Research On Pattern And Polarized Reconfigurable Antenna For Terminal

With the development of wireless communication,the requirements on antennas are getting higher and higher.The reconfigurable antenna is proposed to meet the requirements of the wireless communication system for the antenna.The pattern reconfigurable antenna has the advantages of improving the security of the system,beam scanning,and size reduction of the antenna.Polarization reconfigurable antenna changes the polarization state according to the surrounding environment in real time,greatly reducing the polarization mismatch,enhancing the system's ability to resist noise and improve the transmission efficiency of the system.Pattern and polarization reconfigurable antenna are achieved by adding a parasitic layer to the antenna.PIN diodes is loaded between the parasitic patches.The coupling current path is changed by controling the state of PIN diodes.The antenna has nine beam pointing in the three-dimensional space,and could achieve two orthogonal linear polarization wave.At the same time,the detection circuit and control circuit was designed,and the control circuit was integrated with the antenna.Two low-noise amplifier were added before the detection circuit,which achieves signal amplification of about 30 dB.The detected voltage was used by the microcontroller to compare the signal power of the beam state and select the largest,and control the microcontroller output then maintain this state.The antenna can switch their own beam states based on real-time environmental changes.This paper presents a beam switchable antenna that enables four different beam directions.Quasi-yagi antenna is used as antenna unit.The four beam direction is realized by butler matrix feeding network,and the detection circuit and control circuit is designed to make the antenna system switch the beam direction automatically with the change of the surrounding signal.