Abstract:
An electronically controlled monolithic array antenna includes a transmission line through which an electromagnetic signal may be propagated, and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element. The antenna element includes a conductive ground plate; an array of conductive edge elements defining the coupling edge, each of the edge elements being electrically connected to a control signal source, and each of the edge elements being electrically isolated from the ground plate by an insulative isolation gap; and a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate across the insulative isolation gap so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.
Abstract:
An apparatus and methods for operating a frequency selective surface are disclosed. The apparatus can be tuned to an on/off state or transmit/reflect electromagnetic energy in any frequency. The methods disclosed teach how to tune the frequency selective surface to an on/off state or transmit/reflect electromagnetic energy in any frequency.
Abstract:
A lens (300, 500) is disclosed for steering the exit direction (Ω) of an incident electromagnetic wave. The lens comprises a main body (210, 510) of a ferroelectric material with a first main surface (207, 507) and a first transformer (220, 222). The electromagnetic wave enters and exits the lens through the transformer, and the lens comprises means (370, 380) for creating a DC-field in a first direction in the main body. The main body (210, 510) of ferroelectric material comprises a plurality (21011-210NN, 51011-510NN) of slabs of the ferroelectric material, each slab also comprising a first (403, 603) and a second electrode of a conducting material. The means for creating a DC-field can create a gradient DC-field in the first direction using the first and second electrodes, so that the dielectric constant in the main body will also be a gradient in the first direction, thus enabling steering of the existing electromagnetic wave.
Abstract:
Es wird eine Radarantennenanordnung, insbesondere für Kraftfahrzeuge vorgestellt bestehend aus einem länglichen Wellenleiter, in welchen elektromagnetische Wellen derart eingekoppelt werden, dass sich diese in Längsrichtung (X) des Wellenleiters ausbreiten, und einer Störstruktur (12) mit einer Mehrzahl von metallischen Abschnitten, wobei die Störstruktur in der Nähe des Wellenleiters, beabstandet vom Wellenleiter in eine erste Querrichtung (Y) zum Wellenleiter, zumindest näherungsweise parallel zur Längsrichtung (X) des Wellenleiters angeordnet ist, so dass die Störstruktur eine gerichtete Abstrahlung von Radarwellen bewirkt. Erfindungsgemäß weist der Wellenleiter in Längsrichtung zwei metallische Flächen (31 ,41 ) und zwischen diesen ein dielektrisches Medium (32,42) auf, wobei die Flächen (31 ,41 ) in einer zweiten Querrichtung (Z) verlaufen, die sowohl senkrecht zur ersten Querrichtung (Y) als auch zur Längsrichtung (X) des Wellenleiters steht. Vorzugsweise ist die Störstruktur (12) als eine drehbare Trommel mit auf dem Umfang veränderten metallischen Abschnitten ausgestaltet und ein Reflektoranordnung zur Bündelung und Polarisation der Wellen vorgesehen.
Abstract:
A beam switching antenna system and method and apparatus for controlling the same is provided, by which optimal antenna characteristics can be maintained according to a peripheral environment, the necessary time and power consumption of searching an optimal beam-direction can be reduced, and electromagnetic waves of a beam generated from an antenna can be minimized. The beam switching antenna system includes an antenna element (1) for transmitting and receiving a beam; a dielectric body (7) surrounding said antenna element; at least one conductive reflector (3, 6) facing a lateral outside of said dielectric body; and a ground switch circuit connected to said at least one conductive reflector. The ground switch circuit includes a reference voltage source generating a reference voltage; a ground line (4) connected to the reference voltage source; an electrical switching device (5) connected between the ground line (4) and the conductive reflector (3, 6); and a controller for controlling the electrical switching device. The conductive reflector includes an upper conductive reflector (3) having one end connected to one terminal of the electrical switching device; and a lower conductive reflector (6) having one end connected to another terminal of the electrical switching device and the other end connected to the ground line (4).
Abstract:
An antenna and antenna excitation method. The inventive antenna includes a cylindrical array (20) of radiating elements. Each of the elements is mounted at a predetermined substantially transverse angle relative to a longitudinal axis. A circuit (30) is included for providing an electrical potential between at least two of the elements effective to scan a transmit or a receive beam of electromagnetic energy along an elevational axis at least substantially transverse to the longitudinal axis. In the illustrative embodiment, the array includes a stack of the planar, parallel, conductive, ring-shaped radiating elements, each of which is filled with ferroelectric bulk material. A second circuit (70) is included for exciting at least some of the elements to cause the elements to generate a transmit or a receive beam of electromagnetic energy off-axis relative to the longitudinal axis. In the preferred embodiment, the second circuit is a Butler matrix and is effective to cause the beam to scan in azimuth about the longitudinal axis, the azimuthal axis being at least substantially transverse to the longitudinal axis and the elevational axis.
Abstract:
A substrate (2) has a surface on which is provided a modifying layer which is incomplete and has a distribution such as to provide a plurality of islands of said material and/or islands of substrate surface whereby the surface exhibits a modified electrical and/or magnetic property. As shown, substrate (2) is piezoelectric, and has a central electrode (9) and a peripheral electrode (10), between which are deposited a large number of electrically conductive dots having a dot density which decreases with distance from electrode (9). The construction acts as a sonar transducer over a relatively wide frequency range.