Millimeter-Wave Wideband Wide-Angle Scanning Linear Phased Array Antenna Using Pin-Loaded Slot Elements

A novel wideband, wide-angle scanning linear phased array with low gain fluctuation is introduced for millimeter-wave (mmW) applications. The design utilizes a full-metal long slot as its radiation structure to simultaneously achieve wideband and low-loss performance. To ensure low gain fluctuation across a wideband, wide-angle scanning range, an innovative structure incorporating two pins and grooves is implemented outside the ridges. This design facilitates a promising gain enhancement mechanism for wide-angle scanning, which is explored through the analysis of the field distribution of the element with periodic boundaries. The ridge gap waveguide (RGW) technology is employed to feed the elements, offering a wide single-mode bandwidth, reduced loss, and compact physical width. To validate the design, a $1\times 16$ array prototype with two distinct feeding networks was constructed to achieve radiation both at the broadside and 60°. The measured VSWR for both radiation states remains under two across almost the entire band, confirming the array’s wideband, wide-angle scanning capabilities. The measured and simulated radiation results show a good agreement from 20 to 30 GHz, showcasing a peak gain of 19.2 dBi and maintaining a gain fluctuation under 2.5 dB within a ±60° scanning range.