Abstract: Double reflector electromagnetic systems implementable in miniaturized satellites and other applications for compact, light weight, and broadband antennas. The disclosed methods and devices include primary and secondary reflectors, where the secondary reflector is held in the aperture plane of the primary reflector to minimize required space. A specific Cassegrain configuration is also described.

Abstract: Double reflector electromagnetic systems implementable in miniaturized satellites and other applications for compact, light weight, and broadband antennas. The disclosed methods and devices include primary and secondary reflectors, where the secondary reflector is held in the aperture plane of the primary reflector to minimize required space. A specific Cassegrain configuration is also described.

Abstract: A contraband detection system especially suited for detecting concealed non-metallic contraband such as ceramic or plastic weapons or illegal drugs carried by a person is disclosed. Plural sources of quasi-coherent millimeter wave radiation are disposed so as to uniformly illuminate a field of view. In the preferred embodiment, the radiation emitted by the sources is linearly polarized in a single plane such that the polarization of the radiation with respect to the plane in which linearly polarized radiation is preferentially received by the detectors can be controlled. For detection of dielectric objects, such as ceramic weapons or narcotics, these planes of polarization should be orthogonal to one another. The detector is a staring array which does not require scanning to generate an image of the entire field of view; the signal provided by each element of the detector array corresponds to the illumination reflected from objects in a single portion of the field of view.

Abstract: A millimeter wave imaging system is disclosed which has wide applicability throughout transportation and related industries. For example, the system may be used to provide an aircraft pilot with an image of a landing field which is essentially unaffected by fog, rain, snow, blowing sand, etc. The system comprises an array of imaging elements as its fundamental component. Each of the imaging elements of the basic array comprises an antenna consisting of a pair of conductive elements and a non-linear circuit element connected thereacross. A image can then be formed responsive to millimeter-wave radiation without complex processing steps or any form of mechanical or electronic scanning.To increase the sensitivity of the imaging array system, a local oscillator signal may be mixed with the energy received from the field of view in each of the imaging elements by the non-linear circuit element. The oscillator used to provide the local oscillator signal can also be used to illuminate the field of view.

Abstract: A contraband detection system especially suited for detecting concealed non-metallic contraband such as ceramic or plastic weapons or illegal drugs carried by a person is disclosed. Plural sources of quasi-coherent millimeter wave radiation are disposed so as to uniformly illuminate a field of view. In the preferred embodiment, the radiation emitted by the sources is linearly polarized in a single plane such that the polarization of the radiation with respect to the plane in which linearly polarized radiation is preferentially received by the detectors can be controlled. For detection of dielectric objects, such as ceramic weapons or narcotics, these planes of polarization should be orthogonal to one another. The detector is a staring array which does not require scanning to generate an image of the entire field of view; the signal provided by each element of the detector array corresponds to the illumination reflected from objects in a single portion of the field of view.

Abstract: A millimeter wave sensing device is disclosed comprising a local oscillator source generating a millimeter wave signal which is mixed with millimeter wave radiation reflected from or emitted by objects in a field of view. The mixing is performed in a staring array of mixer/detector elements which need not be mechanically or electronically scanned to generate signals responsive to the entire field of view. In a first embodiment of the invention, the device detects millimeter wave radiation emitted by or reflected from the object to be imaged. In a second embodiment of the invention, the oscillator used to provide the local oscillator signal is also used to illuminate the field of view. In the second embodiment of the invention, the oscillator signal is preferably linearly polarized, and a polarizing grid is used to separate the local oscillator signal and illumination beam and direct them in a simple and efficient manner.

Abstract: A millimeter wave object detection and location system is disclosed comprising a source generating a millimeter wave signal which is divided into an illumination beam, directed onto a field of view, and a local oscillator portion, mixed with radiation reflected from objects in the field of view. The mixing is performed in a staring array of mixer/detector elements which need not be mechanically or electronically scanned to generate signals responsive to the entire field of view. The detected signal from each element is directly responsive to a portion of the field of view. The oscillator signal is preferably linearly polarized, and a polarizing grid is used to separate the local oscillator signal and illumination beam and direct them in a simple and efficient manner. A twist reflector may also be used to rotate the polarization of a portion of the beam to direct it onto the mixer/detector array for mixing with the received signal from the field of view.