The integration of additive manufacturing direct-writing technologies with injection molding provides a novel method to combine functional features into plastic products, and could enable mass-manufacturing of custom-molded plastic parts. In this work, direct-write technology is used to deposit conductive ink traces on the surface of an injection mold. After curing on the mold surface, the printed trace is transferred into the plastic part by exploiting the high temperature and pressure of a thermoplastic polymer melt flow. The transfer of the traces is controlled by interlocking with the polymer system, which creates strong plastic/ink interfacial bonding. The hybrid process chain uses designed mold/ink surface interactions to manufacture stable ink/polymer interfaces. Here, the process chain is proposed and validated through systematic interfacial analysis including feature fidelity, mechanical properties, adhesion, mold topography, surface energy, and hot polymer contact angle.

True time delay digital beamforming enables large squint-free bandwidths and high beamcounts, ideal for Low Earth Orbit (LEO) satellite communication links. This work proposes a true time delay architecture using Variable Fractional Delay (VFD). True time delay eliminates many analog beamforming performance constraints including inaccurate beam steering and limited beamcounts, while managing system quantization error. This article presents a method of implementing true time delay using a VFD digital filter with sufficient time resolution to minimize quantization error and enable both gigahertz bandwidths and sampling frequencies. Simulations of antenna patterns utilizing the proposed VFD digital filters demonstrate satisfactory LEO beamforming performance with only a 29-tap filter. The VFD filter was implemented using a Xilinx Virtex Ultrascale FPGA and demonstrated a 1077% reduction in dynamic power and a minimum 498% reduction in logic resources, with only a modest increase in multipliers required when compared to Farrow-based architectures previously proposed in the literature.

As additively manufactured radio frequency (RF) design expands towards higher frequencies, performance becomes ever more sensitive to print-induced dimensional variations. These slight deviations from design dimensions typically skew RF performance, resulting in low yields or poor device performance. In order to overcome this limitation, RF design paradigms must be developed for non-uniform process and material-specific variations. Therefore, a new generalized approach is developed to explore variation-tolerant designs for printed RF structures. This method evaluates the feature fidelity and S11 performance of micro-dispensed, X-band (8–12 GHz) patch antennas by evaluating the standard deviation in as-printed features, surface roughness, and thickness. It was found that the traditional designs based on optimal impedance matching values did not result in the most robust performance over multiple printing sessions. Rather, performance bounds determined by print deviation could be utilized to improve large-batch S11 results by up to 7 dB. This work demonstrates that establishing the average standard deviation of printed dimensions in any RF printing system and following the formulated design procedure could greatly improve performance over large datasets. As such, the method defined here can be applied to improve large-scale, printed RF yields and enable predictive performance metrics for any given printing method.

Additive manufacturing has enabled multifunctional structures, sensors, devices, and platforms to be used in a multitude of fields