexopoulos, “Current Distribution and Input Impedance of Printed Dipoles,” IEEE Trans. Antennas Propagat., Vol.AP-29, No. 1, pp. 99–105, 1981.

[5] P. B. Katehi and N. G. Alexopoulos, “On the Modeling of Electromagnetically Coupled Microstrip Antennas-The Printed Strip Dipole,” IEEE Trans. Antennas Propagat., Vol. AP-32, No. 11, pp.1179–1186, 1984.

[6] D. M. Pozar, “Analysis of Finite Phased Arrays of Printed Dipoles,” IEEE Trans. Antennas Propagat., Vol. AP-33, No. 10, pp. 1045–1053, 1985.

[7] P. Tilanthe, P.C. Sharma and T.K. Bandopadhyay, “Gain Enhancement Methods for Circular Microstrip Antenna For Personal Communication

Antenna Bandwidth (MHz)

Return Loss (dB)

Directivity (dBi)

Radiation Efficiency

(%)

Original Antenna

172.3 -22.87 6.948 32.92

Antenna with parasitic ring mounted on

high dielectric substrate

188.9 -40.509, 7.982 60.52


108

Sysytems,” IACSIT International Journal of Engineering and Technology, Vol. 3, No. 2, pp.175-178, 2011.

[8] M.F. Jamlos, O.A. Aziz, T.A. Rahman, M.R. Kamarudin and P. Saad, “Reconfigurable Radial Line Slot Array (RLSA) Antenna for Beam Shape And Broad-Side Application”, J. of Electromagn. Waves and Appl., Vol.24, pp. 1171-1182, 2010

[9] Liang C. Shen, “The Elliptical Microstrip Antenna with Circular Polarization”, IEEE Transactions On Antennas And Propagation, Vol.AP-29, No.1, 1981.

[10] V. Sharma, V.K. Saxena, K.B. Sharma, J.S. Saini and D. Bhatnagar, “Probe Feed Elliptical Patch Antenna with Slits for WLAN Application”, Proceedings of International Conference on Microwave, pp. 901-903, 2008

[11] M.F. Jamlos, O.A. Aziz, T.A. Rahman, M.R. Kamarudin and P. Saad, “Reconfigurable Radial Line Slot Array (RLSA) Antenna for Beam Shape And Broad-Side Application”, J. of Electromagn. Waves and Appl., Vol.24, pp. 1171-1182, 2010.

[12] J.D. Kraus and R.J. Marhefka, Antennas For All Applications Third Edition, McGraw Hill, Singapore, International Edition 2003.

[13] M. F. Jamlos, M. R. Kamarudin, M.A. Jamlos and M. Jusoh, “ A novel reconfigurable quadratic antenna for wimax and 4G systems” MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Pages: 416–421, Volume 54, Issue 2, February 2012

[14] M. Jusoh, M. F. Jamlos and M. R. Kamarudin, A compact dual bevel planar monopole antenna with lumped element for ultra high frequency/very high frequency application”, MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Pages: 156–160Volume 54, Issue 1, January 2012

[15] M. Jusoh, M. F. Jamlos, M. R. B. Kamarudin, and M. F. b. A. Malek, "A MIMO antenna design challenges for UWB application," Progress In Electromagnetics Research B, Vol. 36, 357-371, 2012.

[16] M. Jusoh, M. F. Jamlos, M. R. Kamarudin, F. Malek, M. H. Mat, and M. A. Jamlos, “A Novel Compact Tree-Design Antenna (NCTA) with High Gain Enhancement for UWB Application”, J. of Electromagn. Waves and Appl., Vol. 25, 2474–2486, 2011

[17] M. F.Jamlos, O. A. Aziz, T. A. Rahman and M. R. Kamarudin “A Reconfigurable Radial Line Slot Array (Rlsa) Antenna For Beam Shape And Broad Side Application” J. of Electromagn. Waves and Appl., Vol. 24, 1171– 1182, 2010

[18] M. F. Jamlos, T. A. Rahman, and M. R. Kamarudin, “A Novel Adaptive Wi-Fi System With Rfid Technology”, Progress In Electromagnetics Research, Vol. 108, 417-432, 2010

[19] M. F. Jamlos, O. A. Aziz, T. A. Rahman and M. R. Kamarudin “A beam steering radial line slot array (rlsa) antenna with reconfigurable operating frequency”, J. of Electromagn. Waves and Appl., Vol. 24, 1079–1088, 2010

[20] M. F. Jamlos, T. A. Rahman, and M. R. Kamarudin, “Adaptive Beam Steering Of Rlsa Antennawith Rfid Technology”,Progress In Electromagnetics Research, Vol. 108, 65-80, 2010.

[21] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, Z.A.Ahmad, M.A.Romli “ A Dual Bevel Compact Planar Monopole Antenna for UHF Application” Progress In Electromagnetics Research Symposium, 2012

[22] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, Z.A.Ahmad, M.A.Romli “A UWB MIMO Spatial Design Effect on Radiation Pattern” Progress In Electromagnetics Research Symposium, 2012

[23] M.Jusoh, M.F.Jamlos, M.R. Kamarudin “A UWB MIMO Spatial Design Effect on Radiation Pattern” IEEE International Rf And Microwave Conference, 2011

[24] Mohd Faizal Jamlos, Muhammad Ramlee kamarudin, Mohd Fareq Malek, Mohd Aminudin Jamlos, Muzammil Jusoh, Zahari Awang Ahmad, and Abdul Hafiizh Ismail “A Beam Shaping Reconfigurable Radial Line Slot Array(RLSA) Antenna” International Symposium on Antennas and Propagation (ISAP), 2011

[25] Ezla Najwa Ahyat, Nurhidayah Ramli, Muhammad Ramlee Kamarudin, Tharek Abd Rahman and Mohd Faizal Jamlos “A Novel Pattern Reconfigurable Dipole-Yagi Antenna for Wireless Body Area Network (WBAN) Applications, International Symposium on Antennas and Propagation (ISAP)”, 2011

[26] Muzammil Jusoh, Faizal Jamlos and Ramlee Kamarudin “Configuration Study and Analysis of UWB MIMO Antenna Performance”, International Symposium on Antennas and Propagation (ISAP), 2011

[27] M.F.Jamlos, M.Jusoh, M.F. Malek, M.A.Jamlos, Z.A.Ahmad, A.H. Ismail, M.R.Kamarudin and M.H.Muslim, “A unique Reconfigurable Slot Array Antenna for WiMAX Application” IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, 2011

[28] M.Jusoh, M.F.Jamlos, M.R. Kamarudin, M.F. Malek, E.I. Azmi “A Compact Size Antenna with High Gain Enhancement for IEEE 802.15.3”, IEEE Symposium on Wireless Technology Application 2011

[29] M.S. Zulkefli, F. Malek, M.F.jamlos “Novel Dual-Oval Shape Antenna With Bandstop Characteristic For Uwb Application”, IEEE Symposium on Wireless Technology Application 2011

[30] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md Tan, and P. Saad “Reconfigurable Aperture Coupled Planar Antenna Array at 2.3 GHz”, Progress In Electromagnetics Research Symposium Proceedings, Xi'an, China, March 22-26, 2010

[31] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md Tan, and P. Saad “The Gain Effects of Air Gap Quadratic Aperture-coupled Microstrip Antenna Array” PIERS Proceedings, Cambridge, USA, July 5-8, 2010

[32] M. F. Jamlos, T. A. Rahman, M. R. Kamarudin, M. T. Ali, M. N. Md Tan, and P. Saad “Integration of Rfid technology into reconfigurable Aperture coupled patch array (racpa) antenna system” European Conference on Antennas and Propagation 2010, 12-16 April 2010, Barcelona


109

[ieee 2012 ieee symposium on wireless technology & applications (iswta) - bandung, indonesia...

Documents