IJCRR - vol 06 issue 07, April, 2014
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DESIGN AND EVALUATION OF HEXABAND MICROSTRIP ANTENNA
Author: Ambresh P. A., Sujata A. A., P. V. Hunagund
Abstract:This paper demonstrate simple, low cost Hexaband microstrip antenna with suitable feeding technique and dielectric substrate for applications in GHz frequency range. The optimum design parameters of the antenna are selected to achieve the improved bandwidth, high gain as well as best possible characteristics such as better radiation pattern, low SWR etc. Designed antenna achieved a bandwidth of 46 % resonating at six different bands between L to Ku band frequency ranges. Effect of slot on the patch is studied experimentally for enhancing the bandwidth. Designed antennas are suitable for L to Ku-band applications of wireless systems. Details of antenna design and results are discussed.
Keywords: Microstrip antenna, Quad band, Rhombus, VNA, Bandwidth.
Modern wireless communication system requires low profile, light weight, high gain and simple structure antennas to assure reliability, mobility and high efficiency characteristics. Hence microstrip antennas (MSAs) are most widely used due to their attractive features such as light weight, low volume, ease in fabrication and low cost . The demerits of the MSA are its narrow bandwidth and low gain and high SWR [1-2] which restricts their many useful applications. Different design configurations of microstrip antenna can give high gain, wide bandwidth and improved efficiency. With suitable feeding network which accumulates all of the induced voltages to feed into one point . The proper impedance matching throughout the corporate and series feeding array configurations provides high efficiency microstrip antenna . Power distribution among antenna elements can be modified by feed network. The feed network can also steer beam by introducing phase change . The desirable design parameters (dielectric material, height and frequency etc) are important because antenna performance depends on these parameters. Radiation performance can be improved by using proper design structures . The use of high permittivity substrates can also miniaturize microstrip antenna size . Thick substrates with lower range of dielectric offer better efficiency and wide bandwidth but it requires larger element size . Microstrip antenna with superconducting patch on uniaxial substrate gives high radiation efficiency and high gain in millimeter wave lengths . The width discontinuities in a microstrip patch reduces the length of resonating microstrip antenna and radiation efficiency .
Microstrip patch antennas consist of very thin metallic strip (patch) placed on ground plane where the thickness of the metallic strip is restricted by t<< λ0 and the height is restricted by 0.0003λ0 ≤ h ≤ 0.05λ0. The microstrip patch is designed so that its radiation pattern maximum and is normal to the patch. For a rectangular patch, the length L of the element is usually λ0/3? microstripline feed of length and width. (Lf x Wf) is (10.19 x 3.35 mm) while keeping other dimensions unchanged. At the tip of microstripline feed, a 50 ? coaxial SMA connector is used to feed the microwave power. Figure 2 shows the geometry of two slot rhombus shape (TSRSP) on patch. The dimension of TSRSP shown in Fig. 2 remains same as that of rectangular patch and feed line as shown in Fig.1, but two rhombus shaped slot which are placed horizontal on patch are etched on the patch plane of CRMA as shown in Fig. 2. Hence, this antenna is named as two slot rhombus shape patch (TSRSP). The dimensions of all the slots are taken in terms of λ0, where λ0 is the free space wavelength. The side length SL1 is 6.25mm equal on all sides. The horizontal and vertical slot lengths (L1 and L2) slots are 9.6 mm and 13.5 mm.
Authors thank Prof. Muralidhar Kulkarni, Head, Dept of E & CE, National Institute of Technology, Surathkal, Dakshin Kannada, Karnataka, India for providing an opportunity to use Agilent Technologies E8363B Network Analyzer. Authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors / editors / publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed.
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