Circularly Polarized Dielectric Resonator Antenna Fed by Off-Centered Microstrip Line for 2.4-GHz ISM Band Applications

A special feeding technique of an off-centered microstrip feedline slot-coupled circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) for 2.4-GHz industry, science and medicine (ISM) band applications is reported in this letter. Good CP characteristics can be achieved using two coupling points with a quarter-wavelength path difference and 90^° phase shift, resulting in a series feeding circuitry. The 10-dB impedance bandwidth and the 3-dB axial ratio of the proposed antenna are 141 and 85 MHz, respectively. Details of the antenna design procedure are described and typical experimental results are presented and discussed.