A method for processing a radar signal based on a photonic fractional Fourier transformer comprises: transmitting a linear frequency modulation signal to targets to be detected, receiving echo signals of the targets to be measured, and loading the linear frequency modulation signal and the echo signals onto a single-frequency optical wave by an electro-optical modulator (S1); respectively biasing a sub-modulator and a parent modulator of the electro-optical modulator at different bias points, modulating the single-frequency optical wave by the electro-optical modulator based on the linear frequency modulation signal and the echo signals, and outputting a modulated optical signal (S2); converting the modulated optical signal by a photoelectric detector to a photocurrent (S3); and performing Fourier transform on the photocurrent to obtain a fractional Fourier spectrum, and obtaining distance information of the targets to be measured according to peak positions of each pulse signal in the fractional Fourier spectrum (S4).

An electronic device may include a voltage standing wave ratio (VSWR) sensor disposed along a radio-frequency transmission line between a signal generator and an antenna. The VSWR sensor may gather VSWR measurements from radio-frequency signals transmitted by the signal generator over the transmission line. Control circuitry may identify a variation in the VSWR measurements over time and may compare the variation to a threshold value to determine whether an external object in the vicinity of the antenna is animate or inanimate. The control circuitry may reduce the maximum transmit power level of the antenna when the external object is animate and may maintain or increase the maximum transmit power level when the external object is inanimate. This may serve to maximize the wireless performance of the electronic device while also ensuring that the device complies with regulatory limits on radio-frequency energy exposure.

An electronic device may include wireless circuitry having a set of two or more antennas coupled to voltage standing wave ratio (VSWR) sensors. The VSWR sensors may gather VSWR measurements from radio-frequency signals transmitted using the set of antennas. The antennas may be disposed on one or more substrates and/or may be formed from conductive portions of a housing. Control circuitry may process the VSWR measurements to identify the ranges between each of the antennas in the set of antennas and an external object. The control circuitry may process the ranges to identify an angular location of the external object with respect to the device. The control circuitry may adjust subsequent communications based, adjust the direction of a signal beam produced by a phased antenna array, identify a user input, or perform any other desired operations based on the angular location.

A low range altimeter (LRA) may include a transmitter, a receiver, at least one antenna, an active leakage cancellation circuit, and a microcontroller unit (MCU). The transmitter may be configured to transmit a first signal (or transmitted signal) via the at least one antenna. The receiver may be configured to receive a second signal (or received signal) via the at least one antenna. The active leakage cancellation circuit may be configured to receive a portion of the transmitted signal from the transmitter, and may be configured to inject the portion of the transmitted signal into the receiver after an adjustment of the portion of the transmitted signal to reduce leakage observed in the received signal. The MCU may be coupled to the transmitter and the receiver, and may be configured to adjust the portion of the portion of the transmitted signal.

A non-contact object and/or gesture detection system includes at least one sensor configured to sense an object or motion within a field of view (FOV) using radio frequency radiation. Various sensor and brackets are provided which may allow a position and/or tilt of the sensor to be adjusted for controlling the FOV. A sensor housing includes a vent filter that breathable but impermeable to liquids. Various antenna designs are provided to provide desired FOV sizes and shapes, particularly for optimizing a radiation pattern that is relatively wide and shallow. A steerable antenna layout is also provided for controlling the location of the FOV without an adjustable bracket. A sensor housing including a projector mount for an icon projector is provided. A seal prevents debris from entering between the antenna and the bumper.

In an embodiment, a method includes: receiving radar signals with a millimeter-wave radar; generating range data based on the received radar signals; detecting a target based on the range data; performing ellipse fitting on in-phase (I) and quadrature (Q) signals associated with the detected target to generate compensated I and Q signals associated with the detected target; classifying the compensated I and Q signals; when the classification of the compensated I and Q signals correspond to a first class, determining a displacement signal based on the compensated I and Q signals, and determining a vital sign based on the displacement signal; and when the classification of the compensated I and Q signals correspond to a second class, discarding the compensated I and Q signals.

Implementations of the present disclosure relate to a radar receiver for a real-valued analog RF radar signal. The radar receiver comprises a quadrature mixer circuit configured to generate, from the real-valued analog RF radar signal, a complex-valued analog signal comprising an inphase (I) signal component and a quadrature (Q) signal component, an analog polyphase filter configured to filter the I- and Q-signal components of the complex-valued analog signal to generate filtered I- and Q-signal components, and an analog-to-digital converter coupled to an output of the analog polyphase filter. The radar receiver is configured to convert only one of the filtered I- and Q-signal components from the analog to the digital signal domain.

In some aspects, a radar device may receive a received signal comprising a reflected frequency modulated continuous wave (FMCW) radar signal and interference. The radar device may identify the reflected FMCW radar signal based at least in part on performing a phase based search procedure to facilitate removing the interference from the received signal. The radar device may perform an action based at least in part on a characteristic of the identified reflected FMCW radar signal. Numerous other aspects are described.

Techniques and apparatuses are described that implement a smart-device-based radar system capable of performing angular estimation using machine learning. In particular, a radar system 102 includes an angle-estimation module 504 that employs machine learning to estimate an angular position of one or more objects (e.g., users). By analyzing an irregular shape of the radar system 102's spatial response across a wide field of view, the angle-estimation module 504 can resolve angular ambiguities that may be present based on the angle to the object or based on a design of the radar system 102 to correctly identify the angular position of the object. Using machine-learning techniques, the radar system 102 can achieve a high probability of detection and a low false-alarm rate for a variety of different antenna element spacings and frequencies.

According to an embodiment, a first device includes: a first transceiver configured to transmit two or more first carrier signals using an output of a first reference signal source and to receive two or more second carrier signals; and a calculation unit, and a second device includes: a second transceiver configured to transmit the two or more second carrier signals using an output of a second reference signal source that operates independently of the first reference signal source and to receive the two or more first carrier signals. A frequency group of the two or more first carrier signals and a frequency group of the two or more second carrier signals are identical or substantially identical to each other, and the calculation unit calculates the distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.