Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of electronically steerable receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength, has an aperture, and is configured to generate a receive beam pattern. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength, has an aperture that is significantly smaller than the aperture of the sparse receive antenna, and is configured to filter, spatially, the receive beam pattern.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of electronically steerable receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength, has an aperture, and is configured to generate a receive beam pattern. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength, has an aperture that is significantly smaller than the aperture of the sparse receive antenna, and is configured to filter, spatially, the receive beam pattern.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of electronically steerable receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Abstract: An embodiment of an antenna includes first and second transmission lines, first antenna elements, and second antenna elements. The first transmission line is configured to guide a first signal such that the first signal has a characteristic of a first value, and the second transmission line is configured to guide a second signal such that the second signal has the same characteristic but of a second value that is different than the first value. The first antenna elements are each disposed adjacent to the first transmission line and are each configured to radiate the first signal in response to a respective first control signal, and the second antenna elements are each disposed adjacent to the second transmission line and are each configured to radiate the second signal in response to a respective second control signal. Such an antenna can have better main-beam and side-lobe characteristics, and a better SIR, than prior antennas.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of electronically steerable receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Abstract: An embodiment of an antenna comprises an array of antenna elements arranged in groups of antenna elements adjustably coupled to respective reference waves. A multiplicity of patterns of antenna coupling settings are defined, each of which gives rise to a main lobe which points the antenna in a particular direction, each pattern also giving rise to respective side lobes. First and second such patterns may point the antenna in the same direction but with non-identical side lobes. In this way the clutter level from the side lobes relative to the main lobe is much smaller than would be the case if one of the patterns were employed both for transmitting and receiving. Alternatively, the first and second patterns may be used in quick succession both for transmitting, or used in quick succession both for receiving. The antenna may also switch rapidly between patterns where the main lobe points in a different direction in each pattern, allowing dithering of the beam or rapid switching between scanning and tracking.

Abstract: An embodiment of an antenna includes first and second transmission lines, first antenna elements, and second antenna elements. The first transmission line is configured to guide a first signal such that the first signal has a characteristic of a first value, and the second transmission line is configured to guide a second signal such that the second signal has the same characteristic but of a second value that is different than the first value. The first antenna elements are each disposed adjacent to the first transmission line and are each configured to radiate the first signal in response to a respective first control signal, and the second antenna elements are each disposed adjacent to the second transmission line and are each configured to radiate the second signal in response to a respective second control signal. Such an antenna can have better main-beam and side-lobe characteristics, and a better SIR, than prior antennas.

Abstract: An embodiment of an antenna includes first and second transmission lines, first antenna elements, and second antenna elements. The first transmission line is configured to guide a first signal such that the first signal has a characteristic of a first value, and the second transmission line is configured to guide a second signal such that the second signal has the same characteristic but of a second value that is different than the first value. The first antenna elements are each disposed adjacent to the first transmission line and are each configured to radiate the first signal in response to a respective first control signal, and the second antenna elements are each disposed adjacent to the second transmission line and are each configured to radiate the second signal in response to a respective second control signal. Such an antenna can have better main-beam and side-lobe characteristics, and a better SIR, than prior antennas.

Abstract: In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Abstract: An embodiment of an antenna includes first and second transmission lines, first antenna elements, and second antenna elements. The first transmission line is configured to guide a first signal such that the first signal has a characteristic of a first value, and the second transmission line is configured to guide a second signal such that the second signal has the same characteristic but of a second value that is different than the first value. The first antenna elements are each disposed adjacent to the first transmission line and are each configured to radiate the first signal in response to a respective first control signal, and the second antenna elements are each disposed adjacent to the second transmission line and are each configured to radiate the second signal in response to a respective second control signal. Such an antenna can have better main-beam and side-lobe characteristics, and a better SIR, than prior antennas.

Abstract: An embodiment of an antenna comprises an array of antenna elements arranged in groups of antenna elements adjustably coupled to respective reference waves. A multiplicity of patterns of antenna coupling settings are defined, each of which gives rise to a main lobe which points the antenna in a particular direction, each pattern also giving rise to respective side lobes. First and second such patterns may point the antenna in the same direction but with non-identical side lobes. In this way the clutter level from the side lobes relative to the main lobe is much smaller than would be the case if one of the patterns were employed both for transmitting and receiving. Alternatively, the first and second patterns may be used in quick succession both for transmitting, or used in quick succession both for receiving. The antenna may also switch rapidly between patterns where the main lobe points in a different direction in each pattern, allowing dithering of the beam or rapid switching between scanning and tracking.

Abstract: A microwave paint thickness sensor includes a single cylindrical cavity, a microwave source, and a signal detector. The cylindrical cavity is open at one end, the open end having a choke joint for interfacing with a painted surface. The cylindrical cavity is designed so that the electronic field is normal to the painted surface. In a preferred embodiment, this is accomplished by providing an optimally designed TM011 mode cavity. In this configuration, the resonant frequency of the cavity is linearly related to the inverse of the paint thickness. In accordance with one aspect of the present invention, the resonant cavity is optimally sized to resonate at a frequency where the sensor footprint can be minimized. Thus with the use of the choke joint, the small sensor interface area of the present invention may easily be applied to a curved surface.

Abstract: A microwave paint thickness sensor includes a single cylindrical cavity, a microwave source, and a signal detector. The cylindrical cavity is open at one end, the open end having a choke joint for interfacing with a painted surface. The cylindrical cavity is designed so that the electronic field is normal to the painted surface. In a preferred embodiment, this is accomplished by providing an optimally designed TM011 mode cavity. In this configuration, the resonant frequency of the cavity is linearly related to the inverse of the paint thickness. In accordance with one aspect of the present invention, the resonant cavity is optimally sized to resonate at a frequency where the sensor footprint can be minimized. Thus with the use of the choke joint, the small sensor interface area of the present invention may easily be applied to a curved surface.