Abstract: Apparatus and techniques are described for monitoring slosh of a liquid within a propellant tank. The approaches described herein can use an electromagnetic transmitter positioned at a first location on or within the tank, the electromagnetic transmitter coupled to a source of electromagnetic energy and arranged to establish a specified electromagnetic field configuration within the tank using a signal from the source, and an electromagnetic receiver positioned at a different second location on or within the tank, the electromagnetic receiver arranged to sense an electromagnetic field established within the tank by the electromagnetic transmitter. A control circuit can be coupled to the electromagnetic receiver, the control circuit configured to determine a characteristic of a spatial configuration of the liquid using the sensed electromagnetic field. The characteristic can include one or more of a position, a quantity, or a spatial distribution of the liquid, as an illustration.

Abstract: Antenna structures can include an additively manufactured engineered fingerprint (AMEF). AMEF antenna features facilitate individual or type classification of an unknown source antenna. As described herein, physical features can be included in an additively manufactured antenna to facilitate source identification, such as without sacrificing antenna performance. In general, AMEF techniques can improve physical layer security, such as without dramatically increasing production cost or decreasing production throughput, as compared to other approaches.

Abstract: Additive manufacturing can include use of a laser-machining technique. Laser machining can be used to form cavities, trenches, or other features in an additively-manufactured structure. Spectroscopy can be performed to monitor a laser machining operation. For example, a laser-enhanced additive manufacturing process flow can include depositing a conductive layer on a surface of a dielectric layer, and conductively isolating a first region from a second region of the conductive layer using ablative optical energy, including applying ablative optical energy to the conductive layer, monitoring a spectrum of an ablative plume generated by applying the ablative optical energy, and controlling the ablative optical energy in response to a characteristic of the spectrum of the ablative plume.

Abstract: A novel polymer optical waveguide and method of manufacturing is presented herein. A digitally manufactured process is described which utilizes a micro-dispensed UV optical adhesive as the contour guiding cladding, a fused deposition modeling technology for creating a core, and a subtractive laser process to finish the two ends of the optical interconnect. The optical waveguide can be printed directly on a circuit board in some embodiments. Alternatively, using a slightly modified process including a step to bond the optical fiber to the substrate, the optical interconnect can be manufactured on a flexible substrate.

Abstract: Apparatus and techniques described herein can include antenna configurations and related fabrication. For example, a Z-axis meandering antenna configuration can be fabricated, such as by forming a dielectric substrate extending in two dimensions and defining an undulating region extending out of a plane defined by the two dimensions; and forming at least one conductive region following a contour of the dielectric substrate including at least a portion of the undulating region. The at least one conductive region can follow the contour of the dielectric substrate, such as including a first conductive region on a first layer, and a second conductive region on another layer separate from the first conductive region of the first conductive layer.

Abstract: Apparatus and techniques are described for monitoring slosh of a liquid within a propellant tank. The approaches described herein can use an electromagnetic transmitter positioned at a first location on or within the tank, the electromagnetic transmitter coupled to a source of electromagnetic energy and arranged to establish a specified electromagnetic field configuration within the tank using a signal from the source, and an electromagnetic receiver positioned at a different second location on or within the tank, the electromagnetic receiver arranged to sense an electromagnetic field established within the tank by the electromagnetic transmitter. A control circuit can be coupled to the electromagnetic receiver, the control circuit configured to determine a characteristic of a spatial configuration of the liquid using the sensed electromagnetic field. The characteristic can include one or more of a position, a quantity, or a spatial distribution of the liquid, as an illustration.

Abstract: Apparatus and techniques described herein can include antenna configurations and related fabrication. For example, a Z-axis meandering antenna configuration can be fabricated, such as by forming a dielectric substrate extending in two dimensions and defining an undulating region extending out of a plane defined by the two dimensions; and forming at least one conductive region following a contour of the dielectric substrate including at least a portion of the undulating region. The at least one conductive region can follow the contour of the dielectric substrate, such as including a first conductive region on a first layer, and a second conductive region on another layer separate from the first conductive region of the first conductive layer.

Abstract: A novel polymer optical waveguide and method of manufacturing is presented herein. A digitally manufactured process is described which utilizes a micro-dispensed UV optical adhesive as the contour guiding cladding, a fused deposition modeling technology for creating a core, additional optical adhesive to complete the cladding and a subtractive laser process to finish the two ends of the optical interconnect.

Abstract: In some embodiments, an apertured waveguide includes a wall comprising a plurality of apertures and an interior channel along which electromagnetic waves can propagate, the interior channel being defined at least in part by the wall.

Abstract: In one embodiment, a radio-frequency identification (RFID) tag includes a substrate having a top surface including first and second ends, a bottom surface, first and second end surfaces, and opposed lateral surfaces, a passive RFID integrated circuit (IC) chip mounted to the top surface of the substrate, a monopole antenna that includes a planar radiating arm that extends out from the RFID IC chip along the top surface of the substrate to the first end of the top surface of the substrate and a matching loop having two grounded matching stubs that surround the chip and a portion of the radiating arm, each matching stub comprising a longitudinal segment that extends along a longitudinal direction of the substrate and a transverse segment that extends along a transverse direction of the substrate along the top surface of the substrate to the radiating arm at a point located between the RFID IC chip and the first end of the top surface, and a ground plane formed on the bottom surface, the second end surface, and

Abstract: In one embodiment, a radio-frequency identification (RFID) tag includes multiple orthogonal substrates, a passive RFID integrated circuit chip mounted to one of the substrates, and a three-dimensional tag antenna electrically connected to the chip and extending to each of the orthogonal substrates.

Abstract: In one embodiment, a radio-frequency identification (RFID) tag including a substrate having a top surface, bottom surface, opposed end surfaces, and opposed lateral surfaces, a passive RFID integrated circuit (IC) chip mounted to the top surface of the substrate, a monopole antenna that includes a planar radiating arm that extends out from the RFID IC chip along the top surface of the substrate and a matching loop having two grounded matching stubs that surround the chip and a portion of the radiating arm, and a ground plane formed on the bottom surface, an end surface, and the top surface of the substrate, the ground plane being electrically coupled to the matching stubs and the radiating arm.