Miniaturize Microstrip Patch Antenna with DGS Technology

IJSRD - International Journal for Scientific Research & Development| Vol. 4, Issue 03, 2016 | ISSN (online): 2321-0613

Miniaturize Micro Strip Patch Antenna with DGS Technology Jagdish Chaudhary1 Gautam D. Makwana2 1 P.G Student 2Assistant Professor 1,2 SK Patel Engineering College, Visnagar, Gujarat, India Abstract— A defected ground structure(DGS) is proposed to compact size of microstrip patch antenna. The main goal of this paper is to miniaturize a microstrip patch antenna resonating at 2.4 GHz. for this purpose DGS has been employ to shift resonance of an initial MPA from 5.5GHz to 2.4GHz by disturbing the antenna’s current distribution. The propose DGS is incorporated in the ground of MPA to improve its performance. Finally a miniaturization up to 82.83% with respect to conventional MPA. The simulation results can be carried out by CST software. Key words: Microstrip patch antenna (MPA), Defected Ground Structure, Miniaturization

𝑐 2 √ 2𝑓𝑟 εr + 1 2) Effective length of the patch 𝑐 𝐿𝑒𝑓𝑓 = 2𝑓𝑟 √𝜀 𝑟𝑒𝑓𝑓 𝑤=

I. INTRODUCTION Microstrip patch antennas are most commonly used now days. Due to its low-profile, ease of fabrication, versatility, light weight it has gained more momentum than other antennas. Microstrip antennas are often known as planar antenna because its elements are usually flat [2]. The radiating patch can be square, rectangle, circle, hexagonal or any other shapes. Although there are few demerits which MPAs suffers like- low efficiency, narrow bandwidth, less gain because of their small size and high return loss. Many researches till now have been done in MPAs to show better result and in removing all the demerits. Many designs have already proposed in enhancing all the demerits. In this paper also a design is proposed to compact of microstrip patch antenna [3]. Many types of miniaturization techniques, such as using of dielectric substrate of high permittivity, slot on the patch, DGS at the ground plane or a combination of them have been proposed and applied to microstrip patch antennas [6]. In this paper DGS are used to miniaturize the rectangular microstrip antenna. The present work deals with design and analysis of a rectangular compact microstrip antenna for wireless application. The design incorporate like hammer shaped defected ground structure which is in the ground plane, which disturbs shielded current distribution in ground plane [6], [8]. Initially the antenna is designed for the resonant frequency of 5.5GHz and the using DGS the resonant frequency is shift to 2.4 GHz. So a size reduction of 82.83 % is achieved..

3) Extended length 𝑤

Δ𝐿 = 0.412 × ℎ

[𝜀𝑟𝑒𝑓𝑓 + 0.3] [ ℎ + 0.264]

[𝜀𝑟𝑒𝑓𝑓 − 0.258] [𝑤 + 0.8] ℎ 4) Actual length of patch L=Leff - 2∆L III. MICROSTRIP PATCH ANTENNA RESONATING AT 5.5GHZ The proposed microstrip patch antenna’s structure shown in Fig. 2. In this design the substrate FR4 is used due to its low cost and easy fabrication. The substrate height is 1.6 mm, the dielectric constant is 4.4 and the loss tangent is 0.021. The dimensions of our antenna are optimized by using CST Microwave Studio tool.

II. ANTENNA STRUCTURE AND DESIGN Microstrip antennas are designed with different types of substrate like FR4, PTFE, RT duroid 5880 etc depending upon design requirement. The Microstrip patch antennas are basically designed by etching the antenna structure on the substrate. Depending on the relative permittivity, operating frequency the width, length, feed distances are decided [3]. Here FR4 substrate of thickness 1.6 mm and relative permittivity of 4.4 is used. So the desired length and width can be calculated design equation [1]. 1) Width of patch

Fig. 2: Top view of our patch antenna Resonating at 5.5 GHz

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Miniaturize Micro Strip Patch Antenna with DGS Technology (IJSRD/Vol. 4/Issue 03/2016/199)

properties, specially the resonance frequency. Then we introduce a third circle of DGS at middle of two circles and do the same study. Both of these simulations have been carried out by CST Microwave Studio. A. With Two Circle Dgs: In absence of DGS, we have seen in Section II that the resonance frequency of our microstrip patch antenna is at 5.5 GHz. Now with two circles type DGS with radius equal to 5mm introduced at the edge of patch with y-center 9 and -9, the simulation result obtained for the return loss is shown in Fig. 6. We can see that the resonance frequency has been significantly influenced by the DGS, namely, it has been brought to about 4.9 GHz. Fig. 3: Simulated return loss of the patch Antenna Resonating at 5.5 GHz. The simulated return loss obtained for this antenna is shown in Fig. 3. We can see that the adaptation is better than 10 dB and the resonance frequency is around 5.5 GHz. IV. DEFECTED GROUND STRUCTURE DGS is an etched periodic or non-periodic cascaded configuration defect in ground of a planar transmission line (e.g., coplanar, microstrip and conductor backed coplanar wave guide) which disturbs the shield current distribution in the ground plane cause of the defect in the ground. This disturbance will change characteristics of a transmission line such as line capacitance and inductance. In the other word, any defect etched in the ground plane it will increasing effective capacitance and inductance[8]. Different types of shapes etched in the microstrip line ground plane is shown In Fig. 4, including spiral head, arrowhead-slot and H-shape slots and more complex DGSs to improve the circuit presentation are open-loop dumbbell, square open-loop with middle section slot. The newly develop DGS unit can control the two transmission zeros near the pass band edges and easily control the frequency of the slot by changing the length of the metal fingers [9]

Fig. 5: Microstrip patch antenna with two circles DGS (a =5 mm, b = 5 mm)

Fig. 6: Simulation Of Return Loss For The Antenna With Two Circles DGS:

Fig. 4: Different Geometries of DGS V. MICRO STRIP PATCH ANTENNA WITH DGS We deploy DGS in order to shift the resonance frequency of the microstrip antenna previously presented in Fig. 1. First we introduce two circle type DGS with radius equal to 5mm and it is symmetrically located at edge of the patch with ycenter 9 and -9 and we study its eff ect on the antenna

B. With Three Circle Dgs: Now we introduce the third circle of DGS at middle of two circles radius equal to 7.80mm to our proposed antenna as shown in Fig. 7. With three circle DGS, the obtain return loss for this structure is -20.25dB presented in Fig. 8 and is also shows that the resonance frequency has been shifted to around 2.4 GHz. Thus, we can say that we have obtained very acceptable result with simulation. Namely, we have designed microstrip patch antenna with DGS resonating at 2.4 GHz. microstrip patch antenna with DGS resonating at 2.4 GHz.


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Fig. 7: Microstrip patch antenna with three circle DGS (a =7.80 mm, b = 14.80mm). Fig. 10: Microstrip Patch Antenna With DGS Resonating At 2.4ghz B. Radiation Pattern: The radiation patterns shown in Figs. 11 and 12 are obtained for our conventional microstrip antenna and for a DGS microstrip antenna at 2.4 GHz, respectively. In these figures we can see that the simulated gain for the conventional antenna is 8.57 dB as for the DGS antenna the simulated gain is 8.62 dB.

Fig. 8: Simulation of return loss for the Antenna with three circles DGS. VI. COMPARISON BETWEEN CONVENTIONA L ANTENNA AND ANTENNA WITH DGS AT 2.4GHZ A. Size Comparison: Figure 9 and 10 shows a size comparison between a conventional microstrip antenna and the antenna that we have previously designed using three circles types DGS, and both resonating at 2.4 GHz. We can see that employing a defected ground plane beneath the microstrip patch antenna allows us to reduce the conventional surface up to 82.83%.

Fig. 11: Radiation pattern for the conventional antenna

Fig. 12: Radiation pattern for the DGS antenna VII. CONCLUSION

Fig. 9: Conventional microstrip patch antenna resonating at 2.4GHz

The miniaturized microstrip patch antenna has been carried out by DGS structure at 2.4 GHz frequency. Initially microstrip patch antenna resonates at 5.5 GHz after employing three circle DGS initially shift resonant frequency 2.4GHz and compare these structure with conventional MPA resonating at 2.4 GHz finally 82.83% miniaturization has been carried out by this DGS structure.


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REFERENCES [1] C.A balanis, “Antenna theory: Analysis and Design”,third edition, john Wiely & sons,2005, ISBN 812652422-8. [2] Anju Raj N, Rai Prakash Dwivedi, “High gain antenna with DGS for wireless application”, 2nd International Conference on Signal Processing and Integrated Networks (SPIN),pp. 29-24, 2015 [3] Partha Kumar Deb, Tamasi Moyra, Priyanka Bhowmik, “Return loss and bandwidth enhancement of microstrip patch antenna using defected ground structure”, 2nd International Conference on Signal Processing and Integrated Networks (SPIN),pp. 25-29, 2015 [4] Debatosh Guhaa,Manotosh Biswas and Yahia M.N, “Microstrip patch antenna with defected ground structure for cross polarization suppression,’’IEEE Antennas And Wireless Propagation Letters,Vol.4, pp. 455-458, 2005. [5] Debatosh Guha, Chandrakant Kumar and Surendra Pal, “Improved cross- polarization characteristics of circualr antenna employing arc-shaped defected ground structure”, IEEE Antennas And Wireless Propagation Letters,Vol.8, pp. 1367-1369, 2009. [6] Hanae Elftouth, Naima A.Touhami,Mohamed Aghoutane,Safae El Amrani, Antonio Tazon,and Mohamed Boussouis, “Minuaturize microstrip patch antenna with defected ground structure”,Progress In Elecromagnatic Research c,vol.55,pp. 25-33,2014. [7] Rajeswar Lal Dua, Himanshu Singh and Neha Gambhir, “2.45GHz Microstrip patch antenna with defected ground structure”, International Journal of Soft Computing And Engineering(IJSCE), ISNN:2231-2307, vol-1,pp. 262-265 jan 2012. [8] H. Weng, Y. C. Guo, X. W. Shi, and X. Q. Chen “An overview on defected ground structure”, Progress In Electromagnetic Research B, Vol. 7, pp.173–189, 2008 [9] Chirag Garg, Magndeep Kaur, “A review of defected ground structure in microwave design”, International Journal of Innovate Research In Electrical, Electronics, Instrumentation And Control Engineering, vol-2, Issue 3,march 2014. [10] Mrinmoy Chakraborty, Biswarup Rana, P.P Sarkar and Achinya DS. “Size reduction of microstrip patch antenna with slot and defected ground structure”, International Joural of Elecronics Engineering, pp.61-64’ 2012. [11] CST EM Simulation version 2012.


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Miniaturize Microstrip Patch Antenna with DGS Technology

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