A novel circular polarized antenna for minimally invasive devices

A novel planar dual-spiral monopole antenna with circular polarization (CP) operation is proposed. Dual asymmetrical strip-sleeves are utilized and shorted at the ground plane, the proposed CP design for 2.45 GHz band can easily be achieved and provides the impedance bandwidth (RL ≥10 dB) of about 240 MHz and the 3 dB axial-ratio (AR) bandwidth of about 130 MHz. The measured peak gain and radiation efficiency are about 9.1 dBic and 81 % across the operating bands, respectively.