Dual-band dual-polarized antenna for medical applications

The design of a coplanar waveguide fed antenna with dual polarization and dual-band operation is presented. The antenna operates in the Industrial, Scientific and Medical (ISM) bands. The design presented has linear polarization in the lower ISM band (2.45 GHz) and circular polarization (CP) in the higher ISM band (5.8 GHz). It is demonstrated that a fractional bandwidth for CP larger than 33% can be attained simply by introducing an inverted L-shaped slot in the ground plane and aligning another inverted L-shaped strip in a parallel position to it. The advantages of the proposed antenna are the simple yet efficient design of the radiator, dual polarization, a wide 3-dB axial ratio operating band, and a very compact size.