ISSN ONLINE(2278-8875) PRINT (2320-3765)
Jigar M. Patel1, Shobhit K. Patel2, Falgun N. Thakkar3
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An antenna is the most important element of any wireless communication. This paper is highly focused on the multiband application of the Microstrip Patch Antenna. In first phase the S – shaped Multiband Microstrip Patch antenna is simulated and analyzed. Comparative analysis between Common S-shaped Multiband Microstrip Patch Antenna, Defected Ground Structure S-shaped Multiband Microstrip Patch Antenna using Complementary Split Ring Resonator and S – shaped Multiband Microstrip Patch Antenna using Metamaterial is shown in this paper. The proposed antenna is designed for various multiple applications such as Bluetooth, L and S band applications which are used in Medical Application and ISM Application, in the operating range 1-5 GHz. Here S-shaped meandered patch of dimension 50×50 mm2 is analyzed. Design results of VSWR, Return loss S11, Total Gain plot and Total Directivity Plot are shown in this paper. Design results are obtained by a HFSS (High Frequency Structure Simulator) which is used for simulating microwave passive components.
Keywords |
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Microstrip, Multiband, S-Shaped, DGS, CSRR. | ||||||||
INTRODUCTION |
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A microstrip antenna contains very extensive applications in recent times because of its light weight, small size, easy reproduction and integration ability with the circuitry [1-10]. The rapid development of electronics and wireless communications led to great demand for wireless devices that can operate at different standards such as the universal mobile telecommunications system UMTS, Bluetooth, wireless local-area network (WLAN) and also satellite communications. However, frequency steering capability shows that it is difficult to keep the frequency fixed without any changes [11]. In addition, compact small size is a demand factor for several applications as mobile devices. These two requirements have triggered research on the design of compact and single or multiband antennas operation [12]. Microstrip patch antennas are widely used because of their many merits, such as the low profile, light weight and conformity. However, patch antennas have a main disadvantage: narrow bandwidth. Researchers have made many efforts to overcome this problem and many configurations have been presented to extend the bandwidth [13]. | ||||||||
Microstrip patch antennas are widely used in wireless devices and other compact sizes with multiband antenna operation. The techniques for reducing the size of Microstrip patch antenna are reported extensively and include capacitive loading [1], LC resonator [2], meander configuration [9, 10]; however, these techniques usually trade off the antenna bandwidth or antenna efficiency to achieve the reduction in antenna size. Different techniques [14] for creating multiband Microstrip patch antennas with metamaterial have been published, such as adding SRR elements in substrate [15] to reduce the size of the patch antenna. There is a tradeoff between number of operating bands and antenna size. Reconfigurable antennas represent a recent innovation in antenna design that changes from classical fixed-form, fixedfunction antennas to modifiable structures that can be adapted to fit the requirements of a time varying system. Advances in microwave semiconductor technologies enabled the use of compact, ultra-high quality RF and microwave switches in novel aspects of antenna design. | ||||||||
The S-shaped Patch antenna [16] was designed and simulated which gave only three bands. Now to enhance the bands, Defected Ground Structure with Complementary Split Ring Resonator (CSRR) is used in this proposed design. | ||||||||
Recently a defected ground structure (DGS) [17] have been introduced, DGS is realized by etching off a simple shape in the ground plane, depending on the shape and dimensions of the defect, the shielded current distribution in the ground plane is disturbed, resulting a controlled excitation and propagation of the electromagnetic waves through the substrate layer. The shape of the defect may be changed from the simple shape to the complicated shape for the better performance. | ||||||||
Very recently, complementary split-ring resonator (CSRR), which is the negative image of split-ring resonators (SRR) [16], has been reported by some authors. It has been demonstrated that CSRR etched in the ground plane or in the conductor strip of planar transmission media provides a negative effective permittivity to the structure. CSRR has been successfully applied to the narrow band filters and diplexers with compact dimensions. | ||||||||
Recently Metamaterial is the one of the artificial material which is used as a substrate. It has two parameters: permittivity and permeability. When both material parameters possess negative real parts, such double negative (DNG) media can support wave propagation and exhibit the peculiar phenomenon of negative refraction, while media with a single-negative (SNG) parameter, such as plasmonic media support evanescent wave. | ||||||||
ANTENNA DESIGN |
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This section, we will introduce the design of our antenna. First the conventional patch length and width is designed. After designing the patch, we have taken out two slits from the patch to make it S-shape patch. Basic length and width is designed with the use of following equations. | ||||||||
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Width of the patch can be designed using the equation (1), here f0 is the center frequency, εr is relative permittivity and c is speed of light. | ||||||||
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Length of the patch can be designed by using the equations (1-5). Here t is the thickness of substrate. Using these equations we have designed length and width of conventional patch here. | ||||||||
Here we designed square patch so length and width are same and it is 50 mm, so a square patch is 50×50 mm2 over here which is shown in Figure 1. We have taken out two slits from the patch to make it S-shape and to improve the results as shown in figure. The slits taken out have dimension of 30×10mm2. The top view and side view of the design is shown in Figure 1(a) and 1(b) respectively. | ||||||||
Table 1 shows details about the material. Patch is of copper material. Substrate is of FR4 epoxy material with ε=4.4. The base material is also of copper. | ||||||||
SIMULATION RESULTS AND DISCUSSION |
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For simulation we used HFSS 11 of Ansoft, which is very good simulator for RF antennas. After simulating the design the result we got is as follows. | ||||||||
Figure 2 shows the Return Loss (S11) plot of the design and Table 2 shows values of Return Loss (S11) in dB for different bands with their frequency. The minimum return loss which we are getting for this design is -38 dB for the second band centered around 2.47 GHz. | ||||||||
Figure 3 shows the voltage standing wave ratio (VSWR) plot of the design and Table 3 shows values of VSWR for different band with frequencies. For the entire band VSWR is less than 2 and lowest VSWR for the design is 1.02 for the second band centered around 2.47 GHz. | ||||||||
The comparative analysis between simple S-shaped Multiband Microstrip Patch Antenna, Defected Ground Structure S – shaped Multiband Microstrip Patch Antenna using Complementary Split Ring Resonator and S – shaped Multiband Microstrip Patch Antenna using Metamaterial is shown in Table 4. | ||||||||
CONCLUSION |
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Microstrip antennas have become a rapidly growing area of research. Their potential applications are limitless, because of their light weight, compact size, and ease of manufacturing. In comparative analysis, DGS S-shaped Microstrip Patch Antenna using CSRR and S-shaped Microstrip Patch Antenna using Metamaterial have give more band than the proposed simple S-shaped Microstrip Patch Antenna. The modeling and iterative simulations are carried out at center frequency of 2.5 GHz. The result indicates the multiband so the antenna can used for L Band and S Band Applications. Further design can be modified to have multiband for other applications in C Band, X Band and other bands. It can be also used for L and S band applications which are used in Medical Application, Bluetooth application and ISM Application. The results are in very good agreement with the industry and standard published antenna-requirements with respect to ease of fabrication, compactness and volume miniaturization compared to other antennas so far designed for similar applications. | ||||||||
Tables at a glance |
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Figures at a glance |
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References |
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