| The popularity rate of radio communications is increasing dramatically, since the high speed progress of technology and economy. Consequently, radio monitoring equipment needs to expend from the original VHF frequency band to UHF or microwave frequency band. The broadband communications system leads to more requirements for antenna. The requirements for antenna for radio monitoring of are: boarded bandwidth frequency, minimized volume, multiplied polarization and good Omni-directional radiation characteristics. In order to meet the above requirements, this study researched the antenna of the monitoring car in Gansu province. A wireless communication frequency band for monitoring the electromagnetic miniaturized broadband Omni-directional vehicle antenna was designed and optimized. The designed used combination of operating bandwidth structural variations and tie shaped planar miniaturization technology which effectively boarded the antenna bandwidth. The antenna was tested by using high-frequency electronic simulation software to get the antenna VSWR civilian communications band and far-field radiation characteristics.then the test results showed that the antenna has good impedance characteristics and broadband vertically polarized Omni-directional radiation characteristics. Secondly, a horizontally polarized Omni-directional minimized broadband antenna for vehicle was designed. The design used horizontal dipole structure combined frequency independent broadband transducer array. The special combination was formed by the power of the antenna configuration and passed simulation and tests. The antenna impedance bandwidth is relatively wide to achieved the level of realized the full-band VHF broadband radiation. The designs in this study met the antenna volume requirements for vehicle to integrate the system easily. Meanwhile, the electromagnetic character of antenna is sufficient for endless radio antenna monitoring. |
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