LAUSR

A new structure for transmitarray antennas is presented. The proposed semiplanar transmitarray keeps certain geometrical curvature, that the required transmission phase range is reduced significantly from 360°, causing an increase in bandwidth and efficiency. The proposed antenna structure has varied element thickness—the central element being the thinnest and elements growing in thickness as we move toward the edges. To evaluate the new model, an X-band prototype antenna is fabricated with the number of layers for the elements growing from 2 to 5 from center to the edges of the aperture. The required phase range for the elements was reduced from 360° to 51.5°. Measurement results show that proposed antenna with aperture size of ${\text{21.8}}\lambda _{0}^{2}$ has 22.3 dBi maximum gain at 10.3 GHz. In addition, the proposed design achieves a 24.27% 1 dB gain bandwidth and 62% efficiency.