Abstract: A radar or other microwave antenna comprises at least one antenna element, a feed structure for the element extending to the antenna element substantially normally thereto through a dielectric substrate, and characterized in that the dielectric substrate is anisotropic whereby to reduce unwanted common-mode currents in the feed structure. The anisotropy may be provided by elongate conductive elements distributed through the dielectric substrate and aligned with their longitudinal axes parallel to the feed structure.

Abstract: A planar Vivaldi antenna array, and method of forming such an array, the array comprising: a plurality of slots at an end of the antenna array, the slots extending through the whole thickness of the planar structure of the antenna array; and a plurality of grooves extending from the slots; wherein: the grooves do not extend through the whole thickness of the planar structure of the antenna array; and the cross-sectional shape of the grooves is complementary to the cross-sectional shape of the slots.

Abstract: An apparatus and method are provided for applying a fixed non-linear profile of power (amplitude) and delay to signals across the aperture of an array antenna having multiple antenna elements where multiple beams are formed to span the field of view of the antenna. Using such fixed profiles in combination enables a substantially constant beam width to be maintained across a wide range of operational frequencies, e.g. 6-18 GHz, ensuring that the points of overlap for adjacent beams does not drop below a certain level, e.g. ?3dB, and hence maintaining a substantially uniform coverage across the field of view of the antenna at all frequencies in the range.

Abstract: A planar Vivaldi antenna array, and method of forming such an array, the array comprising: a plurality of slots at an end of the antenna array, the slots extending through the whole thickness of the planar structure of the antenna array; and a plurality of grooves extending from the slots; wherein: the grooves do not extend through the whole thickness of the planar structure of the antenna array; and the cross-sectional shape of the grooves is complementary to the cross-sectional shape of the slots.

Abstract: A radar or other microwave antenna comprises at least one antenna element, a feed structure for the element extending to the antenna element substantially normally thereto through a dielectric substrate, and characterised in that the dielectric substrate is anisotropic whereby to reduce unwanted common-mode currents in the feed structure. The anisotropy may be provided by elongate conductive elements distributed through the dielectric substrate and aligned with their longitudinal axes parallel to the feed structure.

Abstract: An apparatus and method are provided for applying a fixed non-linear profile of power (amplitude) and delay to signals across the aperture of an array antenna having multiple antenna elements where multiple beams are formed to span the field of view of the antenna. Using such fixed profiles in combination enables a substantially constant beam width to be maintained across a wide range of operational frequencies, e.g. 6-18 GHz, ensuring that the points of overlap for adjacent beams does not drop below a certain level, e.g. ?3dB, and hence maintaining a substantially uniform coverage across the field of view of the antenna at all frequencies in the range.