3D printed variable aperture horn with modular ridges

Abstract

3D printing technology has significant potential to modernize the student laboratory experience in the area of electromagnetic wave propagation and scattering. In this contribution, a fast and low-cost method to 3D print and metallize a variable aperture horn and waveguide launcher are presented. The launcher converts a SubMiniature version A (SMA) coaxial connector to WR 187 waveguide (standard size of waveguide for 3.95 GHz to 5.85 GHz) and is printed from plastic while being metallized with aluminum tape. The launcher provided similar performance to an off the shelf launcher at one 40th the cost. As a teachable extension to this launcher a variable aperture horn is 3D printed and metallized with aluminum tape. The aperture area of the horn is changed by rotating the E⃗ walls of the horn away from each other by use of pivot in the transition between the launcher and the horn. This horn showed the expected decrease in beamwidth and increase in peak gain as the aperture area was increased while maintaining a usable impedance match. Modular center ridges were also printed to demonstrate the utility of center ridges in a horn antenna without H⃗ walls. Overall, a modular, inexpensive, and easy to construct waveguide system is presented that is useful for teaching electromagnetics specifically the relationship between aperture area and antenna gain, as well as providing a platform for waveguide experiments.