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 a radar subsystem includes at least one antenna and a control circuit. The at least one antenna is configured to radiate at least one first transmit beam and to form at least one first receive beam. And the control circuit is configured to steer the at least one first transmit beam and the at least one first receive beam over a first field of regard during a first time period, and to steer the at least one first transmit beam and the at least one first receive beam over a second field of regard during a second time period.

Abstract: An embodiment of a radar subsystem includes at least one antenna and a control circuit. The at least one antenna is configured to radiate at least one first transmit beam and to form at least one first receive beam. And the control circuit is configured to steer the at least one first transmit beam and the at least one first receive beam over a first field of regard during a first time period, and to steer the at least one first transmit beam and the at least one first receive beam over a second field of regard during a second time period.

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 a radar subsystem includes at least one antenna and a control circuit. The at least one antenna is configured to radiate at least one first transmit beam and to form at least one first receive beam. And the control circuit is configured to steer the at least one first transmit beam and the at least one first receive beam over a first field of regard during a first time period, and to steer the at least one first transmit beam and the at least one first receive beam over a second field of regard during a second time period.

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.