| In recent year, with the rapid development of modern communication technology, higher requirements of communication system are proposed. In order to meet the requirements of its development trend, the antennas with versatility get more attentions, such as the antenna of multiband, the antenna of multi-polarization. In this thesis, two new type of dual-polarized antennas are proposed:a dual-band dual-polarized antenna for WLAN and a broadband dual-polarized antenna. The main contents of this paper are as follows:1) A novel dual-band dual-polarized antenna for WLAN application with high isolation is proposed and implemented. The antenna achieves dual-band and dual-polarization by changing the dimensions of the patch and the cross slots in the ground plane. Also, a convex-shape radiation patch which is cut a slot in an angle achieves the dual-band. Meanwhile, a U-shaped aperture is etched in the feed line. As a result, the bandwidth and the port isolation of the antenna are further improved. The realized antenna can operate in the band from 2.2GHz to 2.46 GHz and from 5.31 GHz to 5.57 GHz. The antenna is simple, compact, and easy to process and integrate. It can apply to the WLAN band of mobile terminal.2) A novel broadband dual-polarized antenna is proposed and implemented. The radiating element of the antenna is a rectangular monopole. The antenna is fed by microstrip and CPW to realize the polarization diversity. In order to broaden the bandwidth, the monopole element is changed from a rectangular structure into a gradient one; meanwhile, in order to broaden the bandwidth of port 2, two rectangular apertures are etched in the ground plane. The realized antenna is compact with a total size of 50 mm × 50 mm × 1.6 mm. The measurement results show that the bandwidths of the two ports are from 2.2 GHz to 3.9 GHz and from 1.9 GHz to 4.4 GHz, respectively. The relative impedance bandwidths are 79.4% and 55.7%, respectively. The simulated result agrees quite well with the measured result. |
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