Physics

Microstrip

Birefringence

Beam steering

Light source

Extremely high frequency

Optics

Polarizer

Radiation pattern

Beam (structure)

Circular polarization

Antenna (radio)

Materials science

Ka band

Reflector (photography)

Axial ratio

Computer science

Phased array

Antenna array

Telecommunications

IEEE Transactions on Antennas and Propagation

In this article, a compact and low-profile beam steering circularly polarized folded reflectarray antenna (CPFRA) with low scan loss for wide-angle coverage is proposed and designed. In order to obtain lower scan loss over a wider beam coverage range (BCR), a multibeam optimization method considering the illumination weighting factor is introduced to obtain minimum phase errors for the designed beam direction. To improve antenna compactness and alleviate the mutual couplings among multiple feeding sources, small-size substrate integrated waveguide (SIW) cavity-backed slot antennas are employed as the feeding sources, which are integrated with the single-layer reflector board. An incident-angle-insensitive circular polarizer is designed and integrated over the antenna aperture to achieve circularly polarized (CP) radiation over a wide BCR. Finally, a 15-beam CPFRA working at the Ka-band with a size of 140 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times140$ </tex-math></inline-formula> mm is designed, manufactured, and measured to validate the proposed design method. Measurement results show that the designed CPFRA can achieve a rather flat gain, with only a 2.1 dB scan loss, across the wide 3 dB BCR of ±29°. The good CP beams are formed over the entire coverage range without any blind zone. With the advantages of wide-angle coverage, low scan loss, and high integration, the proposed beam steering antenna is promising in applications such as 5G communication, radar imaging, and target recognition.

A Wide-Angle Coverage and Low Scan Loss Beam Steering Circularly Polarized Folded Reflectarray Antenna for Millimeter-Wave Applications