Design Of Polarization-agile Phased Array Antenna With Integrated Structure Of Phase Shifter And Power Divider

In wireless communication, target recognition, polarization diversity and other fields, the use of signal’s polarization information play an important role in the communication capacity expansion, improvement of immunity, reduction of the multipath attenuation, respectively. In order to transform and receive the multiplied-polarization signals in the mentioned applications, the antenna is required to have the ability to switch between different polarizations quickly, which is called polarization-agile antenna. In additions, the polarization-agile antennas can be used to constitute a phased array to improve the gain and to realize phased scanning.In the design of polarization-agile antenna, the polarization-agile antennas is required to have high polarization purity, the feeding network is required to have low insertion loss and the low complexity of the whole system is also required. To meet the requirements above, based on the model of the novel power divider and phase shifter structure, a novel electronic-control polarization-agile antenna which can realize dual circular polarization agility and a novel polarization-agile phased array are presented. Compared with the traditional polarization-agile antenna, the presented structure has higher polarization purity, lower insertion loss and wider bandwidth. Besides, compared with the traditional polarization-agile phased array antenna which has independent power dividers and phase shifters, the presented work has lower complexity and insertion loss.Firstly, based on the structure of the ±90 degree power-divider-phase-shifter structure, a novel electronic-control dual circular polarization-agile antenna polarization agility antenna is realized. Then, based on two kinds of 4 bits power-divider -phase-shifter structures which can realize 0°,±22.5°,±45° ±67.5° and 0°, ±45°, ±67.5°, ±90°, ±135° respectively, a feeding network for phased array is designed. Finally, a 2x2 polarization-agility phased array is composed with the presented polarization-agility antenna unit and the presented network base on power-divider-phase-shifter structure.