Circularly Polarized Crossed Dipole With Magnetoelectric Dipole for Wideband and Broadbeam Applications

A single-feed circularly polarized (CP) crossed dipole loaded with a magnetoelectric (ME) dipole is presented to enhance the bandwidth and beamwidth in this paper. The double-sided orthogonal strip-shaped dipoles are fed by a pair of vacant-quarter printed rings to realize CP radiation. A ME dipole is introduced to generate another resonance so that the CP bandwidth is significantly broadened. The antenna is backed with a corrugated cavity to obtain unidirectional radiation with high front-to-back ratio and a wide 3-dB axial ratio (AR) beamwidth. Simulated results show that the proposed antenna with an overall size of 0.584 lambda(0 )x 0.58 lambda(0) x 0.15 lambda(0) at 1.45GHz exhibits an impedance bandwidth of 72.1% for vertical bar S-11 vertical bar <= -10dB from 1.25-2.66GHz, a 3-dB AR bandwidth of 45.3% from 1.45-2.3GHz, an average boresight gain of 8.1dBic and a high radiation efficiency over 94% within passband. Moreover, the 3-dB AR beamwidth is greater than 162 degrees from 1.85-2.25GHz.