Focused transmitarray antenna using I-shaped slot elements for microwave measurements

A focused transmitarray antenna is presented in this Letter. To appraise the antenna, a quad-metallic-layer focused transmitarray antenna using I-shaped all-metal slot elements with an air gap between every two layers has been analysed, simulated and measured. It is illustrated that the electric field strength value at a distance of 3.1λ0 from the transmitarray antenna reaches a maximum at 9.3 GHz operating frequency. It is the first time that a focal plane of approximately one wavelength has been achieved with a focused transmitarray antenna consisting of all-metal elements. Simulated and measured results show that the proposed antenna has good concordance, making it possible for microwave measurements.