Dual-Band Co-Aperture Planar Array Antenna Constituted of Segmented Patches

A novel dual-band co-aperture planar array antenna is proposed in this letter. The radiating elements operating at a higher frequency band are grouped and reused for the lower frequency band by adopting the concept of segmented patches. A total of 4 × 4 “H”-shaped patches, fed by two independent microstrip-feeding networks through rectangular slots, are taken as the radiating elements for a 4 × 4 higher-band array antenna, and simultaneously as the radiating elements for a 2 × 2 lower-band array antenna. Although the frequency ratio of the higher band to the lower band is over 2, grating lobes are avoided. A validation model is fabricated, and measured results demonstrate a working bandwidth of 8.8% from 5.4 to 5.9 GHz and another working bandwidth of 7.3% from 13.2 to 14.2 GHz. The reflection coefficients are less than -10 dB and the radiation efficiencies are higher than 65% throughout both frequency bands.