Small circularly-polarized antenna

Abstract

The invention relates to a small circularly-polarized antenna comprising a feeding plate and four radiation oscillators mounted on one side face of the feeding plate. The feeding plate is provided with a feeding network, and the feeding network has four output ends which are respectively connected with the four radiation oscillators and used for generating four equal-power signals, of which the phase difference is 90 degrees, and respectively outputting the four signals to the four radiation oscillators. The radiation oscillators are PIFA oscillators, and low-loss insulating medium or gas of which the dielectric constant is greater than 2 is filled between horizontal portions of the radiation oscillators and the surface of the feeding plate. According to the small circularly-polarized antenna provided by the embodiment of the invention, by filling high-dielectric-constant low-loss insulating medium between the PIFA radiation oscillators and the feeding plate, the size of the antenna is greatly reduced, circular polarization is realized, and meanwhile, the cost of production is lowered. Compared with the prior art, the small circularly-polarized antenna of the invention has the advantages of small size, low profile, good circular polarization performance, high gain and the like.

Description

technical field [0001] The invention relates to the field of RFID application technology, in particular to a small circularly polarized antenna. Background technique [0002] Radio frequency identification is a non-contact automatic identification technology. In the RFID (Radio Frequency Identification, radio frequency identification) system, identification information is stored in an electronic data carrier, and the electronic data carrier becomes a transponder. The identification information stored in the transponder is read by the reader. In some applications, the reader can not only read the stored information, but also write data to the transponder. This read and write operation is through wireless communication between the two parties. to achieve. Microstrip antenna, as a commonly used directional antenna form in RFID system, is of great significance to the development and application of RFID. [0003] The structure of the early development of the microstrip antenna...

AI Technical Summary

Problems solved by technology

[0004] However, there are many deficiencies in the methods currently used, which will affect other performance indicators of the antenna.

For example, the use of short-circuit probe loading, while reducing the size of the antenna, will also bring some disadvantages: on the one hand, the impedance matching depends on the position of the short-circuit probe and the distance from its feeding point, which imposes strict requirements on manufacturing tolerances ; On the other hand, it is the problem of bandwidth reduction. If a reactive element is used to load, the bandwidth will also be reduced. If a resistive element is used, although it helps to expand the frequency band, the energy consumption of the resistive element will reduce the efficiency of the antenna.

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