Research On Dual-Band Dual-Polarized High-Gain Array Antenna

With the rapid development of the Direct Broadcasting Satellite technology,the receiving antenna for the broadcasting video signals of the satellite is moving to low cost,miniaturization,planarity,multifunction.The dual-frequency dual-polarized planar antenna,which has the many good characteristics such as small size,light weight,high bandwidth efficiency and large communication capacity and so on,has won the extensive attention and research.After studying microstrip antenna,which is the basic type of the planar antenna receiving the broadcasting video satellite signals,about its fundamental theory,dual-frequency technology,dual-polarization technology and array technology,a Ku-band dual-band dual-polarization high-gain planar array with new structure is proposed according to the research of single-layer dual-band dual-polarized wide slot microstrip antenna.The main research contents and results are summarized as follows:1.With the research on the multi-resonant feature of wide-slot structure,a single-layer dual-band dual-polarization wide-slot microstrip antenna is proposed.The dual-polarization characteristic is realized by using the orthogonal mixed feeding containing aperture coupled and proximity coupling feeding,two bands are matched by loading the reactance;the unidirectional radiation is achieved to improve the unit antenna gain by adding a reflector.The isolation is better than-23 dB,and the dual-frequency dual-polarization characteristics is good.Its structure is simple and easy to produce.The measurement results have a good agreement with the simulation results,demonstrating the feasibility that the wide-slot structure can be applied to achieve dual-frequency characteristic.2.On the basis of studying wide-slot microstrip antenna,a new type of dual-band dual-polarized wide-slot planar antenna is proposed.It uses a double-layer stripline structure with a common ground,having a wide slot etched on each ground,and the two proximity coupling feedlines are orthogonally located at different layer.The working bandwidths are improved by cutting the corners of square slot,introducing foam layers and loading triangle stub at the terminal of feedline,with a metal cavity paralleling to the whole structure for increasing its gain.And the dual-frequency characteristic is realized by controlling the coupling degree.Then,the influence of each parameter on the antenna performance is analyzed.And the two working bandwidth can reach 15% and 17.9%,respectively,and the port isolation is better than-19 dB.After comparing the performances with the firstly designed antenna,the latter is selected for the design of Ku-band dual-band dual-polarized high-gain array antennas.3.In order to obtain higher gain,this paper further designs a four-element dual-band dual-polarized high-gain planar array antenna based on double-layer wide slot stripline antenna.After the research of the basic feeding network theory and the reverse-phase feeding technology,a inverting feed network is designed to optimize the cross-polarization characteristic of the array,and the influence of the element spacing on the array performance is analyzed.The analysis result shows that the gain of 13.8 dB and 13.7 dB is obtained at the center frequency of the two bands when guaranteeing the expected working bandwidth,indicating the good radiation characteristic.And the measurement results and the simulation results are in a good agreement.This four-element array can be extended to become a larger planar array antenna to meet the actual engineering requirements to receive the Ku-band signals for the broadcasting video satellite.