A Ka-Band Broadband Polyjet 3-D Printed Quasi-Planar End-Fire Antenna With Partially Hollowed Substrate and Gain Compensation

Abstract

This letter presents a new class of millimeter-wave broadband quasi-planar end-fire antenna featuring flexible design and enhanced structural compatibility with additive manufacturing technology. The broadband end-fire radiation performance is enabled by a coupling-probe-fed rectangular patch that is vertically attached to the sidewall of dielectric substrate of the antenna. The patch and ground of the antenna are perpendicular to the plane of the feeding transmission line and the metal parts of the antenna are embedded into the dielectric substrate. The architecture allows excitation of vertically polarized patterns of the patch. More significantly, the dielectric substrate is hollowed selectively to improve the realized gain in the main-lobe orientation, thus enhancing stability of the radiation patterns in a wide operational bandwidth. A <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band prototype of the proposed antenna is shaped into a 3-D-printing-compatible geometry and is monolithically integrated by exploiting high-precision Polyjet 3-D printing process. The manufactured antenna demonstrates good radiation patterns in a −10-dB impedance bandwidth from 28.8 to 37.0 GHz with in-band realized gains of 2.5–5.0 dBi.