Reconfigurable Antenna For Application Specific Mobile Communications

Antenna with reconfigurable pattern as a new type of smart antenna has the advantage of miniaturization,high integration,wide band,and simple structure,which has great application prospect for the modern radar and cellular mobile communication system.In this paper,a 1.4GHz pattern reconfigurable microstrip antenna and a k-band pattern reconfigurable SIW horn antenna have been designed.The dissertation is organized as follows:Firstly,based on the principle of Yagi-Uda microstrip,a wide band pattern reconfigurable microstrip antenna has been designed,which consists a coaxial-fed U-slot patch and two identical parasitic patches placed symmetrically around the middle patch,where the each parasitic patch loads one varactor.The impedance bandwidth can be enlarged 3 times by the U-slot structure in the middle patch compared to general pacth,and the beamwidth can be tunned from 60° to 130° or the main lobe direction can continuously scan from-20° to 20° in the yoz plane by the DC voltage of the varactor diodes on the two parasitic patches.In this way,a wide impandance bandwidth and wide beamwidth tunning range can be realized.Next,a k-band single-pole single-throw(SPST)switch applicated in substrate integrated waveguide(SIW)and a switchable four ports substrate integrated waveguide feeding network using the SPST switch have been designed.By electrically controlling the SPST switch of the four ports,the feeding network can transmit the electromagnetic wave to any port.The structure of the four ports feeding network retains the SIW advantages of low profile,ease of integration,wide bandwidth,high isolation,low insertion loss,simple structure and so on.Finally,a k-band main lobe direction reconfigurable antenna,which is used the above-mentioned four ports switchable feeding network,is designed,fabricated and measured.The proposed antenna can realize 0°-360° beam scanning on horizontal plane.Simulation and measurement results show that,the proposed reconfigurable antenna has advantages of wide band,low profile,high cross polarization isolation.