COMPACT MULTI-BAND MICROSTRIP ANTENNA FOR WIRELESS APPLICATION

GRD Journals | Global Research and Development Journal for Engineering | International Conference on Innovations in Engineering and Technology (ICIET) - 2016 | July 2016

e-ISSN: 2455-5703

Compact Multi-Band Microstrip Antenna for Wireless Application A.Anandan Department of Electronics and Communication Engineering K.L.N College of Engineering Pottapalayam, Sivagangai 630 612 India Abstract A Multi-band rectangular micro strip antenna (RMSA) is proposed by a dual slot in the rectangular patch and a dual slot in the ground plane. Each open-ended slot in the single-slotted antenna is responsible to generate a wide impedance band that is shifted to lower frequencies by the effect of the ground slot. The dimension of the resultant antenna (12 * 8*1.5875 mm) reduces an average compactness to 53.73% when compared with a conventional unslotted rectangular micro strip patch antenna. The proposed antenna makes to operate in four bands of frequencies with large immunity to interference. The dual slots in the patch are responsible for two bands of frequencies and the open ended slot in the ground is responsible for two more bands in lower frequencies and the closed slot in the ground is responsible for the reduction of antenna size. The size and position of open ended slot is adjusted for the antenna to operate in two higher bands (5.306-5.59GHz and 5.784-5.990GHz) and open ended slot in ground is adjusted for lower band frequencies (2.578-3.052GHz and 3.382-3.688GHz).The obtained resonant frequencies can be used for WLAN and WiMAX. Keyword- Rectangular Micro Strip Antenna (RMSA), Wireless Application __________________________________________________________________________________________________

I. INTRODUCTION In recent years, the need for devices capable of operating in broadband is also driving research towards the design of multi-band radiating elements [1]. Micro strip monopole antennas have been widely used for wireless communications owing to their key advantages such as light weight, low profile and ease of fabrication [2]. Hence, micro strip antennas are promising for multi-band applications. Various techniques for design of dual-band WLAN antenna have been reported in [1]-[5]. In this paper, dual slots in the rectangular patch antenna is proposed for WLAN and WiMAX applications.

II. A SLOT IN PATCH AND GROUND OF RMSA The single rectangular open ended slot in the patch is used to increase the generated wave bandwidth. In order to achieve the slow wave effect to lower the resonant frequency, the ground plane area size is taken twice the size of patch. The signal return path is provided by the ground plane and the discontinuity in that path is provided by the closed ground slot which provides the way to achieve ‘slow wave effect’. These phenomena satisfy the infinite ground plane.

III. DUAL SLOTS IN PATCH WITH A GROUND SLOT IN RECTANGULAR MICROSTRIP ANTENNA Dual slots in the patch are responsible for generation of dual bands in such that the length and the position of slots are adjusted to vary the corresponding resonant frequency.

Fig. 1: Simulated reflection coefficient versus frequency plots of Antenna

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Compact Multi-Band Microstrip Antenna for Wireless Application (GRDJE / CONFERENCE / ICIET - 2016 / 058)

IV. DUAL SLOT IN PATCH AND GROUND OF RMSA There are four levels of slot formation in order to achieve the Multiband Rectangular Patch Antenna. The dimension of the RMSA is 12x8mm (Lp=12; Wp=8). The dimension of the FR4 epoxy substrate is 24 x 16 x 1.5875 mm and relative permittivity of 4.4.

The coaxial feed is given through an SMA connector (inner diameter and outer diameter are 1mm and 3.5mm) at 0.7 mm away from the lower edge of the RMSA.

Fig. 2: Front view of RMSA (Patch) Configuration of RMSA. Antenna .Lp=12mm, Wp=8mm, Lg=24 mm, Wg=16 mm, relative permittivity=4.4 and h=1.5875.

Optimized length L1=8 mm andlengthL2= 7.4 mm, g1=1.1 mm and g2=3.5mm. Thickness of slot 1= 0.6mm and slot2= 0.8mm.

Fig. 3: Back view of RMSA (Ground plane) Antenna dimensions are: Lg= 24 mm, Wg=16 mm, relative permittivity єr=4.4 and thickness of substrate h=1.5875. Length of closed slot t =14.8 mm and open slot t1 = 13.2mm, g3=6.5 mm, d= 4.6mm and g4 = 6.2mm. Slot Thickness b= 0.8 mm and b2= 0.6 mm.

Two rectangular open-ended slots and of nearly quarter-wave in length at patch are inserted separately inside the RMSA. It results in enhancement of the impedance bandwidths of single-slotted RMSAs. A rectangular slot of nearly quarter wave in length at the required center frequency is inserted in an optimized position inside the ground plane.

Fig. 4: Simulated reflection coefficient versus frequency plots

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Compact Multi-Band Microstrip Antenna for Wireless Application (GRDJE / CONFERENCE / ICIET - 2016 / 058)

In the final stage of modification, the open slot as per in the dimension of figure 2 is inserted in the ground plane, which generate two more band of frequencies.

Fig. 5: Fabricated antenna (Front view or patch)

Fig. 6: Fabricated antenna (Ground view)

Fig. 7: Fabricated antenna with soldered port Three antenna prototypes are built as shown in Fig. 5. The antennas are tested using vector network analyzer (VNA AgilentN9926A). Measured reflection coefficient with frequency plots of Antenna are illustrated in Fig. 6. Matching between the simulated and measured results is reasonably good.

Using FR4 substrate (dielectric constant 4.4 and height1.5875 mm), the required patch dimensions of a rectangular microstrip slotted antenna to resonate at four frequencies2.5 GHz, 3.6 GHz , 5.4 GHz and 5.8 GHz is 12mm * 8mm. Thus, the total of four bands and the size of antenna is reduced to 53.73%.

Fig. 8: Measured S11 (dB) characteristics of Proposed Antennas

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Compact Multi-Band Microstrip Antenna for Wireless Application (GRDJE / CONFERENCE / ICIET - 2016 / 058)

V. CONCLUSION A compact multi-band microstrip patch antenna is designed and analyzed. Primarily, four 10-dB impedance bands of the multi band are separately generated by two different designs of compact microstrip antennas with open and closed slotted ground-plane structures. Good agreement between the simulation results and measurement results is obtained. Overall, the design technique used for the dual-slotted in patch and ground multi-band RMSAs is successful for the application in WLAN band and resonant frequencies at2.5 GHz and 3.6GHz suits WiMAX. As the cognitive radio is emerging technology, the proposed antenna supports cognitive radio and the future work will be done based on it.

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