3-D-Printed Comb Mushroom-Like Dielectric Lens for Stable Gain Enhancement of Printed Log-Periodic Dipole Array

A three-dimensional (3-D)-printed comb mushroomlike dielectric lens (DL) for stable gain enhancement of the antipodal printed log-periodic dipole array (PLPDA) antenna is presented. The low-profile DL is specially designed to be easily integrated with the antenna source for improving its gain performance. Periodic comblike structure is also utilized in the DL to obtain the desired effective permittivity according to the effective medium theory. Both the design process and lens fabrication greatly benefit from 3-D printing technology. With this novel manufacturing method, the lens structure can be designed with greater design freedom and flexibility, which is hard to realize by the conventional manufacture process. Loaded with the proposed 3-D-printed comb mushroomlike DL, the PLPDA antenna has 11.2 ± 0.7 dBi flat gains in the operating frequency band (14-20 GHz), which means a 4.7 dB prominent gain increment and a very flat gain feature in the wideband.