Low Profile Magnetoelectric Dipole Antenna Design

The wireless communication system is changing with each passing day,and in order to meet various communication requirements,higher requirements are put forward for antenna performance.It is hoped that it has the attributes of low profile,wide band,low cross-polarization,low back radiation,stable gain,simple structure and low cost.Due to its own structural characteristics,the magneto-electric dipole antenna shows superior performance.On the basis of the work of many scholars,this paper carries out the research on low-profile magneto-electric dipole antenna.The main contents are as follows:(1)Design of broadband low profile magnetic electric dipole antenna.On the basis of studying the design method of typical low-profile magneto-electric dipole antenna,two ideas of Broad-band are proposed.One is to improve the electric dipole,and the other is to improve the way the magnetic dipole folds.Based on the above ideas,three kinds of antennas were designed.The impedance bandwidth was expanded by E-slotted on the wide side of the electric dipole and the antenna height was not changed.Although the low-frequency gain was basically unaffected,the high-frequency gain was significantly improved.By loading a short-path bridge on both sides of the electric dipole,the impedance bandwidth is effectively expanded and more stable without changing the antenna height.In addition,compared with the antenna without short-path bridge,the antenna gain in the whole working band is improved to varying degrees,especially in the high frequency part,and the maximum gain can reach 13.35 d B.By improving the magnetic dipole folding mode,the impedance bandwidth of the antenna is 87.97%,and the gain in the working frequency band is stable around 9 d B,but the gain in the high frequency part decreases to the lowest point of 6.87 d B and then increases gradually.The three antennas all maintain the characteristics of low cross-polarization,good directional radiation and basic symmetry of plane E and H pattern of the magneto electric dipole antenna.(2)Design of circularly polarized low-profile magneto-electric dipole antenna.Based on the research of circularly polarized antenna,circularly polarized antenna is realized by changing the form of electric dipole.One is a low-frequency antenna,using folded feed,Circular polarization is realized by using rotationally symmetric electric dipole and loading angular back cavity,which makes the antenna obtain60.8% relative bandwidth and 49.4% axial ratio bandwidth,and the gain changes in the range of 4.37-7.68 d B.The other is a high-frequency antenna,which generally has the problem of narrow impedance bandwidth and axis ratio bandwidth.In this paper,the upper metal patch is perturbed and corner-cut by SIW slot coupling feeding and using the method of microstrip antenna to realize circular polarization for reference.The impedance bandwidth is 34.5%,the gain is stable at about 6 d B,and the axial ratio bandwidth is 12.7%.Finally,the processing test of the designed antenna shows that the test results are consistent with the simulation results,which further verifies the feasibility of the magnetic dipole antenna broadband and circular polarization design ideas.