A tag detection system comprising a source for producing an interrogation signal having a first frequency; a harmonic radar tag comprising: an antenna structure; a tunneling junction electrically and integrally coupled to the antenna; and wherein the harmonic radar tag when stimulated by the interrogation signal having the first frequency, and the harmonic radar tag produces a response signal at a second frequency different from the first frequency.

A device for measuring and/or monitoring tire-related variables of a vehicle, having a sensor unit for transmitting, receiving and processing signals, wherein a transmission signal is emitted by an antenna unit of the sensor unit in the direction of an object being measured and wherein a reflection signal reflected by the object being measured is received and analysed, the sensor unit having a transceiver device, via by means of which a reflection factor, formed as the quotient from the reflection signal reflected by the object being measured and the transmission signal, is measured and via which a resonance frequency and/or a phase difference between the transmission signal and the reflection signal is determined, wherein the transceiver unit comprises a vector network analyser and an analysis unit, so that a distance to the object being measured is established by detecting the phase difference between the transmission signal and the reflection signal.

For passive sensor with resonator having a natural frequency, a method comprises: a first phase emission of an electromagnetic signal toward the passive sensor at an emission frequency, the resonator oscillating in a forced regime at the emission frequency and then oscillating at its natural frequency when the emission is cut off; a first phase reception of the damped signal oscillating at natural frequency emitted by passive sensor, a measurement of the frequency being performed; a second phase emission of an electromagnetic signal at the measured frequency toward the passive sensor, the resonator oscillating in a forced regime at the measured frequency and then oscillating at its natural frequency when the emission is cut off; a second phase reception of the damped signal oscillating at natural frequency, a measurement of the frequency being performed, determination of the natural frequency being stopped due to measurement performed in this second reception phase.

A method for locating devices that transmit, backscatter or receive a wireless signal. The method comprising using each of one or more backscatter devices to modulate and backscatter a carrier signal transmitted by a transmitter. Modulating and backscattering the carrier signal generates a backscattered modulated signal comprising a sideband. The method further comprises receiving the one or more backscattered modulated signals with a receiver. At least one of the phase or amplitude of each sideband are used to determine at least one of: the distance between the transmitter and the backscatter device by which that sideband was generated, the distance between the receiver and the backscatter device by which that sideband was generated, and the sum thereof.

Metamaterials are employed with satellites, e.g., small satellites, to increase the observability of such satellites. Any type of suitable metamaterial can be used. In exemplary embodiments fractal-based patterns or structures may be used. A super scatterer having a metasurface is employed for the satellite and enhances the radar reflection for a given area of the satellite. Such detection can be used for monitoring and/or controlling the orbits of satellite space craft.

A code reading method and a radar system using a short-range millimeter wave (mmWave) radar are provided. The method includes transmitting a mmWave radar signal to a target object from a radar system and receiving a reflection wave signal reflected on the target object, extracting reflection signal strengths for a plurality of line codes constituting the target object from the reflection wave signal, compensating for the reflection signal strengths considering a difference in antenna gain between the plurality of line codes as per an antenna radiation pattern of the radar system, forming a radar image using the compensated reflection signal strengths, and reading a binary code from the radar image.

A method for locating devices that transmit, backscatter or receive a wireless signal. The method comprising using each of one or more backscatter devices to modulate and backscatter a carrier signal transmitted by a transmitter. Modulating and backscattering the carrier signal generates a backscattered modulated signal comprising a sideband. The method further comprises receiving the one or more backscattered modulated signals with a receiver. At least one of the phase or amplitude of each sideband are used to determine at least one of: the distance between the transmitter and the backscatter device by which that sideband was generated, the distance between the receiver and the backscatter device by which that sideband was generated, and the sum thereof.

Inferring product activity includes providing a first product having an attached first harmonic tag; directing, at a first area in which the first product is located, a first transmitted signal of a first frequency; and receiving a first return signal of a first return frequency from the first harmonic tag, wherein the first harmonic tag, upon receiving the first transmitted signal, radiates the first return signal, such that the first return frequency is a harmonic of the first frequency. A computer can then infer, based on the first return signal, a first activity in which the first product is being used.

A harmonic radar apparatus includes a transmitter configured to transmit a plurality of fundamental frequencies towards a scene. A further aspect of the harmonic radar apparatus includes a receiver configured to receive a reflected signal from the scene, the reflected signal being modulated based on the scene, and a re-radiated signal from a tag, the re-radiated signal being at a harmonic frequency of at least one of the plurality of fundamental frequencies transmitted by the transmitter.

The invention relates to a reflector comprising a reflector cavity (110) having a front opening for receiving EMR into the reflector cavity (110) for subsequent reflection of the EMR by at least one reflector element (120) arranged within the reflector cavity (110), characterized in that the reflector further comprises a front cover (130) that has high EM R transmittance in at least parts of the EM spectrum, the front cover (130) being arranged to cover the front opening of the reflector cavity (110), and that the front cover (130) and front opening form a gastight seal (140) impermeable to gas to prevent transport of material into and out of the reflector cavity (110) through the front opening.