A Novel PRAMC-Based Ultralow-Profile Transmitarray Antenna by Using Ray Tracing Principle

In this paper, a novel ultralow-profile transmitarray (TA) is proposed by using multifolded ray tracing principle. The proposed TA unit cell would reflect the incident wave of x-polarization as a ground and transmit the incident wave of y-polarization with arbitrary phase shift in the operating frequency band. A broadband polarization rotation reflection surface based on artificial magnetic conductor with small phase difference in wide range of incidence angle is applied to transform the polarization of incident wave. Two kinds of TA antennas at 28 GHz are studied, where the distances between the source and the TA are, respectively, reduced to 1/3 and 1/4 of the focal length (named as TA antennas I and II), which are much less than that of the conventional TA antennas. The simulated results show that the proposed TA antennas can achieve -1 dB gain drop bandwidth of 5% and cross-polarization level of less than -30 dB, and the maximum aperture efficiencies can achieve 46% and 40%, respectively. For demonstration, the TA antenna I is fabricated and measured. Good agreement can be observed between the measurement and simulation.