Phased Array Antenna With Top-Truncated Dome Lens for Wide-Angle Scanning

A phased array antenna (PAA) incorporating a dielectric dome lens (DL) extends its scanning range but concurrently experiences a notable reduction in broadside gain due to the inherent diverging lens characteristics near the broadside. Instead of using a whole dielectric DL, this article proposes a dielectric top-truncated dome lens (TTDL) to address this issue. The approach mitigates broadside gain reduction by eliminating the dielectric DL's inherent diverging characteristics near the broadside through truncation of its upper portion. The study elucidates the design fundamentals for the dielectric TTDL, encompassing an analysis of the truncation impact and the corresponding phase compensation strategy aimed at mitigating this truncation effect. Utilizing ray-tracing methods and full-wave simulations, this work comprehensively evaluates the performance disparity between the TTDL and conventional DL, revealing the effectiveness of the proposed approach. Additionally, the structural flexibility of the TTDL is discussed to facilitate a more compact architecture. Experimental validation of a TTDL antenna, incorporating a feed array and a compact dielectric TTDL, is presented. Results demonstrate that within the 26.5 to 29.5 GHz operating band, the compact TTDL effectively extends the scanning range from 60 degrees to 80 degrees while avoiding broadside gain reduction and maintaining a gain fluctuation within 5 dB.