Abstract: An antenna system, such as a radar antenna system, includes an array of antenna elements and a controller. The controller outputs an in-path indicator in response to an angle of arrival for a target being less than a threshold angle for a given range to the target. The angle of arrival is based on a differential phase angle derived from data defining first and second composite signal returns from the target associated with first and second apertures respectively, and a phase center offset between the apertures. The first and second apertures are formed from first and second subsets of the antenna elements respectively.

Abstract: A homodyne radar system includes a mixer that outputs a signal having a mixer output frequency that is a frequency difference between two input signals. When the frequency difference is small, low frequency noise may mask the actual signal. A variable phase shifter is added to one of the mixer inputs to change the phase at a predetermined rate of change. The phase shifter shifts the frequency of the input signal so that the mixer output frequency is offset by the predetermined rate. The low frequencies are mapped to frequencies that are above the noise frequencies. The phase shift may be achieved by adding a constant phase at predetermined time intervals. The sampling frequency for the resulting signal may need to be increased to accommodate the higher frequencies.

Abstract: An antenna system, such as a radar antenna system, includes an array of antenna elements and a controller. The controller outputs an in-path indicator in response to an angle of arrival for a target being less than a threshold angle for a given range to the target. The angle of arrival is based on a differential phase angle derived from data defining first and second composite signal returns from the target associated with first and second apertures respectively, and a phase center offset between the apertures. The first and second apertures are formed from first and second subsets of the antenna elements respectively.

Abstract: A system includes an antenna having a substrate and a plurality of antenna elements disposed on the substrate. A processing device is configured to measure an aperture function across an aperture of the antenna and determine whether at least one of the antenna elements is blocked based at least in part on the measured aperture function.

Abstract: A dedicated short range radar system is provided for use with a GPS system. The radar system includes a transmitter which transmits a microwave radio signal. A receiver is coupled to a horizontally scanning receiver antenna array which receives an echo, if present, from the radio signal transmitted by the transmitter. The radio receiver then generates an output signal representative of the echo. A control circuit then receives the output signal from the antenna array as well as the output signal from the GPS system. The control circuit then varies the mode of operation of the receiver and/or the transmitter as a function of the type of roadway for optimal radar performance.

Abstract: A homodyne radar system includes a mixer that outputs a signal having a mixer output frequency that is a frequency difference between two input signals. When the frequency difference is small, low frequency noise may mask the actual signal. A variable phase shifter is added to one of the mixer inputs to change the phase at a predetermined rate of change. The phase shifter shifts the frequency of the input signal so that the mixer output frequency is offset by the predetermined rate. The low frequencies are mapped to frequencies that are above the noise frequencies. The phase shift may be achieved by adding a constant phase at predetermined time intervals. The sampling frequency for the resulting signal may need to be increased to accommodate the higher frequencies.

Abstract: A system includes an antenna having a substrate and a plurality of antenna elements disposed on the substrate. A processing device is configured to measure an aperture function across an aperture of the antenna and determine whether at least one of the antenna elements is blocked based at least in part on the measured aperture function.

Abstract: An example radar apparatus has a transmission frequency modulated by a chirp waveform having three chirp segments, including increasing, decreasing, and a constant frequency segments. The chirp waveform may extend over the full revisit time of the radar beam. The frequency difference between the transmitted and echo signals are determined at least once per chirp segment. Example apparatus include a Doppler radar for vehicle use.

Abstract: A dedicated short range radar system is provided for use with a GPS system. The radar system includes a transmitter which transmits a microwave radio signal. A receiver is coupled to a horizontally scanning receiver antenna array which receives an echo, if present, from the radio signal transmitted by the transmitter. The radio receiver then generates an output signal representative of the echo. A control circuit then receives the output signal from the antenna array as well as the output signal from the GPS system. The control circuit then varies the mode of operation of the receiver and/or the transmitter as a function of the type of roadway for optimal radar performance.

Abstract: An example radar apparatus has a transmission frequency modulated by a chirp waveform having three chirp segments, including increasing, decreasing, and a constant frequency segments. The chirp waveform may extend over the full revisit time of the radar beam. The frequency difference between the transmitted and echo signals are determined at least once per chirp segment. Example apparatus include a Doppler radar for vehicle use.

Abstract: At least one electromagnetic lens having a first contour is disposed proximate to a dielectric substrate having a first edge having a second contour. A plurality of antenna feed elements, for example, end-fire antennas, are disposed on the dielectric substrate along the second contour. A signal applied to a corporate feed port is switched to the antenna feed elements by a switching network, wherein each antenna feed element launches an electromagnetic wave that is diffracted by the at least one electromagnetic lens so as to form an associated beam of electromagnetic energy. Different antenna feed elements generate different beams of electromagnetic energy in different directions. A pair of electromagnetic lenses with associated antenna feed elements at different edge locations on the dielectric substrate provide for bi-static operation. A reflector may be used to redirect the beams of electromagnetic energy.

Abstract: At least one electromagnetic lens having a first contour is disposed proximate to a dielectric substrate having a first edge having a second contour. A plurality of antenna feed elements, for example, end-fire antennas, are disposed on the dielectric substrate along the second contour. A signal applied to a corporate feed port is switched to the antenna feed elements by a switching network, wherein each antenna feed element launches an electromagnetic wave that is diffracted by the at least one electromagnetic lens so as to form an associated beam of electromagnetic energy. Different antenna feed elements generate different beams of electromagnetic energy in different directions. A pair of electromagnetic lenses with associated antenna feed elements at different edge locations on the dielectric substrate provide for bi-static operation. A reflector may be used to redirect the beams of electromagnetic energy.