A Dual-Broadband Circularly Polarized Shared-Aperture Array Antenna for C-/K-Band Application

This paper presents a dual broadband circularly polarized (CP) array antenna with shared aperture for C- and K-band application. First, the CP operation for C-band element is generated by four square ring patches which are fed by an unequal cross slot. Second, a CP magnetoelectric (ME) dipole antenna with one pair of horizontal patches connected is used as the main radiator for K-band. The coupling slot etched on the ground is modified as cross-shaped to enhance the CP bandwidth. Last, a C-band 2×2 array and K-band 4×4 array are interlaced together at a shared aperture. The simulated results show the proposed antenna exhibits a -10-dB impedance bandwidth of 16.5% and 3-dB AR bandwidth of 16.2% at C-band, while has a -10-dB impedance bandwidth of 52.4% and 3-dB AR bandwidth of 33.7% at K-band.