Methods and systems for shaping an electromagnetic wavefront are disclosed. A disclosed method includes tuning a tunable surface in an electromagnetic cavity and receiving the electromagnetic wavefront in the electromagnetic cavity. The electromagnetic wavefront includes a first wave defined by a first wavelength and a second wave defined by a second wavelength. The first wave and the second wave have a shared phase and a shared beam direction in the electromagnetic wavefront. The method further includes reflecting the electromagnetic wavefront within the cavity to repeatedly interact with the tunable surface, and transmitting, after reflecting the electromagnetic wavefront within the cavity, the electromagnetic wavefront from the electromagnetic cavity as a shaped electromagnetic wavefront. The first wave and the second wave have at least one of a difference in phase or a difference in beam direction in the shaped electromagnetic wavefront.

Methods and systems for shaping an electromagnetic wavefront are disclosed. A disclosed method includes tuning a tunable surface in an electromagnetic cavity and receiving the electromagnetic wavefront in the electromagnetic cavity. The electromagnetic wavefront includes a first wave defined by a first wavelength and a second wave defined by a second wavelength. The first wave and the second wave have a shared phase and a shared beam direction in the electromagnetic wavefront. The method further includes reflecting the electromagnetic wavefront within the cavity to repeatedly interact with the tunable surface, and transmitting, after reflecting the electromagnetic wavefront within the cavity, the electromagnetic wavefront from the electromagnetic cavity as a shaped electromagnetic wavefront. The first wave and the second wave have at least one of a difference in phase or a difference in beam direction in the shaped electromagnetic wavefront.

A waveguide slot antenna includes a waveguide having a plurality of slots spaced apart by a predefined distance in a central-axis direction of the waveguide, as a radiating section. An uneven section provided on an outer wall surface around the radiating section has a periodic concave-convex pattern extending from the radiating section. The uneven section includes a plurality of protrusions spaced apart by a predefined distance in a dispersed manner in each of an axis direction parallel to the central-axis of the waveguide in which the plurality of slots are arranged and an axis direction orthogonal to the central-axis of the waveguide, and grooves between the protrusions. The plurality of protrusions and the grooves causes incident waves incident from forward in a direction of radiation of radio waves emitted from the radiating section to be reflected in a direction different from an incident direction of the incident waves.

A two-port antenna system is proposed that uses a polarization-independent spatial power divider to align the beams from two orthogonally oriented dual-polarized feeds. This antenna system is compatible with fully polarimetric radar and provides high port isolation. It simultaneously provides a common aperture for transmit and receive to minimize radar parallax. The spatial power divider is designed using a combination of all-dielectric metamaterial techniques and the concept of miniaturized-element frequency selective surfaces, and is fabricated on a silicon wafer using standard microfabrication technology.

A two-port antenna system is proposed that uses a polarization-independent spatial power divider to align the beams from two orthogonally oriented dual-polarized feeds. This antenna system is compatible with fully polarimetric radar and provides high port isolation. It simultaneously provides a common aperture for transmit and receive to minimize radar parallax. The spatial power divider is designed using a combination of all-dielectric metamaterial techniques and the concept of miniaturized-element frequency selective surfaces, and is fabricated on a silicon wafer using standard microfabrication technology.

Provided is a dual-band multimode antenna feed for a high-frequency band and a low-frequency band. The feed includes four high-frequency waveguide ports, where each high-frequency waveguide port is connected to a respective high-frequency input/output waveguide. Each high-frequency input/output waveguide includes a high-frequency waveguide aperture facing a first section for mixing electromagnetic modes in the E-plane. The first section is connected to a second section for mixing electromagnetic modes in the H-plane. The feed further includes a low-frequency waveguide port connected to a low-frequency input/output waveguide. A filter is arranged inside the first section to be transparent for plane wave modes exhibited at lower frequencies and reflecting for plane wave modes exhibited at higher frequencies.

Provided is a dual-band multimode antenna feed for a high-frequency band and a low-frequency band. The feed includes four high-frequency waveguide ports, where each high-frequency waveguide port is connected to a respective high-frequency input/output waveguide. Each high-frequency input/output waveguide includes a high-frequency waveguide aperture facing a first section for mixing electromagnetic modes in the E-plane. The first section is connected to a second section for mixing electromagnetic modes in the H-plane. The feed further includes a low-frequency waveguide port connected to a low-frequency input/output waveguide. A filter is arranged inside the first section to be transparent for plane wave modes exhibited at lower frequencies and reflecting for plane wave modes exhibited at higher frequencies.

A multi-frequency folded lens antenna structure includes a stack, and the stack includes a polarization-dependent trans-reflector, a dielectric gap, and a multi-frequency twist-reflector; wherein the polarization-dependent trans-reflector is configured to transmit electromagnetic radiation of a first polarization incident from within the stack out of the stack and to reflect electromagnetic radiation of a second, different polarization incident within the stack towards the multi-frequency twist-reflector, and the multi-frequency twist-reflector is configured to selectively change a polarization of the reflected electromagnetic radiation from the second polarization to substantially the first polarization and to direct the electromagnetic radiation of substantially the first polarization, within the stack, towards the polarization-dependent trans-reflector for at least partial transmission out of the stack, wherein the multi-frequency twist-reflector is configured to selectively change the polarization for at least a first frequency band and for at least a second frequency band, non-contiguous to the first frequency band.

A multi-frequency folded lens antenna structure includes a stack, and the stack includes a polarization-dependent trans-reflector, a dielectric gap, and a multi-frequency twist-reflector; wherein the polarization-dependent trans-reflector is configured to transmit electromagnetic radiation of a first polarization incident from within the stack out of the stack and to reflect electromagnetic radiation of a second, different polarization incident within the stack towards the multi-frequency twist-reflector, and the multi-frequency twist-reflector is configured to selectively change a polarization of the reflected electromagnetic radiation from the second polarization to substantially the first polarization and to direct the electromagnetic radiation of substantially the first polarization, within the stack, towards the polarization-dependent trans-reflector for at least partial transmission out of the stack, wherein the multi-frequency twist-reflector is configured to selectively change the polarization for at least a first frequency band and for at least a second frequency band, non-contiguous to the first frequency band.

A dual polarized antenna feed system can include a first single polarized antenna feed element oriented on a first axis relative to a polarization filter and a second single polarized antenna feed element oriented on a second axis relative to the polarization filter such that the first and second axes are not common and not parallel. The polarization filter can include a plurality of conductors, a polarization of the first single polarized antenna feed element can be parallel to the plurality of conductors so that the polarization filter can reflect a majority of incident signals originating from the first single polarized antenna feed element, and a polarization of the second single polarized antenna feed element can be orthogonal to the plurality of conductors so that the polarization filter can be transparent to a majority of incident signals originating from the second single polarized antenna feed element.