A digital FMCW radar is described that simultaneously transmits and receives digitally frequency modulated signals using multiple transmitters and multiple receivers and associated antennas. Several sources of nearby spillover from transmitters to receivers that would otherwise degrade receiver performance are subtracted by a cancellation system in the analog radio frequency domain that adaptively synthesizes an analog subtraction signal based on residual spillover measured by a correlator operating in the receivers' digital signal processing domains and based on knowledge of the transmitted waveforms. The first adaptive cancellation system achieves a sufficient reduction of transmit-receive spillover to avoid receiver saturation or other non-linear effects, but is then added back in to the signal path in the digital domain after analog-to-digital conversion so that spillover cancellation can also operate in the digital signal processing domain to remove deleterious spillover components.

A radar sensing system includes at least one transmitter, at least one receiver and a processor. The at least one transmitter transmits a power shaped RF signal. The transmitted RF signal decreases in power over time. The at least one receiver receives a reflected RF signal. The reflected RF signal is the transmitted RF signal reflected from targets in the environment. The reflected RF signal is down-converted and the result provided to the processor. The processor samples the down-converted reflected RF signal during a plurality of time intervals to produce a sampled stream. The different time intervals of the plurality of time intervals will contain different signal levels of RF signals reflected from the targets. The processor also selects samples in the sampled stream over a selected time interval of the plurality of time intervals that is free of RF signals reflected off of near targets.

A reflected signal detector (12) detects the amplitude and the phase of a reflected signal and outputs detection signals. A control circuit (13) adjusts first control signals and second control signals on the basis of the detection signals. A first cancel signal output portion (9) adjusts a first cancel signal so that the first cancel signal has a phase opposite to that of the reflected signal and has the same amplitude as that of the reflected signal using the first control signals. A second cancel signal output portion (10) adjusts a second cancel signal so that the second cancel signal has a phase opposite to that of a leakage signal and has the same amplitude as that of the leakage signal using the second control signals. A combining portion (11) combines a reception signal including noise signals with the first and second cancel signals.

In a radar system, a cancellation circuit is described for compensating for the effects of spillover between each transmitter and a receiver. The cancellation circuit is configured for applying cancellation signals to the receiver which are generated in a cancellation filter utilizing a primary impulse response characteristic corresponding to the spillover, a signal to be transmitted from each transmitter in the radar system, and a range profile output from the receiver. The cancellation circuit may also include a secondary impulse response characteristic module and a dithering module to improve the sensitivity of the receiver.

A transceiver includes a transmitter, a frequency synthesizer coupled to the transmitter, a receiver coupled to the frequency synthesizer and a voltage sensor; and a digital controller coupled to the voltage sensor, the receiver, and the transmitter, wherein based on a DC voltage measurement of an IF signal made by the voltage sensor, a relative phase adjustment occurs of a relative phase associated with a local oscillator (LO) port and a radio frequency (RF) port of the receiver.

There is provided a radar apparatus comprising: a substrate; multiple antenna elements mounted on the substrate; and a signal-coupling suppressor disposed between the multiple antenna elements.

A radar signal transmitter transmits first and second radar signals at different first and second frequencies. A radar receiver receives reflected radar signals and generates receive signals indicative of the reflected radar signals. A first receive signal is indicative of a first reflected radar signal generated by reflection of the first transmitted radar signal, and a second receive signal is indicative of a second reflected radar signal generated by reflection of the second transmitted radar signal. A processor receives the first and second receive signals and computes a difference between the first and second receive signals to generate a difference signal. The processor processes the difference signal to provide radar information for the region, the processor adjusting at least one of amplitude and phase of at least one of the first and second receive signals such that the difference is optimized at a preselected range from the receiver.

A radar system including a reference channel formed symmetrically in relation to a main channel, with a first oscillator, generating a first input signal, which is feedable to an antenna in the main channel, a reflected portion of the first input signal being feedable to a first mixer, the first input signal in the reference channel being feedable to a second mixer via a second directional coupler, with a second oscillator, generating a second input signal having a frequency differing from the first input signal in a defined way, which is feedable to the first and second mixers, the signal coming from the mixer of the main channel and the signal coming from the mixer of the reference channel being compared, and dimensioning a terminating impedance of the reference channel as a function of the comparison so that the output signals of the main and reference channels have identical properties.

An illustrative example sensor device includes a transmitter and a receiver having at least one lobe and at least null. A cover near the transmitter and the receiver includes a surface facing toward the transmitter and the receiver. The surface is at an angle relative to the receiver to direct at least some radiation transmitted by the transmitter and reflected from the surface toward the at least one null of the receiver.

A radar includes a transmitter that generates a first signal that is a frequency modulated continuous wave (FMCW) signal and radiates the generated first signal to an outside, a receiver that receives a second signal based on the first signal and generates a baseband signal of the second signal, a signal processor that extracts a target frequency signal from the baseband signal, and a signal converter that outputs the target frequency signal that is controlled as a digital signal, and wherein the signal processor includes a high pass filter connected to the receiver, that receives the baseband signal, and attenuates a low frequency signal present in the received baseband signal, based on a first cutoff frequency, an amplifier that amplifies the attenuated baseband signal, and a signal controller that removes a direct current component of the amplified baseband signal, based on a second cutoff frequency.