Dual-Band Minkowski Fractal Patch Antenna With Polarization Diversity

A novel dual-band microstrip-line-fed Minkowski fractal patch antenna, exhibiting two different polarization characteristics over the operating bands, is presented. The design of the structure is systematically developed from the Theory of Characteristic Modes (TCM). The antenna operates at frequencies 1.5 GHz and 2.45 GHz respectively, which establishes its use for the GPS and ISM band applications. For the first band of operation a circularly polarized behavior is observed, with an axial ratio bandwidth of 19MHz (AR ≤ 3dB), whereas for the other the structure behaves as a linearly polarized radiator. The antenna geometry is examined using the concept of characteristic modes and then the simulations are carried out to validate the performance of the structure.