A low-profile transmitarray operating at E-band (72–86 GHz) is discussed. The antenna thickness including the power divider and the radome is 58 mm. Furthermore, the flat-lens aperture is equal to 133.7 mm × 133.7 mm and the focal-to-aperture size ratio F/D is less than 0.3. The low profile has been obtained by using a specific quad-feed source. The antenna has been fabricated and characterized. In good agreement with the numerical simulations, a peak gain of 37.0 dBi and a 3-dB gain relative bandwidth larger than 17.7% have been achieved, respectively. The aperture efficiency is larger than 33%.