Abstract: The invention relates to an imaging system having a reflect array for reflection of radiation such as millimeter-wave radiation. It can apply to imaging systems which operate over a wide range of wavelengths.

Abstract: An imaging system comprises a transmitter (24, 25), a receiver (24, 25, 21), and a controller (20) for directing the transmitter and the receiver to scan an object in a volume. The controller determines which sub-volumes of the volume the object is located within and then performs a fine scan in those sub-volumes. This reduces overall scanning time. The controller (20) may compare a received signal sample magnitude from the initial scan with a threshold to make the decision. The initial scan may be performed with a spot size to include only one or more particular volume elements within at least some of the sub-volumes.

Abstract: An imaging system (1) comprises an antenna array (2), 24 GHz transceivers (3), and a digital receiver (4) including an ADC and circuits for filtering. The digital receives commands from the host PC (5) and passes data to the host PC (5) for display. The host PC 5 initiates volume scans, performs system diagnostics and error reporting, and collects scan data and displays it for the operator. The digital receiver (4) presents the scan requests to the antenna array (2) in a synchronised manner. All control signals in the antenna array are presented via a presentation clock (an individual presentation clock being generated for sub-sections of the array; of the order of five hundred presentation clocks are generated). The spectral content of each presentation clock is adjusted via a spreading circuit, thus adjusting the spectral interference radiated through the printed circuit board traces to the FET elements that each presentation clock feeds. The spreading clock generation circuit include taps (Tap 1, Tap 2 . .

Abstract: Electrical properties of concealed dielectric objects, such as the dielectric permittivity, can be deduced from incident, reflected, and transmitted electromagnetic waves in an imaging system. In a confocal arrangement a horn illuminates a reflect array and the reflect array is configured to focus the radiation at an element in the scan volume. The reflections are in turn refocused by a reflect array at the horn aperture. The reflect array is electronically configured to scan the focal point throughout the scan volume in a systematic way. Knowledge of the horn pattern and the scan strategy allows the system to compute the geometry associated with each volume element. Amplitude and phase variations between the object and the surrounding volume and the computed geometry are used to estimate the relative permittivity and thus facilitate categorization of the object using a database of material relative permittivities.

Abstract: An imaging system comprises a transmitter (24, 25), a receiver (24, 25, 21), and a controller (20) for directing the transmitter and the receiver to scan an object in a volume. The controller determines which sub-volumes of the volume the object is located within and then performs a fine scan in those sub-volumes. This reduces overall scanning time. The controller (20) may compare a received signal sample magnitude from the initial scan with a threshold to make the decision. The initial scan may be performed with a spot size to include only one or more particular volume elements within at least some of the sub-volumes.

Abstract: Electrical properties of concealed dielectric objects, such as the dielectric permittivity, can be deduced from incident, reflected, and transmitted electromagnetic waves in an imaging system. In a confocal arrangement a horn illuminates a reflect array and the reflect array is configured to focus the radiation at an element in the scan volume. The reflections are in turn refocused by a reflect array at the horn aperture. The reflect array is electronically configured to scan the focal point throughout the scan volume in a systematic way. Knowledge of the horn pattern and the scan strategy allows the system to compute the geometry associated with each volume element. Amplitude and phase variations between the object and the surrounding volume and the computed geometry are used to estimate the relative permittivity and thus facilitate categorization of the object using a database of material relative permittivities.

Abstract: An upconverter receives an intermediate frequency (IF) modulated signal on a port (5) and a local oscillator carrier signal at a port (6). A comb generator (13-15) generates a comb-like waveform from the carrier signal, the waveform having a peak for each of a number of multiples of the carrier fundamental. A bandpass filter (16) selects one of the comb peaks and there is further multiplication at a quadrupler (20). The modulated signal (IF) and the multiplied carrier are mixed in a mixer (23) to provide a high frequency upper sideband (LO+IF) output. The output is transmitted in a waveguide (7) which is integral with the casing (2, 3) and which performs high frequency filtering by virtue of its shape.

Abstract: An upconverter receives an intermediate frequency (IF) modulated signal on a port (5) and a local oscillator carrier signal at a port (6). A comb generator (13-15) generates a comb-like waveform from the carrier signal, the waveform having a peak for each of a number of multiples of the carrier fundamental. A bandpass filter (16) selects one of the comb peaks and there is further multiplication at a quadrupler (20). The modulated signal (IF) and the multiplied carrier are mixed in a mixer (23) to provide a high frequency upper sideband (LO+IF) output. The output is transmitted in a waveguide (7) which is integral with the casing (2, 3) and which performs high frequency filtering by virtue of its shape.