A radio wave reflection reducing sheet provided with a laminate having a first primary surface and a second primary surface is disclosed. The laminate has: a first resin foam layer having a thickness from 0.05 to 3.00 mm and a density from 0.10 to 0.85 g/cm.sup.3, and a second resin foam layer having a thickness from 0.05 to 3.00 mm and a density from 0.20 to 0.90 g/cm.sup.3. The density of the second resin foam layer is greater than the density of the first resin foam layer. The first resin foam layer and the second resin foam layer are disposed in this order from the first primary surface side.

The present application relates to radio detection and ranging (radar) systems and, in particular, to a radar system having a photonics-based signal generator. Such a radar system comprises a stepped-frequency optical signal generator, an optical-to-electrical converter, and a transmitter. The stepped-frequency optical signal generator is configured for converting an optical signal into a stepped-frequency optical signal. The optical-to-electrical converter for converting the stepped-frequency optical signal into a stepped-frequency electrical signal. The transmitter for transmitting a microwave signal based on the stepped-frequency electrical signal.

The present application relates to radio detection and ranging (radar) systems and, in particular, to a radar system having a photonics-based signal generator. Such a radar system comprises a stepped-frequency optical signal generator, an optical-to-electrical converter, and a transmitter. The stepped-frequency optical signal generator is configured for converting an optical signal into a stepped-frequency optical signal. The optical-to-electrical converter for converting the stepped-frequency optical signal into a stepped-frequency electrical signal. The transmitter for transmitting a microwave signal based on the stepped-frequency electrical signal.

An antenna device (1) includes an antenna element (6) and a plurality of EBG elements (10), in which the plurality of EBG elements (10) includes a plurality of first EBG elements (11) and a plurality of second EBG elements (12) having a structure different from a structure of the plurality of first EGB elements (11).

A sensing system. In some embodiments, the system includes a first imaging radio frequency receiver, a second imaging radio frequency receiver, a first optical beam combiner, a first imaging optical receiver, a second optical beam combiner, and an optical detector array. The first optical beam combiner may be configured to combine optical signals of the imaging radio frequency receivers. The second optical beam combiner may be configured to combine the optical signals of the imaging radio frequency receivers, and the optical signal of the first imaging optical receiver.

The present disclosure relates to apparatuses and methods for a radar device. For example, an antenna device has a first set of antennas to establish first propagation channels and a second set of antennas to establish second propagation channels. A signal processing device determines a first differential phase shift among first radar signals propagating via the first propagation channels and a second differential phase shift among second radar signals propagating via the second propagation channels. Antennas of the first set are located at positions that generate the first differential phase shift for a first multitude of target angles, and antennas of the second set are located at positions that generate the second differential phase shift for a second multitude of target angles. The processing device determines an angular position of a target object as a unique target angle that is part of the first and second multitude of target angles.

A radar device includes: a first receiver antenna outputting a first reception signal; a second receiver antenna outputting a second reception signal; a third receiver antenna outputting a third reception signal; a first receiver circuit processing the first reception signal; and a second receiver circuit selecting one of the second reception signal and the third reception signal and processing the selected signal. The first receiver antenna is placed apart from the second receiver antenna in a first direction and apart from the third receiver antenna in a second direction.

A radar device includes: a first receiver antenna outputting a first reception signal; a second receiver antenna outputting a second reception signal; a third receiver antenna outputting a third reception signal; a first receiver circuit processing the first reception signal; and a second receiver circuit selecting one of the second reception signal and the third reception signal and processing the selected signal. The first receiver antenna is placed apart from the second receiver antenna in a first direction and apart from the third receiver antenna in a second direction.

A radar sensor having a frame, a housing arranged at the frame, a transmission and reception unit for high frequency signals arranged within the housing, wherein a radiation direction of the high frequency signals irradiated by the transmission and reception unit is rotatable about an axis of rotation. The radiation direction of the high frequency signals irradiated by the transmission and reception unit is substantially orthogonally oriented toward the axis of rotation, and the housing is supported at the frame rotatably about a pivot axis.

A radar sensor having a frame, a housing arranged at the frame, a transmission and reception unit for high frequency signals arranged within the housing, wherein a radiation direction of the high frequency signals irradiated by the transmission and reception unit is rotatable about an axis of rotation. The radiation direction of the high frequency signals irradiated by the transmission and reception unit is substantially orthogonally oriented toward the axis of rotation, and the housing is supported at the frame rotatably about a pivot axis.