Millimetre-wave end-fired antenna array for active 3D holographic imaging system

A compact Ka-band (26.5–40 GHz) dielectric rod end-fired antenna array for the three-dimensional (3D) active holographic imaging system is presented. Without horn shape feeding, the new antenna array is specially designed with characteristics such as small size, high gain, good radiation pattern, easy realisation, low insertion loss and low mutual coupling. In the imaging system, the spacing of sending and receiving antenna units is 1.5 wavelengths with mutual coupling <−30 dB and a gain of 12–16 dB. The results and analysis provide guidelines for the design of millimetre-wave end-fired antenna arrays.