Mircostrip Patch Antenna with E Shaped Structure for S-Band Applications

Transcription

1 214 Mircostrip Patch Antenna with E Shaped Structure for S-Band Applications Nivedita Mishra #1 Department of Electronics and Communication Pranveer Singh Institute of Technology, Kanpur Abstract In this paper, the design parameters and results for a E- shaped rectangular microstrip patch antenna in IE3D 10.0 software is explained and the results obtained from the simulations are demonstrated. The microstrip patch design is achieved by using probe feed technique. In this paper, the double layer approach is used designing at 3.2mm height, the method to designing is using mirror image shape of patch on substrate(fr4) for improving return loss larger impedence bandwidth.any single structure having no mirror image cannot alter the performance of simple patch. The two E shaped structures are used in this work and result is in good agreement for parameter as return loss, VSWR with respect of frequency. These antennas has several application in the today s environment like in s band.in this paper work structure are used as modified rectangular microstirp patch antenna structures using mirror image. In order to evaluate the performance of proposed antenna, the antenna is simulated and analyzed or simulation tool IE3D. the analysis of antenna for physical parameters values as area of substrate, height of substrate,area of patch an ground has been done by varying one of them and achieving improve result of performance. Keywords Bandwidth, Rectangular Microstrip patches Antenna (RMPA), Return Loss, VSWR, Resonant frequency. 1. INTRODUCTION In the recent world,the demand for low weight,cheap,low profile and efficient antennas is increasing microstrip patch antenna are more popular for meeting these requirement in several applications. The main problem encountered with these such kind of patch antennas is high value of return loss and smaller impedence bandwidth but theses problem can be solved by using some new designing approaches. The research presented in this paper is primarily concerned with the impedance bandwidth, return loss and the voltage standing wave ratio of the antenna. All the rectangular microstrip patch antennas can be modelled on the easily available FR4 substrate. For designing the resonant antenna, microstrip patch antenna type is selected but it offers narrow impedance bandwidth. For covering the desired frequency band, the printed microstirp patch antenna type is selected which covers the almost entire band of the interest with the best return loss and the voltage standing wave ratio. The reason behind selecting the circle microstrip patch antenna type for replacing the rectangular microstrip patch antenna is an antenna will have a increases gain and impledance matching is increases. Aim of this thesis is to design appropriate microstrip patch antenna for larger impedance bandwidth, lower return loss and lesser VSWR for S band applications. Mirror image technique at substrate height 3.2 mm is to be investigated for patch antenna design at S band frequency range.the research presented here is primarily concerned with the impedance bandwidth, return loss and the voltage standing wave ratio of the antenna. All the rectangular microstrip patch antennas can be modeled on the easily available FR4 substrate. For designing the resonant antenna, microstrip patch antenna type is selected but it offers narrow impedance bandwidth. For covering the desired frequency band, the printed microstirp patch antenna type is selected which covers the almost entire band of the interest with the best return loss and the voltage standing wave ratio. 2. SIMULATION OF PROPOSED ANTENNA STRUCTURE The geometry of the proposed antenna is shown in fig1 (a). A rectangular patch of dimensions Lenght x Width separated from the ground plane using substrates a foam substrate (εr1) of thickness h1. The E-shape is located of the patch. The location of the slots on the patch can be specified by parameter width. The width and length of the slots are denoted by W and L. The rectangular patch is fed using 50Ω transmission probe. The software used to model and simulate the Microstrip patch antenna is Zeland 10.0 IE3D. IE3D is a full-wave electromagnetic simulator based on the method of moments. It analyzes three demensions and multilayer structures of general shapes. It has been widely used in the design of patch antennas, wire antennas, and other RF/wireless antennas. It can be used to calculate VSWR, return loss as well as band width.

2 Designing Microstrip Patch Antenna Step # 01: Calculation of the Width (W) The width of the Microstrip patch antenna is given as: 1 2 C 2 (1) 2 Fr ( ) r 1 2Fr r 1 Substituting c = 3.00e+008 m/s, ɛ r = 4.4 and fo = 2 GHz Step # 02: Calculation of Effective dielectric constant (εreff): The effective dielectric constant is: ff r1 r h 1 w Step # 03: Calculation of the Effective length ( Leff) The effective length is: C Leff (3) 2 f 0 reff ( 2) Substituting Eeff = 4.4, c = 3.00e+008 m/s and fo = 2 GH Step # 04: Calculation of the length extension (ΔL): W ref f h ( 4) L 0.412h W reff h Step # 05: Calculation of actual length of patch (L): The actual length is obtained by: L = Leff- 2ΔL (5) Step # 06: Calculation Of VSWR 1 VSWR (6) 1 Step # 07: Calculation of Return Loss RL 10log 10 db (7) By the Mathematic calculation Dielectric constant (εr): The dielectric material selected for design has dielectric constant of 4.4. A substrate with a high dielectric constant has been selected for reduces the dimensions of the antenna. Height of dielectric substrate (h): For the rectangular microstrip patch antenna to be used in cellular phones,wireless communication. it is essential that the antenna is not so bulky. Hence, the height of the dielectric substrate is 1.6mm. Cutting Width (w) and Length (L): The width and lenght was selected to be 5 mm and 10mm. 2.2 Design Methodology Literature servey Using the parameters ɛ r =4.4, tangent loss=0.02, h=1.6 mm for simple patch and 3.2mm for modified microstrip patch. Select specified length and width by help of mathematical formulas Design rectangular microstrip patch antenna Simulation of the antenna for band width and return loss help of ie3d software Optimization based on simulation results 3. DESIGNING OF RECTANGULAR MICROSTRIP PATCH ANTENNA The proposed antenna is shown in figure 1. The proposed dimension of L(lenght) & W(width) and is printed on a substrate of thickness h=1.6mm and relative permittivity =4.4. The print is etched on ground substrate. The antenna is fed by a 50- microstrip line. The basic rectangular microstrip line fed printed antenna design1 is shown in Figure 1.For exciting the operating frequency at around 2 GHz, the dimension of determined by Where c is the speed of light, is the effective relative permittivity and L is the length of Simple Rectangular Microstrip Patch Antenna Fed by Microstrip Line is Shown in Figure 1. A rectangular microstrip patch antenna is designed for the resonant frequency 2 GHz. The length of the patch is 35.44mm and its width is 45.65mm. The length of the microstrip line is 32.82mm which used for the feeding purpose. For the designing of this simple microstrip patch antenna we took a both sided copper PCB (printed circuit board). On the lower side of PCB copper coated field acts as the ground for this antenna and the on the upper side of the PCB we designed the different structure patch of giving dimensions. The whole geometry is simulated and raised practically using a dielectric substrate of height 1.6mm and having a dielectric constant 4.4mm. Loss tangent of the material is microstrip feeding technique is used for providing the feed to the antenna.

3 216 figure 1(a): Rectangular Microstrip Patch Antenna design this E-shape microstrip patch antenna is use mirror image designs technique for improving the performance. Any single structure having no mirror image can not alter the performance of simple microstrip patch antenna. The two E-shaped structures are used in this paper work and the results are in good agreement. E shape which can lead to a good impedance matching. Fig.2 shows the geometry of the proposed rectangular microstrip patch antenna respectively. As shown in Fig.2, the rectangular microstrip patch antenna has a compact dimension of mm x mm (Width x Lenght), designed on FR4 substrate with thickness of 3.2 mm and dielectric constant (εr) of 4.4. The antenna is fed by a microstrip line of 5 mm cut width and 10mm cut depth. The probe is used 50 Ω microstrip line printed on the partial grounded substrate with resonance frequency of 2GHz. The modified ground plane acts as an impedance matching element to control the impedance bandwidth of a rectangular microstrip patch antenna. Whereas Ws means width of antenna and Ls means length of antenna. By selecting these parameters to design, the proposed antenna can be tuned to operate in the 2 GHz frequency. The simulation results in this paper are obtained from Zeland IE3D 10.0 simulation software. Figure1(b): Simulation Results of Return Loss of Rectangular Microstrip Patch Antenna Fig2 Modified microstrip patch antenna1 Figure 1(C): VSWR for Simple Patch Antenna 3.1. Geometry & Designing In this paper, a small compact E shape rectangular microstrip patch antenna is presented. To 3.2 Return Loss & VSW The inset feed used is designed to have an inset cutting depth of 10mm, feed-line width of 5mm and feed path length of 36mm. A frequency of 2 GHz is selected and 151frequency points are selected over this range to obtain accurate simulated results. The center frequency is selected as the one at which the return loss is minimum. The bandwidth of the antenna can be said to be those range of frequencies

4 217 over which the RL is greater than -10 db (10 db corresponds to a VSWR of 1 which is an acceptable figure). Using IE3D, the optimum feed depth is found to be at Yo = 13.2mm where a RL of db is obtained. a centre frequency of 2 GHz is obtained. This technique is confirmed by the simulation result shown in Fig. 2. the effect of E slots to the antenna performance. From the graph, at frequency of 2 GHz, the S11 reaches -34dB and VSWR(voltage standing wave ratio) is The bandwidth enhancement is due to much more vertical electrical current achieved in the patch through the E shape resulting in much regular distribution of the magnetic current in the slots. Fig. shows the simulated current distribution of the proposed microstrip patch antenna at 2 GHz frequency. The simulation results, and patch antenna prototype was fabricated and tested. In this patch antenna prototype measurements are done by using a coaxial port which is soldered at the bottom edge of microstrip line in thr microstrip patch antenna. However, some differences in the simulated and measured results are measured and perform easyly. 3.3 simulated Results In order to evaluate the performance of the proposed rectangular microstrip patch antenna, the antenna is simulated through the simulation tool IE3D The analysis of the microstrip patch antenna for physical parameter values has been done by varying one of them parameter and keeping others as constant. It is carried out here to important study the flexibility in designing this of double layer patch antenna. Fig 2(b) simulation results of VSWR 2 Figure 2(c) Radiation Pattern of modified 1 rectangular microstrip patch antenna Fig2(a) simulation results of return loss 2 Figure 2(d) Smith chart for modified microstirp patch antenna 1

5 CONCLUSION The proposed antenna structure has been simulated using Zeland s IE3D simulator. Figures of obtained results show the variation of return loss with frequency for the simulated microstrip patch antenna. In the process, the resonant frequencies for which minimum return loss occurs for various designs after the successful simulation of the proposed antenna and then a comparison is done between various simulated responses. In the design of simple RMPA, it shows result of return loss which is-26db and VSWR is and modified rectangular microstrip patch antenna, it shows result of return loss which is -34db and VSWR is After this, it has been observed that design of modified antennas that gives as an improve results. It has been observed that inspired FR4 dielectric at 1.6 mm and 3.2mm used here for rectangular microstrip patch antenna reduced the return loss and enhance the impedance bandwidth significantly.the designing parameters as VSWR, return loss and impedance bandwidth are improved using mirror effect of paper designs. Aperture coupled Microstrip antenna for WLAN.IEEE Transaction on Antenna and Propagation, REFERENCES [1] Er nitin agarwal, dr.d.c.dhubkarya rectangular microstrip patch antenna using 2Ghz global journal (USA),february [2] Dheeraj Bhardwaj, Komal Sharma Dual band and Broadband Rectangular Patch Mircostrip Antenna with T Shaped Slot for WiMax Application International Journal of Engineering Research and Development,Volume 3, Issue 12,September [3] Bimal garg, Himanshu Srivastava, Prem Kumar, Micro-strip Patch Antenna with Parameters Improvement Using Symmetric Cylinder Shapes of Zero & Four Segments Meta-material Structure, International Journal of Computer Networks and Wireless Communications (IJCNWC), ISSN: , Vol.2, No.3, June [4] Ravishankar Tiwari, t shape microstrip patch antenna at 2.45ghz Journal of Research in Electrical and Electronics Engineering (ISTP-JREEE),2013. [5] F. Zhao, K. Xiao, W.-J. Feng, S.-L. Chai, and J.-J. Mao, Design and Manufacture of the Wide-Band Aperture-Coupled Stacked Microstrip Antenna, Progress in Electromagnetics Research C, Vol.7, Pg No , [6] Yoshiaki Kamiya,Wataru CHUJO and Masayuki FUJISE Design for Dual Frequency Microstrip Antenna using Annular Slot Aperture Coupling. Antenna and Propagation Society International Symposium, [7] S.M.Duffy and D.M.Pozar Circularly Polarized Aperture Coupled Antenna electronics letters Vol. 31 No. 16, 3rd August [8] Rashid. A Saeed, S.Khatun, Borhauddin, M.A. Khazani, Raina A Mokhtar Design of Single Fed