Single-Fed Additively Manufactured Conical Horn Antenna with Circular Polarization for Millimeter-Wave Applications

In this paper, we present a circularly polarized conical horn antenna fed by a standard WR19 waveguide. The antenna was additively manufactured from polymer resin by digital light processing and subsequently electroplated with a thin copper surface finish, which enables the guidance of electromagnetic waves and thus the functionality of the antenna. Both processes are cost effective and time efficient compared to the traditional split-block technique. The performance of the fabricated conical horn antenna is specified by a measured realized gain of 11 - 13.5 dBi over the entire frequency band of interest from 40 - 50 GHzfor circular polarization. This is in high agreement with the simulated gain of 11.3 - 14.2 dBi. The measured reflection coefficient for this frequency range is less than -16.5 dB while the axial ratio remains below 3dB. In simulation, an axial ratio of less than 5dB is reached over the entire Q Band from 40 - 60 GHz. Furthermore, this circularly polarized antenna design, in combination with the flexibility of additive manufacturing and electroplating, can be integrated conveniently with other components and can satisfy various demands for the gain and main lobe width, as well as both left-hand or right-hand circular polarization by slight changes to its geometry.