Additive manufacturing and conformal integration of radiofrequency connectors and baluns
Date
2022
Authors
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Publisher
University of Delaware
Abstract
Designing low cost, broadband, and wide scan angle beamforming systems is critical for a diverse range of commercial and military applications. Many current beamforming approaches involve complex phased arrays or mechanically steered antennas. The phased arrays are often prohibitively expensive while the mechanically steered systems are often too slow, heavy, and susceptible to mechanical failure. An alternative approach involves the use of graded index (GRIN) RF lenses, such as the Luneburg lens, as passive beamformers. The problem that still exists with the Luneburg lens is they lack wide-angle steering and efficient conformal feed structures needed for some applications. In this thesis, I describe how additive manufacturing (AM) can be leveraged to realize an array of conformal feeds. With the combination of integrated feeds and a spherical Luneburg lens, ultra-wide scan angles are achievable. To realize a fully integrated feed I will describe the design and fabrication of an integrated beam steering device that combines: (1) printed conformal RF connectors, (2) printed broadband baluns, (3) printed broadband antennas, and (4) a Luneburg Lens. ☐ The printed connectors are necessary to be able to transition from Commercial-Off-The-Shelf (COTS) components to the printed structures. Using COTS components often negates the advantages offered by AM which include the ability to create compact footprints and conformal integration into a substrate. For that reason, printed SMA connectors were designed and fabricated to be mechanically robust and achieve low insertion losses up to 18 GHz. ☐ To transition from the printed SMA connector to the radiating element, an impedance transforming balun is required. To that end, a novel, triple-tapered coaxial balun was designed and fabricated using AM. This device exhibits wideband impedance matching properties within the X- and Ku-bands with relatively low insertion losses. To create a conformal array, a new modular approach was explored that allows for the printed feeds to be reconfigured into shapes that conform to the surface of the graded index beam steering lenses. Combining the AM conformal feeds and Luneburg lens, results show beam steering at angles up to ± 70 degrees over the entire Ku-band.
Description
Keywords
Conformal RF connectors, Broadband baluns, Broadband antennas