An Ultra-wideband Fractal Antenna with Circular Rings Based on Coplanar Waveguide

As the rapid development of wireless communication technology, the antenna has become a key part in communication systems. In various antennas, the fractal antenna was ever thought of as very promising. A fractal structure refers to a geometric body with self-similarity in structure. Its mathematical foundation is fractal geometry. At present, there are few studies on sub-type antennas, and the current research status of sub-type broadband antennas is that the fractal structure is limited and more complicated. An ultra-wideband fractal antenna is proposed in the paper. The antenna is composed of four rings with different radii and 8 short-circuit stubs with an angle difference of 45°. Through the nesting of the rings, the current path is changed, and the miniaturization is realized. The antenna is feed by a coplanar waveguide (CPW) and the ultra-wideband feature can be achieved. The frequency band of the final antenna with S
11
< -10 dB is 4.03–13.42 GHz, and the antenna has good radiation characteristics and gain.