A Planar Millimeter-Wave Diffuse-Reflection Suppression 4-D Imaging Radar Using L-Shaped Switchable Linearly Phased Array

This article proposes a scatter suppression L-shaped phased-array imaging radar. The system operates at 24–26.4 GHz and is capable of 4-D imaging to determine the distance, elevation, azimuth, and speed of targets. It utilizes a frequency-modulated continuous-wave (FMCW) signal with a bandwidth of 2.4 GHz to extract range information, resulting in a range resolution of 62.5 mm. Orthogonal L-shaped linearly phased arrays are used for both transmission and reception. The azimuth and elevation angle information are obtained by switching the radiation beams of the phased arrays. The radar exhibits good scanning capabilities in 2-D space, with a scanning field of view (FOV) over 100° and an angular resolution of 3°. Importantly, the imaging artifacts due to multiple diffuse reflections can be suppressed by switching the transmit and receive phased-array antennas. A prototype is manufactured using the printed circuit board technology, which has a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$23.5\times 23.5$ </tex-math></inline-formula> cm2. Experimental validation of the design has been conducted. The proposed radar architecture and array layout reduce the complexity of the baseband, offering advantages such as easy implementation, high integration, and low cost, showing promising prospects for potential sensing applications.