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 unit includes a coupler, a phase-shifting modulator, and an antenna element. The coupler has first and second input-output ports, a coupled port, and an isolated port. The phase-shifting modulator includes a transmission medium coupled to the coupled port, a reflector, control nodes, and active devices each having a respective first device port coupled to a respective location of the transmission medium, a respective second device port coupled to the reflector, and a respective control port coupled to a respective one of the control nodes. And the antenna element is coupled to the phase-shifting modulator via the isolated port.

Abstract: An embodiment an antenna unit of an antenna array includes a signal coupler, a phase-shifting modulator, and an antenna element. The signal coupler has a first input-output port, a second input-output port, and a coupled port. The phase-shifting modulator is coupled to the coupled port of the signal coupler, and the antenna element is coupled to the phase-shifting modulator via a connection remote from the signal coupler, or via an isolated port of the signal coupler. The phase-shifting modulator is configured for both relatively low signal loss and relatively low power consumption such that the antenna array can have significantly lower C-SWAP metrics than a conventional phased array while retaining the higher performance metrics of a conventional phased array.

Abstract: Antennas such as flat panel, leaky wave antennas with directional coupler feeds and waveguides are disclosed. In one example, an antenna includes a surface having antenna elements, a guided wave transmission line, and a coupling surface. The guided wave transmission line provides a guided feed wave. The coupling surface is between and separates the guided wave transmission line and the surface having antenna elements. The coupling surface controls coupling of the guided feed wave to the antenna elements. The coupling surface can also spatially filter the guided feed wave to provide a more uniform power density for the antenna elements. The guided feed wave can be a high power density electromagnetic wave or a density radially decaying electromagnetic wave.

Abstract: Antennas such as flat panel, leaky wave antennas with directional coupler feeds and waveguides are disclosed. In one example, an antenna includes a surface having antenna elements, a guided wave transmission line, and a coupling surface. The guided wave transmission line provides a guided feed wave. The coupling surface is between and separates the guided wave transmission line and the surface having antenna elements. The coupling surface controls coupling of the guided feed wave to the antenna elements. The coupling surface can also spatially filter the guided feed wave to provide a more uniform power density for the antenna elements. The guided feed wave can be a high power density electromagnetic wave or a density radially decaying electromagnetic wave.

Abstract: An embodiment an antenna unit of an antenna array includes a signal coupler, a phase-shifting modulator, and an antenna element. The signal coupler has a first input-output port, a second input-output port, and a coupled port. The phase-shifting modulator is coupled to the coupled port of the signal coupler, and the antenna element is coupled to the phase-shifting modulator via a connection remote from the signal coupler, or via an isolated port of the signal coupler. The phase-shifting modulator is configured for both relatively low signal loss and relatively low power consumption such that the antenna array can have significantly lower C-SWAP metrics than a conventional phased array while retaining the higher performance metrics of a conventional phased array.

Abstract: An antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a radial waveguide; an aperture operable to radiate radio frequency (RF) signals in response to an RF feed wave fed by the radial waveguide; and a radio frequency (RF) choke operable to block RF energy from exiting through a gap between outer portions of the waveguide and the aperture.

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: Antennas such as flat panel, leaky wave antennas with directional coupler feeds and waveguides are disclosed. In one example, an antenna includes a surface having antenna elements, a guided wave transmission line, and a coupling surface. The guided wave transmission line provides a guided feed wave. The coupling surface is between and separates the guided wave transmission line and the surface having antenna elements. The coupling surface controls coupling of the guided feed wave to the antenna elements. The coupling surface can also spatially filter the guided feed wave to provide a more uniform power density for the antenna elements. The guided feed wave can be a high power density electromagnetic wave or a density radially decaying electromagnetic wave.

Abstract: An antenna having radio-frequency (RF) resonators and methods for fabricating the same are described. In one embodiment, the antenna comprises a physical antenna aperture having an array of antenna elements, where the array of antenna elements includes a plurality of radio-frequency (RF) resonators, with each RF resonator of the plurality of RF resonators having an RF radiating element with a microelectromchanical systems (MEMS) device.

Abstract: An apparatus with a rectangular waveguide to radial mode transition and method for using the same are described. In one embodiment, the apparatus comprises a radial waveguide having at least one plate; a radio-frequency (RF) launch coupled to the radial waveguide comprising a rectangular waveguide, a rectangular waveguide to coaxial transition coupled to the rectangular waveguide, and a coaxial to radial transition coupled to the rectangular waveguide to coaxial transition.

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: Antennas such as flat panel, leaky wave antennas with directional coupler feeds and waveguides are disclosed. In one example, an antenna includes a surface having antenna elements, a guided wave transmission line, and a coupling surface. The guided wave transmission line provides a guided feed wave. The coupling surface is between and separates the guided wave transmission line and the surface having antenna elements. The coupling surface controls coupling of the guided feed wave to the antenna elements. The coupling surface can also spatially filter the guided feed wave to provide a more uniform power density for the antenna elements. The guided feed wave can be a high power density electromagnetic wave or a density radially decaying electromagnetic wave.

Abstract: An antenna having radio-frequency (RF) resonators with tunable capacitors. In one embodiment, the tunable capacitor for tuning an RF resonator comprises: a first substrate with a first electrode attached thereto; a second substrate with a second electrode attached thereto; and a membrane between the first and second electrodes, the membrane being movable between the first and second electrodes in order to change capacitance.

Abstract: An antenna having radio-frequency (RF) resonators and methods for fabricating the same are described. In one embodiment, the antenna comprises a physical antenna aperture having an array of antenna elements, where the array of antenna elements includes a plurality of radio-frequency (RF) resonators, with each RF resonator of the plurality of RF resonators having an RF radiating element with a microelectromchanical systems (MEMS) device.

Abstract: An antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a radial waveguide; an aperture operable to radiate radio frequency (RF) signals in response to an RF feed wave fed by the radial waveguide; and a radio frequency (RF) choke operable to block RF energy from exiting through a gap between outer portions of the waveguide and the aperture.