Multibeam Hybrid Transmitarray Based on Polarization Rotating Metasurface With Reconfigurable Bidirectional Radiation

This article proposes a bidirectional multibeam hybrid transmitarray (HTA) using a transmission polarization-rotating metasurface (TPRM). A novel configuration is introduced to facilitate bidirectional beam-scanning by combining the transmitarray (TA) and folded-TA (FTA). To accomplish the reconfiguration of both unidirectional and bidirectional radiation states in the
$+z$
-,
$-z$
-, and
$+/-z$
-directions, a polarization switchable multifeed array (MFA) is placed at the focal plane between the TA and FTA, radiating x-polarization, y-polarization, and 45° oblique polarization waves, respectively. Meanwhile, the proposed antenna can achieve multibeam radiation in the three aforementioned states by switching the polarization of the MFA. To demonstrate the operating principle, a prototype has been designed, simulated, and fabricated. The measured results agree well with the simulated results. The simulated and measured results indicate that the proposed design can generate reconfigurable multibeam in both forward and backward directions, either separately or simultaneously. In the unidirectional states, forward and backward beam-scanning is achieved within an angular range of
$+/- 30^{\circ }$
and
$+/- 22^{\circ }$
, respectively, with peak gains of 23.6 and 23.1 dBi. A simultaneous forward and backward beam-scanning of
$+/- 40^{\circ }$
and
$+/- 22^{\circ }$
is achieved in the hybrid radiation state, with peak gains of 19.4 and 19.3 dBi, respectively. The proposed antenna array design offers several advantages, including bidirectional low-loss beam-scanning, a simple structure, low power consumption, and a low profile.