Research On Tri-polarization Post-wall Slot Antenna

MIMO isan effective technique to improve the spectrum efficiency, and polarized MIMO is one of MIMOtechnology.Because of the characteristics of space utilization,polarized MIMO has been successfully used in microwave and satellite communications. Tri-polarization antenna is a key component of the tri-polarization MIMO system, especially thoseco-locatedtri-polarization antenna can obtain three times the system capacity as single polarization system, else it occupy small space. But miniaturization, isolation and cross-polarization of the co-located tri-polarization antenna is difficult, especially when there are volume restrictions requested. This paper research on tri-polarizationPOST-WALL slot antenna.(1)This paper purposes a POST-WALL slot line, whose both sides have periodicity metal vias. The metal vias can reduce the characteristic impedance of the line and the phase velocity of main mode, which lay the foundation for miniaturization of antenna.(2) This paper proposes dual-band tri-polarizationPOST-WALL slot antenna. This antenna combination of slot lines with metal vias and ordinary slot line, which formed step impedance slot antenna,and add periodicalstub on conductor surface.This not only realizesthe miniaturization of the antenna, but also makes antenna dual-band. This paper makes a dual-band tri-polarizationPOST-WALL slot antenna, frame length and width is 35 mm and 30 mm, respectively, center slot length and width is 30 mm and 2mm, respectively. Simulation and experimentalresult show that this antenna operatingfrequencies are 2.43 GHz and 4GHz.Bandwidth are 114 MHz and 439 MHz,respectively. All sport isolation between antenna elementsis greater than 22 dB and 27 d B, respectively, which shows mutual coupling is little. Beside, in E-plane the difference between the co-polarization and cross-polarization is greater than 12 dBat 2.43 GHz and 17 d B at 4GHz. This antenna can be applied to volume-demanding condition.(3) This paper purposes tri-polarizationco-located slot antenna, whose structure is symmetry. Simulation and analysis of the impact of the slit stub size and vias location and other parameters on antenna performance are conducted, and then chose an optimized size. The simulation and experimental results are consistent.This tri-polarizationantennaoperating at 2.47 GHz, bandwidth is form 2.432 GHz to 2.505 GHz. The three-port isolation between antenna elementsis greater than 25.1dB. In E-plane, the difference between the co-polarization and cross-polarization is greater than 13 dB, moreover, the maxed difference between the co-polarization and cross-polarization of single antenna element is 16.5dB. This antennais suitable for condition of high polarization purity and isolation, especially for polarization diversity applications on abundant scattering environments.Research of abovementionedantennas extends the applicability of multi-polarization MIMO system.