Search

This CLAS-ACT is a lightweight, active phased array conformal antenna comprised of a thin multilayer microwave printed circuit board built on a flexible aerogel substrate using new methods of bonding. The aerogel substrate enables the antenna to be fitted onto curved surface. NASA's prototype operates at 11-15 GHz (Ku-band), but the design could be scaled to operate in the Ka-band (26 to 40 GHz). The antenna element design incorporates a dual stacked patch for wide bandwidth to operate on both the uplink and downlink frequencies with a common aperture. These elements are supported by a flexible variant of aerogel that allows the material to be thick in comparison to the wavelength of the signal with little to no additional weight. The conformal antenna offers advantages of better aerodynamics for the airframe, and potentially offers more physical area to either broadcast further distances or to broadcast at a higher data rate. The intended application for this antenna is for UAVs that need more than line of sight communications for command and control but cannot accommodate a large satellite dish. Examples may be UAVs intended for coastal monitoring, power line monitoring, emergency response, and border security where remote flying over large areas may be expected. Smaller UAVs may benefit greatly from the conformal antenna. Another possible application is a UAV mobile platform for Ku-band satellite communication. With the expectation that 5G will utilize microwave frequencies this technology may be of interest to other markets outside of satellite communications. For example, the automotive industry could benefit from a light weight conformal phased array for embedded radar. Also, the CLAS-ACT could be used for vehicle communications or even vehicle to vehicle communications.

Advances in additive manufacturing have enabled development of printable electronic sensor elements that can be deposited onto flexible substrates. To benchmark performance of printed sensors against the state of the art, NASA developed a low power flexible sensor platform. The platform integrates the following key components and features: -Flexible substrate: DuPont Kapton allows bending around cylindrical surfaces as small as in diameter. -Embedded microcontroller: Cypress CY8C4248 LQI-BL583 Arm Cortex M0 processor with BLE wireless controller, max frequency 48 MHz. Supports low power modes of operation, capacitive sensing support, and a single-channel 12-bit AD converter. -Commercial sensor suite: Bosch BNO080 inertial sensor; Bosch BME280 humidity, pressure, and temperature sensor; AMS CCS811 air quality sensor (VOCs and CO2). -Prototyping area for custom-printed sensors: 1) thermistor, uses carbon-based PTC resistor paste DuPont2792; 2) capacitive humidity sensor using a NASA-developed dielectric ink. NASA researchers have used the platform to study performance of the printed capacitive humidity sensor. The 2x4 mm co-doped barium titanate sensing element is highly sensitive to water vapor and performs as an unobtrusive breathing monitor, sensitive to breath at distances of up to 20 cm. Average change of sensor capacitance at a distance of 7.5 cm was observed to be 6.23.5 pF.

The DLC platform is composed of three key components: a NASA-designed field programmable gate array (FPGA) board, a NASA-designed multiprocessor on-a-chip (MPSoC) board, and a proprietary datapath that links the boards to available inputs and outputs to enable high-bandwidth data collection and processing. The inertial measurement unit (IMU), camera, Navigation Doppler Lidar (NDL), and Hazard Detection Lidar (HDL) navigation sensors (depicted in the diagram below) are connected to the DLC’s FPGA board. The datapath on this board consists of high-speed serial interfaces for each sensor, which accept the sensor data as input and converts the output to an AXI stream format. The sensor streams are multiplexed into an AXI stream which is then formatted for input to a XAUI high speed serial interface. This interface sends the data to the MPSoC Board, where it is converted back from the XAUI format to a combined AXI stream, and demultiplexed back into individual sensor AXI streams. These AXI streams are then inputted into respective DMA interfaces that provide an interface to the DDRAM on the MPSoC board. This architecture enables real-time high-bandwidth data collection and processing by preserving the MPSoC’s full ability. This sensor datapath architecture may have other potential applications in aerospace and defense, transportation (e.g., autonomous driving), medical, research, and automation/control markets where it could serve as a key component in a high-performance computing platform and/or critical embedded system for integrating, processing, and analyzing large volumes of data in real-time.