Abstract: Aircraft sensors are described which record a condition of interest of the aircraft during flight without being powered. The sensor may include a sensing element comprising a nanostructure material which permanently changes state in connection with a permanent change in state of the aircraft, thus recording the condition of the aircraft. When the aircraft is on the ground, the recorded condition is read from the sensor using a wireless radio frequency (RF) reader, rather than communicating the recorded state during flight. In this manner, the sensor operates without interfering with the aircraft while in flight.

Abstract: Corrosion sensors are described. The corrosion sensors may include components formed from carbon nanotube structures and a corroding element formed of a material which corrodes more quickly than a target material being monitored by the corrosion sensor. The corroding material may be exposed to the environment to which the target material being monitored is exposed. The corrosion sensor may be passive, thus consuming little power.

Abstract: Flexible antennas for harvesting electromagnetic energy are described. The flexible antenna may be a far field antenna and may comprise a flexible substrate, a first metal layer disposed on one side of the flexible substrate, and a second metal layer disposed on an opposite side of the flexible substrate. The first and second metal layers may be connected through one or more vias. The first metal layer may be sized to capture electromagnetic energy at a frequency in an ISM band.

Abstract: A wireless charging network system is disclosed that includes wirelessly charged sensor nodes. The wireless network system can include a gateway node configured to aggregate data from sensor nodes within a coverage area of the gateway node. The gateway node is further configured to wirelessly transmit power to the sensor nodes using a beamformed signal, wherein the gateway node adjusts the beamformed signal to maximize wireless power transfer to sensor nodes within each sector of the coverage area. Location information can be used to adjust the beamformed signal. For example, in various embodiments, the gateway node includes a beamformer sector profile table that defines channel adaptive beam profiles for the beamformed signal for each sector of the coverage area. The gateway node can use location information to define the beam profiles.

Abstract: According to various aspects, systems and methods are provided for secure communication between a passive sensor node and a reader. A passive sensor node may be used for monitoring in a variety of situations. A reader may power the passive sensor while communicating with the passive sensor. In some scenarios, it may be necessary or desirable to provide security between the passive sensor and the reader. According to one aspect, the reader may send a first message initiating communication with the passive sensor, which may respond with a second message including encrypted data. An authorized reader may decrypt the data and respond with data encrypted based on the second message in a third message, which may be used by the device to authenticate the reader.

Abstract: Corrosion sensors are described. The corrosion sensors may include components formed from carbon nanotube structures and a corroding element formed of a material which corrodes more quickly than a target material being monitored by the corrosion sensor. The corroding material may be exposed to the environment to which the target material being monitored is exposed. The corrosion sensor may be passive, thus consuming little power.

Abstract: A passive wireless sensor system is disclosed that includes components fabricated from carbon nanotube (CNT) structures. In some situations, the passive wireless sensor system includes a CNT structure sensor and an antenna that communicates wirelessly by altering an impedance of the antenna. The passive wireless sensor system includes a non-battery-powered energy storage device that harvests energy from carrier signals received at the antenna. The antenna and the energy storage device can be formed from CNT structures.

Abstract: Flexible antennas for harvesting electromagnetic energy are described. The flexible antenna may be a far field antenna and may comprise a flexible substrate, a first metal layer disposed on one side of the flexible substrate, and a second metal layer disposed on an opposite side of the flexible substrate. The first and second metal layers may be connected through one or more vias. The first metal layer may be sized to capture electromagnetic energy at a frequency in an ISM band.

Abstract: A wireless network power distribution and data aggregation system, along with associated applications, is disclosed. An exemplary system for wirelessly transmitting power to radio frequency (RF) energy harvesting sensor nodes of a wireless network system includes a pyramid-structured antenna array for wirelessly powering RF energy harvesting sensor nodes within a defined coverage area of the wireless network system. The pyramid-structured antenna array generates a radiation pattern from an orthogonal spread-spectrum signal that minimizes destructive interference between adjacent antennas of the antenna array. Each antenna of the antenna array can wirelessly transmit power to a respective sector of the defined coverage are.

Abstract: Apparatus and method for quadrature error correction for narrowband or tone signal are disclosed. An analog circuit receives a modulated signal and processes in-phase signal and quadrature-phase signal in in-phase and quadrature-phase signal paths respectively. A digital signal processor performs discrete Fourier transform on each of the in-phase and quadrature-phase signals and determines statistical parameters responsive to mismatch characteristics to estimate quadrature error correction.

Abstract: One example embodiment provides a system, apparatus, and method for using polynomial models in tone calibration for quadrature error correction in I/Q receivers. In one example embodiment, method for calibrating an I/Q receiver is provided and includes receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.

Abstract: A wireless charging platform for a wireless sensor network is disclosed, which includes a radio frequency energy distributor and data aggregator (REDDA) system configured to aggregate data from sensor nodes and wirelessly transmit power to the sensor nodes using a beamformed RF signal. The REDDA system can set a radiation pattern for the beamformed RF signal that maximizes RF energy transfer to the sensor nodes based on an environment associated with the sensor nodes. In various embodiments, the REDDA system can include an Internet of Things (IoT) interface connected to an IoT network, and the REDDA system can use information gleaned from the IoT network to set the radiation pattern.

Abstract: A wireless charging network system is disclosed that includes wirelessly charged sensor nodes. The wireless network system can include a gateway node configured to aggregate data from sensor nodes within a coverage area of the gateway node. The gateway node is further configured to wirelessly transmit power to the sensor nodes using a beamformed signal, wherein the gateway node adjusts the beamformed signal to maximize wireless power transfer to sensor nodes within each sector of the coverage area. Location information can be used to adjust the beamformed signal. For example, in various embodiments, the gateway node includes a beamformer sector profile table that defines channel adaptive beam profiles for the beamformed signal for each sector of the coverage area. The gateway node can use location information to define the beam profiles.

Abstract: A transmission system may include a transformer, an adder, an encoder, and a transmitter. The transformer may segment and transform a data packet into segments. The adder may add a check code to each of the segments. The encoder may encode error correction to each of the segments with the added check code. A receiving system may include a receiver, a decoder, a checker, and a selector decoder. The decoder may decode error correction in each of the encoded segments. The checker may check the check code of the error corrected segments. The selector decoder may select at least one of the valid segments based upon the check code and transform the selected segments into a data packet.

Abstract: Apparatus and method for quadrature error correction for narrowband or tone signal are disclosed. An analog circuit receives a modulated signal and processes in-phase signal and quadrature-phase signal in in-phase and quadrature-phase signal paths respectively. A digital signal processor performs discrete Fourier transform on each of the in-phase and quadrature-phase signals and determines statistical parameters responsive to mismatch characteristics to estimate quadrature error correction.

Abstract: A modulation scheme for long range transceiver utilizing a processing scheme in combination with a Hadamard transform is disclosed. The processing scheme can correspond to an industry standard or to other processing schemes. An input signal is parallelized through serial to parallel conversion. The processed parallel signals are orthogonalized using a Hadamard transform to allow multiple channel signals with increased throughput. Accordingly, the long range modulation scheme of this invention can achieve high efficiency and increased throughput while meeting performance goals of long range signal transmission.

Abstract: A transmission system may include a transformer, an adder, an encoder, and a transmitter. The transformer may segment and transform a data packet into segments. The adder may add a check code to each of the segments. The encoder may encode error correction to each of the segments with the added check code. A receiving system may include a receiver, a decoder, a checker, and a selector decoder. The decoder may decode error correction in each of the encoded segments. The checker may check the check code of the error corrected segments. The selector decoder may select at least one of the valid segments based upon the check code and transform the selected segments into a data packet.

Abstract: An electrical circuit includes a local oscillator configured to generate a first reference signal and a second reference signal having a predetermined phase shift with the first reference signal, an I-channel mixer configured to inject the first reference signal to an incoming signal and generate a first output, a compensation mixer configured to multiply the first output with a constant factor to generate a second output, a first low pass filter configured to approximately attenuate frequencies in the second output to generate a third output, and a first correcting filter configured to filter the third output to generate a fourth output. The first correcting filter is configured to reduce a channel impulse response mismatch between the first low pass filter and a second low pass filter, which is configured to attenuate frequencies in a Q-channel of the incoming signal. In specific embodiments, the phase shift includes 45°.

Abstract: An electrical circuit includes a local oscillator configured to generate a first reference signal and a second reference signal having a predetermined phase shift with the first reference signal, an I-channel mixer configured to inject the first reference signal to an incoming signal and generate a first output, a compensation mixer configured to multiply the first output with a constant factor to generate a second output, a first low pass filter configured to approximately attenuate frequencies in the second output to generate a third output, and a first correcting filter configured to filter the third output to generate a fourth output. The first correcting filter is configured to reduce a channel impulse response mismatch between the first low pass filter and a second low pass filter, which is configured to attenuate frequencies in a Q-channel of the incoming signal. In specific embodiments, the phase shift includes 45°.

Abstract: One example embodiment provides a system, apparatus, and method for using polynomial models in tone calibration for quadrature error correction in I/Q receivers. In one example embodiment, method for calibrating an I/Q receiver is provided and includes receiving a first mismatch parameter indicating a mismatch between I and Q channels of the I/Q receiver; and estimating a second mismatch parameter from the first mismatch parameter using a polynomial model.