A Dual Frequency Circularly Polarized Planar Antenna

Abstract

The invention discloses a dual-frequency circularly polarized planar antenna. On a dielectric substrate, the anti-symmetrical arrangement of the top-layer anti-symmetrical U-shaped radiation unit and the bottom-layer anti-symmetrical U-shaped radiation unit are respectively designed to connect the top-layer anti-symmetrical U-shaped radiation unit. The unit and the bottom antipodal U-shaped radiation unit form a closed symmetrical square ring. Then a non-closed resonant cavity is introduced to radiate on the non-closed side. The resonant cavity connects the antipodal U-shaped radiating unit on the top layer and the U-shaped radiating unit on the bottom layer, and the axes of the closed symmetrical square ring are parallel to each other. The phase-shift line whose length is three-eighths of the wavelength is connected to realize a 90° time phase difference, so that the antenna has dual-frequency circularly polarized radiation characteristics. The dual-frequency circularly polarized planar antenna realized by the present invention can effectively affect the 3dB axial ratio bandwidth by the structural arrangement of its phase-shift line, and the dual-frequency characteristics of the antenna are determined by different working modes of the square-ring radiation unit.

Description

technical field [0001] The invention relates to a dual-frequency circularly polarized planar antenna, which belongs to the field of microwave technology. Background technique [0002] Since the 1990s, dual-frequency antennas have been deeply researched and developed rapidly. Especially since the mobile communication boomed at the end of the last century, the existing frequency bands have become increasingly crowded. In order to increase the number of channels, new antennas are often required. frequency band, and considering compatibility, it is often required to use a set of equipment to work in dual-band or multi-band. The strong demand continues to promote the design and development of dual-band / multi-band antennas. For example, the Global System for Mobile Communications (GSM) has GSM900 GPS and GSM1800 are two commonly used working frequency bands, and satellite positioning systems such as GPS usually use multiple frequencies to work. Similarly, the wide application of ...

AI Technical Summary

Problems solved by technology

The design idea of ​​a common dual-frequency circularly polarized antenna is generally to combine two circularly polarized resonant units of different frequencies into a dual-frequency circularly polarized antenna by means of resonant overlapping technology. For example, in the design of traditional microstrip patch antennas, usually A layer of resonant patch will be added to form a double-layer patch microstrip antenna on the patch of another frequency, or the combination of microstrip patch and slot is also a common implementation form of dual-frequency circularly polarized microstrip antenna, but The above implementation methods are difficult to manufacture and are not conducive to integration

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