Design Of Ultra-Broadband Dual-Polarization Probe For Near Field Measurement

With the continuous upgrading of communication equipment,the antenna is developing towards the direction of high performance and high practical value,and the test of the antenna performance relies on the antenna measurement system.Among,the near-field antenna measurement is very popular in the area of antenna measurement,and the probe is a vital part of the near-field measurement system.Its quality directly affects the efficiency of the test and the accuracy of the test results,so its performance requirements are very strict.Aiming at the drawbacks of traditional probes with narrow bandwidth and low test efficiency,a series of high-performance ultra-wideband dual-polarization probes are designed in this paper.The specific contents are as follows:1.Design of ultra-wideband dual-polarization conventional Vivaldi probe.A single-polarized Vivaldi antenna was designed by loading parasitic patches on the top and curved slots on the radiating arms,and then a dual-polarized probe was obtained by translating the feed network and placing it orthogonally.According to the simulation results,the probe can work at 0.4-6GHz,the overall size is110mm×170mm×0.7mm.In the working frequency band,the VSWR is less than 2,the port isolation is greater than 28dB,the cross-polarization isolation is greater than 22dB,and the radiation pattern of the probe has good symmetry.2.Design of ultra-wideband dual-polarization antipodal Vivaldi probe.By improving the single-slot AVA structure into a double-slot AVA structure loaded with an inverse structure,and the single-polarization double-slot AVA is designed by loading unequal-length rectangular slots on the double-slot AVA structure.Then,a dual-polarization probe is obtained by extending the substrate and placing the L-shaped vertically.From the simulation results,the probe can work at 0.4-6GHz,the overall size is100mm×180mm×0.9mm.In the working frequency band,the VSWR is less than 2,the port isolation is greater than 27dB,the cross-polarization isolation is greater than 29dB.The probe is processed and tested,the test results show that the VSWR is lower than 2,the port isolation is greater than 25dB,and the cross-polarization isolation is greater than 27dB.3.Design of ultra-wideband dual-polarization dual feed point Vivaldi probe.The single-polarized dual feed point Vivaldi antenna is designed by loading the matching structure at the input,loading the short-circuit matching branch at the top,and loading the arc-shaped metal parasitic strip on the substrate.Then,a dual-polarization probe is also obtained by panning the feed and placing it vertically.The probe can work at 0.4-6GHz,the overall size is 80mm×180mm×1.4mm.The probe is processed and tested,there is no significant difference between the simulation and test results.From the test results,it can be seen that the VSWR is less than 2,the cross-polarization isolation is greater than 27dB,the port isolation is greater than 35dB,and the radiation pattern of the probe has good symmetry.4.Two ultra-wideband dual-polarization probes are designed for high-frequency antenna measurement simulation.Based on the ultra-wideband dual-polarized dual feed point Vivaldi probe structure,the overall structure of the probe is simplified according to the matching characteristics,and two probes suitable for high-frequency antenna measurement are designed.The working frequency bands of the two high-frequency probes are 4-18GHz and10-40GHz,and the sizes of the probe are 29mm_×62mm×1mm and12mm×25mm×0.4mm,respectively.In the respective working frequency bands of the two probes,the port isolation is greater than 28dB,the VSWR is less than 2,and the cross-polarization isolation is greater than 28dB and 30dB,respectively.