Zachary J. Larimore

We present the design and characterization of fully additively manufactured (AM) SubMiniature version A (SMA) connectors for use up to 18 GHz. Three-dimensional printed connectors can be directly integrated into the radio-frequency (RF) circuit without post-process bonding and can be fabricated into unusual shapes. The flexibility this affords in the manufacturing process offers significant advantages, especially for applications that need to meet strict size and volume constraints. To that end, we describe modifications to the traditional SMA design that better enable AM fabrication. A variety of different connector geometries were printed and fully characterized both electromagnetically and mechanically. Experimental measurements up to 18 GHz demonstrated good RF performance with low insertion losses (< 0.5 dB). Mechanical testing showed that the printed connectors could withstand up to 4.5 kg of direct force for extended periods of time without damage to the printed threads or other connector parts. Additionally, the printed connectors demonstrated good RF performance after repeated use.

We demonstrate a new method for realizing Luneburg lens antennas with nearly continuously graded permittivity profiles in three dimensions. The method combines fused filament fabrication, a nearly ubiquitous additive manufacturing technique, with an effective media approach that employs space-filling curves. We experimentally validate our design methodology by fabricating and characterizing two Luneburg lenses designed to operate at separate frequency bands (26–40 GHz and 70–110 GHz) with antenna gains of 20 and 24 dBi, respectively. The results demonstrate good agreement with rigorous electromagnetic simulations. We also demonstrate the ability to passively beam steer over a wideband of operation (26–40 GHz and 70–110 GHz) with less than 0.5% power loss due to dielectric material losses within the Luneburg lens.

Additive manufacturing (AM) systems are capable of creating complex geometries that are difficult to fabricate using conventional manufacturing methods. While AM techniques are becoming increasingly advanced and accessible to broad set of users, the bottleneck for many electromagnetic applications is the lack of suitable materials. In this presentation we will describe a new magnetodielectric ink developed specifically for microdispensing based AM. Using this new material a miniaturized slotted patch antenna was designed and fabricated using a microdispensing AM platform. Computational and experimental results will be presented.

We describe organic aerogels derived from multifunctional isocyanates through reaction with water (polyureas), acid andydrides (polyimides) and carboxylic acids (polyamides). All processes are invariably single-step, one-pot and take place at room or slightly elevated temperatures. The resulting materials are robust, their density may vary over a very wide range and their nanomorphology can be either particulate or fibrous, but in all cases they all consist of similarly sized primary particles.