Design Of UWB Band-notch Antenna And Broadband Dual-polarized Antenna

In the recent years,the wideband dual-polarized antenna provides an alternative solution for people's high demands on communication.Also,in order to avoid the interference between wide band and the frequency band which has been used in some modern wireless communication systems,the wideband antenna with band-notch characteristic has been studied widely.In this thesis,a broadband antenna with band-notch characteristics and a wideband polarization diversity patch antenna are studied.The main contents of this paper are as follows:1)A Ultra-Wideband differential antenna with band-notch performance is proposed.The proposed antenna has a compact size of 29.6 mm×33.6 mm×0.635 mm.Two symmetrical C-shaped conductive strips(TSCSCS)in the ground plane are used to change the impedance matching in the range of 6-7 GHz,and generate a notch band for the UWB antenna.The center frequency and the bandwidth of the notch band can be adjusted by changing the length and width of the TSCSCS,respectively.Also,the TSCSCS improves the gain.The results show that the proposed antenna exhibits a wider impedance bandwidth from 3.25 GHz to 10.8 GHz and the good rejection band from 5.9-7.25 GHz.Furthermore,in the whole operating band,the maximum gain can reach 5.53 dBi.2)Compact broadband dual-polarized aperture-coupled antenna is proposed.The total size is 15.5 mm×15.5 mm×4 mm.The antenna consists of four metal layers and three substrates.The top layer is substrate 1 with a disc patch,the middle layer is substrate 2 with a circular ring patch,and the top surface of the substrate 3 is ground plane with slots and two orthogonal feedlines on the bottom surface.To realize dual-polarization characteristic,two aperture-coupled feeding structures are arranged perpendicularly each other.By adding the disc parasitic patch,the bandwidth is broadened.And,by etching a rectangular slot with a tilt angle of 45°in the ground plane,the isolation in lower band is improved.The realized antenna has a bandwidth from 9.6 to 22.4 GHz.At the same time,the relative impedance bandwidth can reach 80%and the isolation is better than 15 dB.