Linear Phased Array Antenna Fed by the Modified Dielectric Image Line

A linear phased array antenna fed by the modified dielectric image line (DIL) is proposed in this letter. The array contains 16 subarrays, and one subarray consists of eight patch antenna elements fed by one modified DIL through eight coupling apertures on the ground plane. The modified DIL can enhance the electromagnetic field confinement in the DIL, which is beneficial to reduce the mutual coupling between parallel DILs. According to the measured results, the coupling between two modified DILs has been reduced by about 5 dB compared with that in the original DILs when the length is 160.5 mm. Finally, the proposed array achieves a wide fractional bandwidth of over 20% with voltage standing-wave ratio (VSWR) less than 2.5 when scanning up to ±60° in the H-plane in 8∼10 GHz. The isolation between the two adjacent ports is higher than 20 dB. A 16 × 8 array prototype is measured to verify the validity of the design.