3-D-printed phase-rectifying transparent superstrate for resonant-cavity antenna

A 3D printed non-planar highly transmitting superstrate is presented to improve the directive radiation characteristics of a resonant cavity antenna (RCA). Classical RCAs are reported with non-uniform aperture-field distribution that compromises their far-field directivity. The concept of nearfield phase correction has been used here to design a phaserectifying transparent superstrate (PRTS), which was fabricated using 3D printing technology. The PRTS is printed using easily accessible polylactic acid (PLA) filament. It has a significantly lower cost and weight compared to its recently published counterparts, while its performance is comparable. The 3D printing technology yielded the prototype in less than four hours, which is considerably less compared to traditional machining methods. Measurements of the prototype indicated close correspondence between the predicted and the measured results. Significant increase in antenna performance has been achieved, due to rectification of aperture phase distribution. Notable aspects encompass 7.3 dB increase in the antenna peak directivity (from 13 dBi to 20.3 dBi), significant side-lobe level suppression, and an improvement of aperture efficiency by 36.1%, with a PRTS that costs less than 2.5 USD.