Comparative Analysis of FR4 and RT-duroid Materials Antenna for Wireless Application

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1 Vol. 2, No. 2, 2016, 1-10 Comparative Analysis of FR4 and RT-duroid Materials Antenna for Wireless Application a G B Waghmare, b A J Nadaf c P M Korake and * M K Bhanarkar a,b,c, * Communications Research Laboratory Department of Electronics, Shivaji University, Kolhapur, India Corresponding author, Professor, m.k.bhanarkar@ieee.org; mkb_eln@unishivaji.ac.in a Ph.D., Student, elnganesh@gmail.com b Ph.D. Student, onlineashpakv@rediffmail.com c Ph.D. Student, korake.prakash@gmail.com ABSTRACT: The study of the effect of dielectric material is carried out in this paper. FR4 with 4.4 and RT-duroid with 2.2 as a dielectric permittivity are considered for the comparative study. The Y- shaped antenna is designed and simulated with IE3D method of moment software. A fundamental parameter like return loss, VSWR, gain, radiation pattern, radiation efficiency is analyzed. Y-shaped patch antenna based on FR4 and RT-duroid as materials have been optimized good characteristics at 2.25 GHz and 2.4 GHz respectively. KEYWORDS: Efficiency; dielectrics; antenna; wireless application 1. INTRODUCTION The dielectric materials play important role in antenna manufacturing process. In antenna especially in integrated antenna, the dielectric constant varies between 2.2 to 12. The thick substrate with low dielectric constant gives good performance and provides better efficiency, larger bandwidth, but large antenna element. While thin substrate with higher dielectric constant provides smaller element size however because of their greater losses they are less efficient and have relative smaller bandwidth [1]. It has been analyzed in [3] that performance of antenna improves when the value of dielectric constant reduces. Triangular shaped patch antenna for ISM frequency band on the FR4 substrate is designed in [4] which shows excellent broadband performance. In [5] the RT-duroid based X-band frequency 10 GHz and Ku- band frequency 13GHz antenna is designed which improves the performance of the antenna, and it has become a necessity for many applications in recent wireless communications, such as Radar, Microwave and space communication. Microstrip patch antenna for ISM band is fabricated and tested in [6] on FR4 with 4.4 dielectric constant, which is applicable for 1

2 Radar and also suitable for portable equipment. 2. ANTENNA DESIGN The Y-shaped patch antenna is chosen for the validation of dielectric material performance. By keeping size and height of the dielectric material constant the results are analyzed. The proposed design of novel Y-shaped patch antenna shown in Figure1. Length and width of dielectric material are 100x100mm, with a thickness of 1.6. The Y shape antenna size not same at every patch actually this antenna is made of off reducing the antenna and branches size at every iteration. The microstrip attaches to the antenna is taken as 6 mm in width and 50 mm in length. Another two antenna branches are made by reducing the strip in its half size that is 3 mm in length and 25 mm in width. Further, the same reducing criteria apply for remaining four branches with 1.5 mm width and 12.5 mm in length final design in shown in Figure 2. Figure 1 Proposed Y shape antenna Figure 2 Simulated Y shape antenna 3. RESULTS Return loss shown in Figure 3 and 4 shows that the antenna is resonating in between 2 GHz and 3 GHz. Figure 3 shows the return loss of -32dB at 2.25 GHz for FR4 dielectric material comparatively Figure 4 shows return loss of db at 2.4 GHz. In fact both the results shows good return loss values however RT-duroid provide return loss at 2.4 GHz 2

3 which applicable for ISM band. Figure 3 Return loss for FR4 Figure 4 Return loss for RT-duroid VSWR is quite similar whereas in both the cases, which conclude the values less than 2 as per discussed in [2] the values for FR4 and RT-duroid are and also less than 2. Antenna gets back less voltage towards the source and receive the maximum. Figure 5 VSWR for FR4 Figure 6 VSWR for RT-duroid The impedance of port must match to antenna impedance called port matching characteristics or Z parameter, and the value in this case of the antenna is 50 ohm. In Figure 7 and 8, the impedance result displays near about 50-ohm impedance at respective frequencies. 3

4 Figure 7 Z parameter for FR4 Figure 8 Z parameter for RT-duroid Smith chart display antenna matching characteristics, for both of the dielectric material the impedance matched well and also put real values at 2.25 GHz and at 2.4 GHz. Figure 9 Smith chart for FR4 Figure 10 Smith chart for RT-duroid In transmitting antenna the gain specifies how well the antenna converts input power into radio waves as a function of direction, however at the receiving terminal gain describes how well the antenna converts radio waves from a specific direction into electrical power. When no direction is specified the gain is understood to refer to the peak value of the gain. The maximum gain of the antenna at 0 db is shown in Figure 11 and 12 4

5 for FR4 and RT- duroid respectively. Figure 11 Elevation pattern gain for FR4 Figure 12 Elevation pattern gain for RT-duroid A plot of the gain as a function of direction is called radiation pattern. Radiation pattern for FR4 and RT-duroid material shows bidirectional radiation pattern in Figure 13 and 14. 5

6 Figure 13 Radiation pattern for FR4 Figure 14 Radiation pattern for RT-duroid The antennas gain generally define as the ratio of power produce by the antenna from a far field source on the antennas beam axis to the power produced by the hypothetical lossless isotropic antenna. The ratio of total field gain Vs. the frequency of antenna in Figure 15 and 16, have the good positive gain at 2.25 GHz and at 2.4 GHz for FR4 and RT-duroid. Figure 15 Radiation pattern for FR4 6

7 Figure 16 Radiation pattern for RT-duroid Directivity is the power radiated by an antenna in a particular direction as a function of space co-ordinates, or it is defined as power radiated in a particular direction to the power radiated by an isotropic antenna. Figure 17 Directivity of FR4 7

8 Figure 18 Directivity of RT-duroid The maximum directivity is achieved by RT-duroid material as compared to FR4 material. Directivity for FR4 at 8 GHz will give 6.5 dbi while for RT-duroid it gives 7.5 dbi in [2]. Antenna efficiency is the ratio of total power radiated by an antenna to the net power accepted by the antenna. It is expressed in percentage and sometimes in db also. Figure 19 Efficiency of FR4 8

9 Figure 20 Efficiency of RT-duroid For high efficient antenna most of the power presented at the input radiated away and for low efficient antenna, most of the power absorbed as losses within antenna or reflected towards source due to impedance mismatch. The antenna efficiency for FR4 material specifies 59% efficiency while RT-duroid has 74% efficiency. Table 1 FR4 and RT-duroid for Y-shaped antenna at second iteration Dielectric Material Resonance Frequency GHz Return loss db Impedance ohm Gain dbi Directivity db Efficiency % FR RT-duroid An efficiency for FR4 in the present paper is 59 which is greater as comparedd to RF4 efficiency mentioned in [2], also the RT-duroid efficiency is little lower than efficiency mentioned in [2]. 4. CONCLUSION The comparative study on FR4 and RT-duroid dielectric material for patch antenna provides good results. Antenna performs well for FR4 in terms of maximum return loss, good impedance matching, higher gain, directivity, and efficiency. FR4 based fractal antenna further used for WI-FI, WLAN, Bluetooth and other wireless applications. On the 9

10 other hand, RT-duroid has frequency shift at 2.4 GHz as a result of changing dielectric constant. Over all RT-duroid material uses in higher frequency applications because of its higher efficiency, even though FR4 antenna results in the better electrical parameter. The results show the antenna resonates at 2.4 ISM band so that we can use it for biomedical applications. ACKNOWLEDGEMENT Authors are thankful to administration Shivaji University, Kolhapur, India to provide a facility for this research. REFERENCES 1. C A Balanis (2005), Antenna theory analysis and design', A John Wiley & Sons, Inc., Publication. Third Edition, Page no Anzar Khan and Rajesh Nema (2012), 'Analysis of five different dielectric substrates on microstrip patch antenna', International journal of computer applications, Vol. 55, No.18. Page no Sohaib Abbas Zaidi and M R Tripathy (2014), 'Design and simulation-based study of microstrip E- shaped patch antenna using different substrate materials', Advance in electronic and electric engineering, Vol. 4, No. 6. Page no Sharma L N, Das S and Gogoi A K (2005), 'ISM band triangular patch antenna on FR4 substrate with U pattern slots', INDICON, Annual IEEE, 11-13, Page no Neenansha Jain, Rajesh Nema, Anubhuti Khare and Puran Gour (2011), 'Dual band E-shape micro strip patch antenna on RT-duroid 5880 substrate for pervasive wireless communication', International journal of computer science and information technologies, Vol. 2 (3), Page no Waghmare G B and Bhanarkar M K (2014), 'Microstrip patch antenna for ISM band applications', International journal on recent and innovation trends in computing and communications, Vol. 2, Issue: 7, ISSN: , Page no