Experimental investigation of ka-band pyramidal horn antenna array for Millimeter Wave Active Imaging System

Ka-band compact pyramidal horn antenna (PHA) array is an important research topics to improve the image quality of millimeter wave active imaging system. In this paper, PHA array with WR28 metal waveguide direct feeding is specially designed based on theory analysis and computer simulation. It includes the design of PHA unit, feed-in source, PHA array and so on. Finally, the parameters are measured as following: bandwidth is 26.5GHz ~ 40GHz, voltage standing-wave ratio (VSWR) is less than 1.30, gain is from 12dB to 16dB, mutual coupling of sending and receiving units is less than -40dB, which are close to the results of theory analysis and simulation. The image quality of Millimeter Wave Active Imaging System with PHA array is much better than that with dielectric rod antenna array.