Aperture Shared Multi-Band Circularly Antenna for Beidou Navigation Application

In this conference, an aperture-shared multi-band circularly polarized antenna is presented. It contains a cross dipole type antenna operating at the high-frequency band and microstrip type patch antenna operating at low-frequency bands. The low band (LB) microstrip type patch antenna is underneath the high band (HB) cross dipole type antenna. For this arrangement, the coupling interference of the HB to LB antenna is the dominant influence between HB and LB antenna. Because of the coupling interference, the VSWR of the LB antenna generates undesirable peaks with different lengths of the HB antenna feeding cables at LB. Thus, an HB antenna loading with a parasitic cross loop (PCL) is designed to decrease the coupling interference between LB and HB antenna. By attaching the proposed PCL to the HB antenna, the undesirable peak in VSWR of the LB antenna is suppressed. Furthermore, the proposed ASA is fabricated and measured.