Abstract: Disclosed active reflector apparatus and methods that inhibit self-induced oscillation. One illustrative apparatus embodiment includes an amplifier and an adjustable phase shifter. The amplifier amplifies a receive signal to generate a transmit signal, the transmit signal causing interference with the receive signal. The adjustable phase shifter modifies the phase of the transmit signal relative to that of the receive signal to inhibit oscillation. A controller may periodically test a range of settings for the adjustable phase shifter to identify undesirable phase shifts prone to self-induced oscillation, and may maintain the phase shift setting at a value that inhibits oscillation.

Abstract: A centralized occupancy detection system enables monitoring of multiple seats, or more generally, multiple stations, with a single sensor. One illustrative vehicle includes: one or more stations each configured to accommodate an occupant of the vehicle, a radar-reflective surface, and a radar transceiver configured to use the radar-reflective surface to detect an occupant of at least one of the stations. Another illustrative vehicle includes: multiple stations to each accommodate an occupant of the vehicle, and a radar transceiver configured to examine each of the multiple stations to determine whether that station has an occupant.

Abstract: A centralized occupancy detection system enables monitoring of multiple seats, or more generally, multiple stations, with a single sensor. One illustrative vehicle includes: one or more stations each configured to accommodate an occupant of the vehicle, a radar-reflective surface, and a radar transceiver configured to use the radar-reflective surface to detect an occupant of at least one of the stations. Another illustrative vehicle includes: multiple stations to each accommodate an occupant of the vehicle, and a radar transceiver configured to examine each of the multiple stations to determine whether that station has an occupant.

Abstract: A radar detection method with receive antenna calibration includes: forming a detection matrix from signals detected by an arrangement of receive antennas in response to chirps transmitted by an arrangement of transmit antennas, the detection matrix having multiple rows corresponding to the chirps, multiple columns corresponding to a sample of the signals, and multiple planes corresponding the receive antennas; deriving a range matrix by performing a frequency transform on a portion of each row of the detection matrix; deriving a velocity matrix by performing a frequency transform on a portion of each column of the range matrix; deriving a direction-of-arrival matrix by performing a frequency transform on a portion of one or more layers of the velocity matrix; analyzing the direction-of-arrival matrix to determine a current peak width; and adjusting, based on the current peak width, phase shifts associated with one or more antennas.

Abstract: Automotive radar systems may employ a reconfigurable connection of antennas to radar transmitters and/or receivers. An illustrative embodiment of an automotive radar system includes: a radar transmitter; a radar receiver; and a digital signal processor coupled to the radar receiver to detect reflections of a signal transmitted by the radar transmitter and to derive signal measurements therefrom. At least one of the radar transmitter and the radar receiver are switchable to provide the digital signal processor with signals from each of multiple combinations of transmit antenna and receive antenna.

Abstract: An integrated circuit may include K transmit circuits that output K transmit signals, where K is a non-zero integer and the K transmit signals are encoded using first Doppler code multiplexing. Moreover, the integrated circuit may include L receive circuits that provide L receive signals (which may correspond to the K transmit signals), where L is a non-zero integer and the L receive signals are encoded using second Doppler code multiplexing. Note that the first and/or the second Doppler code multiplexing may be different from Doppler division multiplexing. Furthermore, the first Doppler code multiplexing may include selectively Doppler shifting a kth transmit signal in the K transmit signals by nk bins between chirps in a frame, and the second Doppler code multiplexing may include selectively Doppler shifting an lth receive signal in the L transmit signals by n1 bins between the chirps in the frame.

Abstract: One illustrative integrated electromagnetic-acoustic sensor includes: a ground plane; a patch antenna above the ground plane to send or receive an electromagnetic (EM) signal having an EM signal frequency; and an array of capacitive micromachined acoustic transducers formed by cavities between the patch antenna and a base electrode to send or receive an acoustic signal having an acoustic signal frequency. One illustrative sensing method includes: driving or sensing a EM signal between a ground plane and a patch antenna; and driving or sensing an acoustic signal between the patch antenna and a base electrode, the base electrode and the patch antenna having an array of capacitive micromachined acoustic transducer cavities therebetween.

Abstract: An integrated circuit that performs testing of a circuit sub-block is described. This integrated circuit may include the circuit sub-block that performs a function, where the circuit sub-block is implemented in an analog domain using analog components and in a digital domain using digital components. Moreover, the integrated circuit may perform the testing of the circuit sub-block using independent testing of individual components in the circuit sub-block instead of testing the function of the circuit sub-block as a whole. Note that the individual components include the analog components and the digital components. In some embodiments, the testing may include functional safety testing.

Abstract: Automotive radar systems may employ a reconfigurable connection of antennas to radar transmitters and/or receivers. An illustrative embodiment of an automotive radar system includes: a radar transmitter; a radar receiver; and a digital signal processor coupled to the radar receiver to detect reflections of a signal transmitted by the radar transmitter and to derive signal measurements therefrom. At least one of the radar transmitter and the radar receiver are switchable to provide the digital signal processor with signals from each of multiple combinations of transmit antenna and receive antenna.

Abstract: Multiple-input multiple-output (MIMO) radar systems are equipped with channel extenders to further increase the number of receive and/or transmit antennas that can be supported by a given radar transceiver. One illustrative radar system includes: a radar transceiver to generate a transmit signal and to downconvert at least one receive signal; and a receive-side extender that couples to a set of multiple receive antennas to obtain a set of multiple input signals, that adjustably phase-shifts each of the multiple input signals to produce a set of phase-shifted signals, and that couples to the radar transceiver to provide the at least one receive signal, the at least one receive signal being a sum of the phase-shifted signals. An illustrative receive-side extender includes: multiple phase shifters each providing an adjustable phase shift to a respective input signal; a power combiner that forms a receive signal by combining outputs of the multiple phase shifters.

Abstract: One illustrative integrated electromagnetic-acoustic sensor includes: a ground plane; a patch antenna above the ground plane to send or receive an electromagnetic (EM) signal having an EM signal frequency; and an array of capacitive micromachined acoustic transducers formed by cavities between the patch antenna and a base electrode to send or receive an acoustic signal having an acoustic signal frequency. One illustrative sensing method includes: driving or sensing a EM signal between a ground plane and a patch antenna; and driving or sensing an acoustic signal between the patch antenna and a base electrode, the base electrode and the patch antenna having an array of capacitive micromachined acoustic transducer cavities therebetween.

Abstract: An improved circuit configuration is disclosed for calibrating and/or verifying the operation of phase shifters in a phased array radar system. In one illustrative embodiment, a method includes: (i) programming a set of phase shifters to convert a radio frequency signal into a set of channel signals; (ii) splitting off a monitor signal from each channel signal while coupling the set of channel signals to a set of antenna feeds; and (iii) while taking the monitor signals in pairs associated with adjacent channels, measuring a relative phase between each pair of monitor signals.

Abstract: Disclosed active reflector apparatus and methods that inhibit self-induced oscillation. One illustrative apparatus embodiment includes an amplifier and an adjustable phase shifter. The amplifier amplifies a receive signal to generate a transmit signal, the transmit signal causing interference with the receive signal. The adjustable phase shifter modifies the phase of the transmit signal relative to that of the receive signal to inhibit oscillation. A controller may periodically test a range of settings for the adjustable phase shifter to identify undesirable phase shifts prone to self-induced oscillation, and may maintain the phase shift setting at a value that inhibits oscillation.

Abstract: A centralized occupancy detection system enables monitoring of multiple seats, or more generally, multiple stations, with a single sensor. One illustrative vehicle includes: one or more stations each configured to accommodate an occupant of the vehicle, a radar-reflective surface, and a radar transceiver configured to use the radar-reflective surface to detect an occupant of at least one of the stations. Another illustrative vehicle includes: multiple stations to each accommodate an occupant of the vehicle, and a radar transceiver configured to examine each of the multiple stations to determine whether that station has an occupant.

Abstract: Multiple-input multiple-output (MIMO) radar systems are equipped with channel extenders to further increase the number of receive and/or transmit antennas that can be supported by a given radar transceiver. One illustrative radar system includes: a radar transceiver to generate a transmit signal and to downconvert at least one receive signal; and a receive-side extender that couples to a set of multiple receive antennas to obtain a set of multiple input signals, that adjustably phase-shifts each of the multiple input signals to produce a set of phase-shifted signals, and that couples to the radar transceiver to provide the at least one receive signal, the at least one receive signal being a sum of the phase-shifted signals. An illustrative receive-side extender includes: multiple phase shifters each providing an adjustable phase shift to a respective input signal; a power combiner that forms a receive signal by combining outputs of the multiple phase shifters.

Abstract: Disclosed active reflector apparatus and methods that inhibit self-induced oscillation. One illustrative apparatus embodiment includes an amplifier and an adjustable phase shifter. The amplifier amplifies a receive signal to generate a transmit signal, the transmit signal causing interference with the receive signal. The adjustable phase shifter modifies the phase of the transmit signal relative to that of the receive signal to inhibit oscillation. A controller may periodically test a range of settings for the adjustable phase shifter to identify undesirable phase shifts prone to self-induced oscillation, and may maintain the phase shift setting at a value that inhibits oscillation.

Abstract: A centralized occupancy detection system enables monitoring of multiple seats, or more generally, multiple stations, with a single sensor. One illustrative vehicle includes: one or more stations each configured to accommodate an occupant of the vehicle, a radar-reflective surface, and a radar transceiver configured to use the radar-reflective surface to detect an occupant of at least one of the stations. Another illustrative vehicle includes: multiple stations to each accommodate an occupant of the vehicle, and a radar transceiver configured to examine each of the multiple stations to determine whether that station has an occupant.

Abstract: Automotive radar systems may employ a reconfigurable connection of antennas to radar transmitters and/or receivers. An illustrative embodiment of an automotive radar system includes: a radar transmitter; a radar receiver; and a digital signal processor coupled to the radar receiver to detect reflections of a signal transmitted by the radar transmitter and to derive signal measurements therefrom. At least one of the radar transmitter and the radar receiver are switchable to provide the digital signal processor with signals from each of multiple combinations of transmit antenna and receive antenna.

Abstract: A radar antenna calibration method includes: forming a detection matrix from signals detected by an arrangement of receive antennas in response to chirps transmitted by an arrangement of transmit antennas, the detection matrix having multiple rows corresponding to the chirps, multiple columns corresponding to a signal sample, and multiple planes corresponding the receive antennas; deriving a range matrix by performing a frequency transform on a portion of each row of the detection matrix; extracting a slice of the range matrix, with different rows of the slice being associated with different chirps and with different receive antennas; deriving a velocity matrix from the extracted slice by performing a frequency transform on a portion of each column of the extracted slice; analyzing the velocity matrix to determine a current peak width; and adjusting, based on the current peak width, phase shifts associated with one or more of the receive antennas.

Abstract: A receive extender in an integrated circuit may include: N phase-adjustment circuits that adjust phases of N receive signals from N receive antennas; and an N:1 demultiplexer that coherently combines the N receive signals into an output signal, which is provided to the transceiver chip. Moreover, a transmit extender in the integrated circuit may include: a 1:M multiplexer that coherently separates a transmit signal from the transceiver chip into M transmit signals, where N and M are non-zero integers that may be different; and M phase-adjustment circuits that adjust phases of the M transmit signals, which are provided to M transmit antennas. Note that the integrated circuit may be coupled to a second integrated circuit that phase shifts the output signal and the transmit signal based at least in part on the oscillator signal. Moreover, control signals between the integrated circuit and the second integrated circuit may be synchronized.