Abstract: A synthetic aperture radar (SAR) system generates an image of a first swath. The SAR includes at least one SAR antenna, at least one SAR processor and at least one SAR transceiver. In operation the SAR defines a first beam to illuminate the first swath and one or more second beams to illuminate area(s) of ambiguity associated with the first beam. The SAR transmits a pulse via the first beam and receives backscatter energy. The SAR generates a first signal associated with the first beam and one or more second signals associated with the second beam(s). The second signal(s) are combined with determined complex vector(s), generating ambiguity signal(s) and the ambiguity signals are combined with the first signal to generate an image associated with the first swath.

Abstract: A synthetic aperture radar (SAR) system generates an image of a first swath. The SAR includes at least one SAR antenna, at least one SAR processor and at least one SAR transceiver. In operation the SAR defines a first beam to illuminate the first swath and one or more second beams to illuminate area(s) of ambiguity associated with the first beam. The SAR transmits a pulse via the first beam and receives backscatter energy. The SAR generates a first signal associated with the first beam and one or more second signals associated with the second beam(s). The second signal(s) are combined with determined complex vector(s), generating ambiguity signal(s) and the ambiguity signals are combined with the first signal to generate an image associated with the first swath.

Abstract: An electron beam pattern-writing column comprises an emitter and an extractor (14, 15) for generating a low-energy electron beam (13), a series of three electrostatic triple element lenses (17, 18, 21) for focussing the beam, and an electrostatic double deflector (20), which is disposed ahead of the final lens (21), for deflecting the beam to scan a substrate (11) on which a pattern is to be written. After focussing and deflection of the beam have been carried out by the electrostatic components, which are low power and thus have no significant heat output, the beam electrons are accelerated by the final element (21c) of the final lens (21) into a high-energy beam with the required strength for high-quality pattern writing.

Abstract: A magnetic lens system is provided for a beam of charged particles, comprising a pair of ring-shaped permanent magnets through which the beam passes, the axes of the rings lying coaxially along the beam direction, and the two rings being axially separated and axially oppositely magnetised. A pair of separated conducting focus coils are provided one for each ring, the axes of the focus coils lying coaxially along the beam direction, each focus coil lying within its associated ring, and the focus coils being connected in series opposition to carry an adjustable direct electric current for fine focusing of the beam by the lens without rotation of the focused beam. The lens may provide the fast fine focus adjustment needed to compensate for space charge defocussing produced by changes in beam current.

Abstract: The apparatus, which may be an electron beam column, has a lens system for coarse- and fine-focus adjustments of the beam. The coarse-focus is effected by a magnetic lens (10) and the fine-focus by an electric lens (14) in parallel with the magnetic lens. The electric lens may comprise a plurality of electrically conductive cylinders (14a to 14d) inside the magnetic lens. The cylinders are so arranged that, by applying appropriate potentials to them, fine-focus adjustments can be carried out without causing the beam to rotate.