International Journal of Computer Science Issues

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Certain applications such as RFID, on body sensors network, microwave systems usually require good matching impedance, high gain and large bandwidth for their antennas. The aperture coupled antenna is one candidate that can provide high gain large bandwidth and little packaging. Thus, it would be of interest to enhance the characteristics of a singly-fed aperture antenna used for Zigbee application. In this paper, we are presenting a new design of aperture coupled rectangular patch antenna operating at 2.45 GHz ISM-band frequency. The objective of this design is not limited to the improvement of the impedance bandwidth but also to better the coupling involved. The cross-polarisation (X-pol), the backward radiation and the half-power beam width in two orthogonal planes are also examined. The proposed design is based on a new aperture coupling technique in which two slots are fed by a microstrip line and coupled to a parasitic patch radiator etched on the opposite side from the slots. The matching impedance for a conventional aperture coupled microstrip antenna is obtained by the adjustment of the dimension of the slot and the feeding line. Here, the distance separating the slots is employed to control the coupling and modifying the input impedance of the antenna. Therefore, accurate matching impedance is reached with a good radiation pattern.