An Omnidirectional Dual Circularly Polarized Antenna Feed from the Same Side

Abstract

The invention provides an omnidirectional dual circularly polarized antenna with same-side feeding. The antenna comprises a radiation structure, a similar coaxial impedance matching structure, and a radio frequency excitation conversion T-shaped connecting structure, the similar coaxial impedance matching structure is divided into an upper similar coaxial impedance matching structure and a lower similar coaxial impedance matching structure, the upper end and the lower end of the radiation structure are respectively connected with the lower end of the upper similar coaxial impedance matching structure and the upper end of the lower similar coaxial impedance matching structure, the upper end of the upper similar coaxial impedance matching structure is sealed by a metal disc plate, the lower end of the lower similar coaxial impedance matching structure is connected with the radio frequency excitation conversion T-shaped connecting structure, and an interface of the radio frequency excitation conversion T-shaped connecting structure can directly perform radio frequency excitation by employing an SMA joint feed line. According to the antenna, the omnidirectional performance and the axial ratio performance are good, a certain working bandwidth of -10dB bandwidth 600M (5.2GHz-5.8GHz) is achieved, and in-band gain is greater than 5.2dB and can reach 6.7dB to the maximum.

Description

technical field [0001] The present invention relates to an antenna, in particular to an antenna capable of realizing omnidirectional dual circular polarization by feeding on the same side. Background technique [0002] Circularly polarized antennas are more and more widely used because of their ability to receive and transmit incoming waves with arbitrary polarization. In many application scenarios, received and transmitted signals come from all directions. In order to better handle these signals, omnidirectional circular polarization performance must be achieved. However, the gain reduction due to omnidirectional is more obvious. [0003] After literature search, the article "Wideband Omnidirectional Circularly Polarized Patch AntennaBased on Vortex Slots and Shorting Vias" published in IEEE Trans.Antennas Propag. in 2014 by Dan Yu, Shu-Xi Gong et al. proposed an omnidirectional circularly polarized For the antenna, although the 10dB impedance bandwidth reaches 51.7%, and...

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Problems solved by technology

However, the gain reduction caused by omnidirectional is more obvious

[0003] After literature search, the article "Wideband Omnidirectional Circularly Polarized Patch AntennaBased on Vortex Slots and Shorting Vias" published in IEEE Trans.Antennas Propag. in 2014 by Dan Yu, Shu-Xi Gong et al. proposed an omnidirectional circularly polarized Antenna, although the 10dB impedance bandwidth reaches 51.7%, and the 3dB axial ratio bandwidth also reaches 57.8%, but the in-band gain is less than 2dBic

[0004] In addition, even if high omnidirectional gain and dual circular polarization characteristics can be achieved, it is still a problem whether the dual circular polarizations can not interfere with each other

After literature search, the article "Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder" published by Zhou Bin, Junping Geng and others in the International Journal of Antennas and Propagation in 2015 proposed an omnidirectional dual circularly polarized antenna, although In the frequency band, the gain of about 5dBic and good circular polarization characteristics are realized. However, since the left and right circular polarization feed ports are distributed at both ends of the antenna, if the antenna wants to achieve horizontal omnidirectional circular polarization, the antenna must be placed vertically. At present, it is more convenient to use a cable to connect the lower feeder port, but the drooping part of the cable connected to the upper feeder port will definitely affect the radiation pattern, thus destroying the circular polarization characteristics of the loop antenna, resulting in the antenna needing to implement different circular poles. It needs to be reinstalled when upgrading, which brings inconvenience to users

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