In an embodiment, an antenna includes a one-dimensional array of antenna cells, a signal feed, and signal couplers. The antenna cells are each spaced from an adjacent antenna cell by less than one half a wavelength at which the antenna cells are configured to transmit and to receive, are configured to generate an array beam that is narrower in a dimension than in an orthogonal dimension, and are configured to steer the array beam in the dimension. And the signal couplers are each configured to couple a respective one of the antenna cells to the signal feed in response a respective control signal having an active level. For example, the antenna cells can be arranged such that a straight line intersects their geometric centers.

The disclosure provides a radar apparatus for estimating a position and a velocity of a plurality of obstacles. The radar apparatus includes a slave radar chip. A master radar chip is coupled to the slave radar chip. The master radar chip includes a local oscillator that generates a transmit signal. The slave radar chip receives the transmit signal on a first path and sends the transmit signal back to the master radar chip on a second path. A delay detect circuit is coupled to the local oscillator and receives the transmit signal from the slave radar chip on the second path and the transmit signal from the local oscillator. The delay detect circuit estimates a routing delay from the transmit signal received from the slave radar chip on the second path and from the transmit signal received from the local oscillator.

Multi-input downconversion mixers, systems, and methods are provided with input switching in the intermediate frequency or baseband domain. One illustrative mixer embodiment includes: multiple differential pairs of transistors and multiple pairs of switches. Each differential transistor pair has their bases or gates driven by a differential reference signal, their emitters or sources connected to a common node having a current or voltage driven based on a respective one of multiple receive signals, and their collectors or drains providing a product of the differential reference signal with the respective one of the multiple receive signals. Each of the switch pairs selectively couples differential output nodes to the collectors or drains of a respective one of the multiple differential pairs, enabling the differential output nodes to convey an output signal that is a sum of products from selected ones of the multiple differential pairs.

Radar circuitry can include an isolator and a mixer. The isolator can isolate a transmission signal path and a reception signal path from each other, and generate a mixing (e.g. oscillation) signal based on a transmission signal. The isolator can be coupled to the mixer such that the drive signal drives the mixer (e.g. serves as the local oscillation signal of the mixer). The mixer mixes a received signal and the drive signal to generate a converted signal (e.g. a down-converted signal). The isolator can be a hybrid transformer or electrically balanced duplexer.

Device for determining the mixing ratio of a mixture of at least two different fluids, the device comprising: a pipe section with a measuring region; wherein the mixture flows through the measuring region; a radar sensor system with a radar sensor chip arranged on an outer wall of the pipe section. The radar sensor system is configured to: irradiate frequency-modulated millimeter-radar waves (f.sub.S) in a specified frequency range (f) into the measuring region; receive millimeter-radar waves (f.sub.R) backscattered by the mixture; determine a frequency-dependent reflection coefficient (.sub.f) for the specified frequency range (f) using the backscattered millimeter-radar waves (f.sub.R); and calculate or allocate the mixing ratio from the determined frequency-dependent reflection coefficient (.sub.f).

Radar transmitter includes a plurality of transmit antennas that transmit a plurality of transmission signals using a multiplexing transmission, and a transmission circuit. The transmission circuit applies phase rotation amounts corresponding to combinations of Doppler shift amounts and code sequences to the plurality of transmission signals. Each of the combinations of the Doppler shift amounts and the code sequences has at least one different from other combination. The number of multiplexes of the code sequence corresponding to at least one of the Doppler shift amounts in the combinations is different from the number of multiplexing of code sequences corresponding to the remaining Doppler shift amounts.

A radar unit (400) for detecting an existence of interference is described that includes: a millimetre wave (mmW) transceiver (Tx/Rx) circuit configured support a normal data acquisition mode of operation that comprises transmitting a radar signal waveform and receiving an echo signal thereof; a mixed analog and baseband circuit operably coupled to the mmW Tx/Rx circuit; and a signal processor circuit (452) operably coupled to the mixed analog and baseband circuit. An interference detection unit (448) is operably coupled to the mmW Tx/Rx circuit. The radar unit is configured to operate a time-discontinuous mode of operation that includes a first time portion used as an interference monitoring period and a second time portion used by the radar unit in the normal data acquisition mode of operation, whereby the mixed analog and baseband circuit, signal processor circuit (452) and interference detection unit (448) are configured to detect interference signals during the monitoring period.

In a ranging module, a first calculator calculates a distance from a processed signal corresponding to a current pixel. A determiner determines whether the distance calculated by the first calculator differs from a preset limit distance. A re-extractor is configured to, in response to the determiner determining that the distance differs from the preset limit distance, extract pieces of data of processing sections each corresponding to a sweep time of a transmission wave from a time-series of the processed signals saved in a data storage corresponding from a pixel previous to the current pixel in a scanning direction of a scanner to the current pixel while shifting the processing sections one after the other by a time period shorter than the sweep time. A second calculator calculates the distance from the data of each processing section extracted by the re-extractor.

Radar circuitry can include an isolator and a mixer. The isolator can isolate a transmission signal path and a reception signal path from each other, and generate a mixing (e.g. oscillation) signal based on a transmission signal. The isolator can be coupled to the mixer such that the drive signal drives the mixer (e.g. serves as the local oscillation signal of the mixer). The mixer mixes a received signal and the drive signal to generate a converted signal (e.g. a down-converted signal). The isolator can be a hybrid transformer or electrically balanced duplexer.

Multi-input downconversion mixers, systems, and methods are provided with input switching in the intermediate frequency or baseband domain. One illustrative mixer embodiment includes: multiple differential pairs of transistors and multiple pairs of switches. Each differential transistor pair has their bases or gates driven by a differential reference signal, their emitters or sources connected to a common node having a current or voltage driven based on a respective one of multiple receive signals, and their collectors or drains providing a product of the differential reference signal with the respective one of the multiple receive signals. Each of the switch pairs selectively couples differential output nodes to the collectors or drains of a respective one of the multiple differential pairs, enabling the differential output nodes to convey an output signal that is a sum of products from selected ones of the multiple differential pairs.