Ultra wide band miniature fractal antenna

Abstract

The invention discloses an ultra wide band miniature fractal antenna which mainly comprises a ground plate, a twin-whip antenna and an impedance conversion transmission wire, wherein the twin-whip antenna comprises two metal columns vertically arranged on the ground plate; the impedance conversion transmission wire is arranged on the upper surface of the ground plate and is embedded between two metal columns of the twin-whip antenna; the impedance conversion transmission wire comprises at least two metal strips with different widths, the metal strips are arranged according to the order of from small width to big width and connected in an iteration manner in the length direction of the metal strips, wherein the metal strip with minimum width is connected with one metal column of the twin-whip antenna and the metal strip with maximum width is connected with the other metal column of the twin-whip antenna. The ultra wide band miniature fractal antenna can keep wider frequency band, higher radiation efficiency and better directional diagram characteristics while the size of the antenna is effectively reduced.

Description

technical field [0001] The invention relates to an antenna device, in particular to an ultra-wideband miniaturized fractal antenna. Background technique [0002] At present, quarter-wavelength monopoles, electrically small antennas, or conventional Hilbert fractal structures are often used to complete the design of short-wave or ultra-short-wave antennas. However, the above-mentioned design schemes have certain deficiencies: if a quarter-wavelength monopole is used to design a short-wave or ultra-short-wave antenna, since the length of the antenna is inversely proportional to the operating frequency, when the designed antenna needs to have a lower operating frequency , the length of the antenna is longer, so the mobility, erectability and concealment of the antenna are relatively poor. Using an electrically small antenna to design a short-wave or ultra-short-wave antenna will greatly increase the Q value of the antenna, reduce the radiation efficiency of the antenna, and li...

AI Technical Summary

Problems solved by technology

However, the above-mentioned design schemes have certain deficiencies: if a quarter-wavelength monopole is used to design a short-wave or ultra-short-wave antenna, since the length of the antenna is inversely proportional to the operating frequency, when the designed antenna needs to have a lower operating frequency , the length of the antenna is longer, so the mobility, erectability and concealment of the antenna are relatively poor

Using the conventional Hilbert fractal structure to design short-wave or ultra-short-wave antennas can reduce the size of the antenna, but in order to ensure the mobility and erectability of the antenna, usually only the first-order Hilbert curve is used

For the conventional Hilbert fractal structure, when the size of the antenna is reduced to k 0 a0 is the wave number, and a is the minimum radius surrounding the antenna), the radiation efficiency of the antenna decreases rapidly, the working bandwidth of the antenna is limited, and the input impedance of the antenna feed point changes drastically with frequency, which is very unfavorable for the design of the matching circuit

In addition, the meander effect caused by fractals may cause the antenna to have more serious cross-polarization characteristics, which will further seriously affect the pattern characteristics

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