A Compact Fractal-Shaped O-Ring Monopole Antenna for Modern Broadband Wireless Applications

In this letter, the design of a compact planar Fractal-shaped O-ring monopole antenna based on the Sierpinski carpet concept is studied and proposed for modern broadband wireless applications. The planar fractal-shaped O-ring monopole antenna is on the basis of Sierpinski category construction and then modifies the state of the plane inward with a radius of 27mm over the two iterations. The antenna structure is low profile and easy to be fabricated, and it has performed the simulation and measurement with the result VSWR ≤ 2 that can achieve a wide impedance bandwidth 636% from the frequency band 1.57GHz ~ 10GHz. The geometric scale factor of the Sierpinski fractal is according to the same scale element that defines the geometrical self-similarity. In our experiments, the results show that use of fractal-shaped O-ring into monopole antenna structure can effectively improve input impedance matching, and obtain a larger bandwidth and better radiation pattern, while also having predictable multi-band characteristics.