Low-Profile 3D Printed Transmit-array for Wide-Angle Beam Scanning at Ka-Band

Abstract

In this work, we propose a general technique to address the design of low-profile (F/D<0.4) TA antennas with wide-angle beam scanning performance. This approach is based on an iteratively modified phase distribution that allows to average the phase aberrations as a result of the feed displacement among the different outgoing beams. To validate the design process, a prototype based on dielectric unit cells is fabricated and measured, allowing us to take advantage of additive manufacturing (AM) to reach a cost-effective solution in Ka-band. For this, the antenna is composed of a perforated dielectric slab of PLA fed by an open-ended waveguide (WR28) placed at a distance of 47.5 mm, reaching an F/D near to 0.34. The result is an ultra-compact antenna and easy to manufacture. The prototype scan performance goes up to 50°, preserving the SLL below 10 dB, and scanning loss better than 1.5 dB at the central frequency of 29.5 GHz. Moreover, the dielectric implementation of the TA provides broadband operation demonstrating that the design technique is still effective for large operational bandwidth, in this case from 29 to 31 GHz.