Laser Formed Fabrication of Conformal and Non-Conformal Millimeter and sub-millimeter Wave Antennas

Laser forming is a process that doesn’t strictly fall into the category of either additive or subtractive manufacturing.  While 3D Additive Manufacturing (AM) technology has had some success in fabricating antennas, there have been various drawbacks limiting performance. For direct-write antennas, antenna performance has been somewhat limited because the resistivity achieved so far with nanoparticle inks is 2-4 times the resistivity of bulk metals. Antennas have also been fabricated by laser powder bed technology, but this technology requires an appreciable investment in equipment, has health issues associated with powders, and some fabricated antennas have exhibited roughness that can impact performance whereby a post-process machining step is required. When combined with laser cutting and welding, the recent work by ARL in laser folding and origami metal working opens up new possibilities for manufacturing antennas using a variety of sheet metals with high fabrication precision and bulk metal conductivity, as required for mm-wave antennas. Millimeter wave antennas require small features because the free-space wavelength is on the order of a few millimeters (f=30-300 GHz « l =10-1mm).  In addition to bending/forming by CW or nanosecond pulse lasers, femtosecond laser pulses can be used for high precision milling, cutting, and micro-adjustments. We propose to determine a library of laser/beamforming parameters to enable laser forming, cutting, and welding of copper, steel, aluminum, and brass. Fortunately, for laser forming and welding, we will not be starting from scratch on this effort because there are already numerous reports in the literature on laser forming, both experimental and modelling.  We also propose to incorporate this library into our DDM-1 ecosystem that includes COTS software with a sheet metal CAD/CAM function as well as laser-toolpath generation; explore the technical merit of laser-forming fabrication of millimeter wave and sub millimeter wave antennas; design and simulate mm-wave and s-mm-wave antennas; fabricate proof-of concept antennas and collaborate with a government partner for evaluation; and move to identify a commercialization roadmap - both within and without our DDM-1 system (we believe within is straight-forward). Our DDM-1 system enables rapid development of the process to allow the antenna technology developer to move a design from a computational electromagnetic modeling tool to our CAD/CAM system for controlling the laser for bending, cutting, and welding. This facilitates rapid on-site prototyping of conformal and non-conformal antennas. For proof of concept in Phase I, we will design, simulate, and laser-fabricate a shunt slot array antenna at S or C band to demonstrate basic capability. For proof of concept in the Phase I option period, we will develop 5-axis fabrication processes and fabricate a 3D conical sinuous antenna.