Research And Design On Reduce-size Dual-polarized Antenna And Reconfigurable Antenna

Microstrip compact dual-polarized antenna and microstrip reconfigurable antenna are themain contents of this thesis. With the rapid development of various wireless systems, people havegreater demand of antennas. Dual-polarized antenna can achieve polarization diversity whichmakes the size of the equipment smaller. Frequency reconfigurable antenna can work flexibly, theoperating frequency of the reconfigurable antenna can be changed according to the changes of theenvironment. Reconfigurable antenna can reduce the size and weight of the wireless system.The main research work are as follows:(1)Two compact dual-polarized antennas fed by coaxial are proposed. The antennas use a setof slits and slots to increase the length of the antenna surface current, which can reduce the area ofthe antenna.. The proposed antennas are simulated by using EM simulator. Two prototypes arefabricated and measured, and the measurement results and simulation results are consistent. Thefirst dual-polarized antenna is40%smaller compared to a traditional dual-polarized square patchwithout slots at the same frequency. The isolation between the two ports is less than-34dB inbandwidth(S11≤-10dB). The second dual-polarized antenna is51%smaller and the isolationbetween the two ports is less than-31dB in bandwidth(S11≤-10dB).(2)A compact dual-polarized antennas fed by microstrip is proposed. A prototype is fabricatedand measured, the measurement results show that the proposed antenna is46%smaller and theisolation between the two ports is less than-28dB in bandwidth(S11≤-10dB).To change the feedstructure of the proposed antenna, a circularly polarized antenna is achieved.(3)A frequency reconfigurable antenna is proposed. The antenna can operate at differentfrequency by controlling8switches on the slot rings. On and off state of the switchs are able toinfluence the current distribution of the antenna surface. The antenna is simulated by using EMsimulator. The simulation results show that the frequency reconfigurable antenna can work at1.46GHz,1.52GHz,2.14GHz,2.25GHz and3.4GHz with the similar pattern..