Design of high efficiency broadband fresnel zone lens antenna at K band

In this paper, a novel 24 GHz flat Fresnel zone plate lens antenna has been presented. It consists of three dielectric layers separated by the air gaps and six identical metallic patterns printed on the top and bottom surfaces of each layer. According to the design principle of the quarter-wave Fresnel zone lens, three required phase correction schemes are chosen, -270 degree, -180 degree, and -90 degree, which are realized by tuning the width of the conducting shapes. Simulations show that the presented lens antenna has an aperture efficiency of more than 44.5% in the band of 21.7GHz~24 GHz, a directivity of 27.7 dBi, and a 1 dB bandwidth of about 10.18%.