Design and Implementation of Microstrip PatchAntenna Array George Casu1, Cătălin Moraru2, Andrei Kovacs (Corresponding author)1* Military Technical Academy, Faculty of Electronics and Informatics, Bucharest, Romania *Corresponding author (E-mail:
[email protected]) Abstract – This paper refers to a detailed analysis on the design and implementation of 4x1 and 8x1 microstrip patch antenna (array) of given specifications using IE3D software and a dielectric material FR4 with dielectric substrate permittivity of 4.28, tangent loss of 0.002 and height of 1.6 mm. The microstrip patch antenna array is designed for WLAN applications, at an operating frequency of 2.4 GHz with microstrip line feed and power dividers. Keywords - microstrip antenna; microstrip antenna arrays; antenna; simulation; microstrip line feed. are usually in the range of 2.2<Er<12 . The most popular models for the analysis of microstrip patch antennas are the transmission line model, cavity model and full wave model. The transmission line model is the simplest of all and it gives good physical insight but it is less accurate [4]. I. INTRODUCTION As an interface between the transmitter/receiver and the propagation media, antenna is an essential part of any wireless communication (satellites, radars, aviation, medical applications, ground penetrating radar etc.). [1] [2] [3] The key features of a microstrip patch antenna are ease of construction, light weight, low cost, the antenna can take an arbitrary form of the space that occupies if the substrate is flexible and the production process has a highly level of integration, the same circuit can include the microstrip antenna and also the feeds [3] . These advantages of microstrip antennas make them popular in many wireless communication applications such as telemetry and communications, aviation, naval communications, automatic guidance of intelligent weaponry, radar, GPS systems. The disadvantages of microstrip patch antennas are: narrow frequency band with low efficiency, feeds have high losses and disability to operate at high power levels of waveguide [3] [4]. Therefore, reliable solutions must be found to increase bandwidth and to achieve higher gain. Figure 1. Geometry of microstrip patch antenna The width of the microstrip patch antenna was computed with the following equation [6][7]: 38 where c is the speed of light (3x108 m/s), fr is the operating frequency of 2.4 GHz and Er is the dielectric permittivity of 4.28. The length of microstrip patch antenna is given by the following equations: 1 978-1-4799-2385-4/14/$31.00 ©2014 IEEE 12 3.979 (2) where Ereff is the effective dielectric constant and h is the thickness of the dielectric substrate. II. MICROSTRIP ANTENNA DESIGN In this paper, the microstrip patch antenna array ( 4x1, 8x1 ) has been designed to operate at a center frequency of 2.4 GHz with an input impedance of 50 Ω using a dielectric material FR4 with r = 4.28, tangent loss tgδ=0.002 and thickness (h) of 1.6 mm. For microstrip antennas, the dielectric constants (1) . 0.412 31 . . . . 7.417 (3) 10 (4) In the equation above ΔL stands for length extension. 39 . (6) (7) 1 0.063 (10) Figure 5. the actual length of the microstrip patch antenna is given by: 2 30 (5) III. Taking into consideration that one section of the power divider 2 . To compute the width w of the feed for an impedance Z0 of 50 Ω the following equations were used: 0.Therefore. EXPERIMENTAL RESULTS For designing the microstrip antenna and the microstrip antenna arrays it has been used Zealand IE3D Software. 3D directivity characteristic for microstrip antenna . Figure 4. to achieve impedance adaptation is equal with with the 50 Ω line feed the impedance of the power divider was calculated : 70. Top view of antenna The effective wave length is given by: 0. 2 1 1 31 (8) Figure 3.123 (12) Figure 6.23 .64 mm.711 (9) Therefore. Polar and cartesian plot for the directivity characteristic To compute the distance between the feed and the lower side of the antenna for a given impedance Zin of 50 Ω it was used the equation: 50 300 (11) √ 9. The designed antenna and its current distribution Furthermore. for an impedance of 70 Ω the following value of w was obtained: w=1. for achieving impedance adaptation the width of the power divider was also computed. Frequency characteristic (S11 parameter) Figure 2. Concerning the main difference between the microstrip patch antenna and the array is that the directive characteristic increases in directivity with the number of antennas.For the phased array with 4 antennas.375 GHz was obtained. a 28 degrees orientation of the maximum radiation pattern was achieved by modifying the length of the feeds of the array comparing with the sinfazic array. S11 parameter and VSWR Figure 8. For implementing the microstrip patch antenna the dielectric material FR4 was used [6]. Current distribution of the 8x1 array Figure 7. Polar and cartesian plot for the directivity characteristic Concerning the phased array [8] [9]. Figure 11. where all the elements are fed with the same amplitude and phase [8]. Implemented sinfazic array . Polar and cartesian plot for the directivity characteristic Figure 9. Figure 14. a center operating frequency of 2. Designed array and its current distribution Figure 12. Designed 8x1 array Figure 15. Implemented microstrip patch antenna Figure 10. S11 parameter and VSWR Figure 13. Moreover. Design of Reconfigurable Multiband Microstrip Patch Antenna for Wireless Communication. ISSN. and Ioan Nicolaescu. Issue 9. therefore. 2010 On page(s): 1 . In practice..2. Volume-1. Issue 1. Nicolaescu. Figure 16. the sinfazic network (-18 dB). Smart antennas for wireless communications systems. TELSIKS 2001. Microstrip Antenna Array for WiMAX & WLAN Applications. Progress in Electromagnetics Research Symposium Proceedings. ``Subsurface imaging using measured near-field antenna footprints''. 2013. on the Oy axis the power level (W) is represented and on the Ox axis the orientation of the directivity feature ( º ) is represented. the impedance adaptation between the antenna and the feed line was achieved. “Antene Microstrip – Îndrumar de proiectare”. Vol. The measured and simulated directive characteristics are almost identical and confirms us that a microstrip patch antenna has a larger directive characteristic than the array.A. the measured S11 parameters are almost the same as the simulated parameters: the antenna (-16 dB). Md. Print ISBN: 9781-61284-998-0. where it is applied the group directive function. 2. IJMER. 20th International Conference on Applied Electromagnetics and Communications-ICECom 2010. a horn antenna used as reference and a power measurement tool . F. pp. Volume 2. Design and Performance Analysis of Microstrip Array Antenna. Volume 2. Vol. Al-Amin Chowdhury. Md. Design and Performance Analysis with Optimum Param. REFERENCES [1] [2] Figure. September 2013. Croatia. 2001. . sinfazic array in the horizontal plane The results obtained in simulation proved that the 3dB bandwidth of the microstrip patch antenna is smaller than the 3dB bandwidth of the array (90 MHz and 140 MHz). Nicolaescu Ioan. Measured S11 parameter of the array [6] [7] [8] [9] Figure 20. Koen W. 2.682 vol.2). Losif. Muhammad Mahfuzul Alam. Null steering arrays. IJACSA. Nilima Bodhaye. The horn antenna used as reference 250 200 150 Antena Retea simfazica 100 50 0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 Figure 17. Issue-1. 2001 Page(s):679 . Cable and Broadcasting Service. No. 4. 18 Measured S11 parameter of the antenna [3] [4] [5] Figure 19. Vol. IJEIT. ISBN 978-953-6037-58-2 Issue Date: 20-23 Sept. Shihabul Islam. CONCLUSIONS The directive characteristic of these microstrip patch antennas were measured using a power generator. Peter M. the antenna doesn’t contain secondary lobes comparing with the array which means that there aren’t power losses. Krishan Kumar Sherdia. Number 1. Kamal Hosain.. 2008. meaning that there weren’t very high power losses. Richa Sharma. For X-band Apps. IJARCCE. Mustafizur Rahman Sonchoy. 5th International Conference on Telecommunications in Modern Satellite. 19-21 Sept. van den Berg.4 Dubrovnik. Dubrovnik.D. 2011. Facultatea de Electronică i Telecomunica ii. unpublished. Design of Microstrip Patch Antenna Array for WLAN Application. Devashri Marotkar. S11 Smith Chart of the antenna and the array Priya Upadhyay. Shruti Singh Roy. 31-37. Concerning VSWR. august 2009 Page(s): 1837 – 1842. Vivek Sharma. Near Surface Geophysics. Stoica Dan.IV. 2. Directive characteristic of the antenna vs. Osman Goni. I. September 20-23. February 2004. ISSN: 1569-4445. the values obtained in each case were between (1. van Dongen. Ion Bogdan. Naresh Kumar Poonia. In the figure above. July 2012. Tanvir Ishtaique-ul Huque. pp 1-4. The S11 parameter of the antenna (-12 dB) is greater than the S11 parameter of the sinfazic network (-18 dB) and the phased network (-14 dB).