US Government As Represented by the Secretary of the Army

James W Mink

Felix Schwering

J Robert Christian

A slab dielectric waveguide for the millimeter and sub-millimeter wave regions is achieved by providing a thin grounded dielectric slab of rectangular cross-section into which a sequence of equally spaced cylindrical lenses are fabricated. The axis of these lenses coincides with the center line of the slab guide, i.e. the propagation direction of the guide. The spacing of the lenses S is assumed to be on the order of many guide wavelengths .lambda.; the width of the slabguide w is on the order of at least several .lambda.; and the thickness d of the guide typically is sufficiently small so that only the fundamental surface wave mode can exist on the slab. If the permittivity of the lenses exceeds that of the guide, the lenses will have a convex shape and in the opposite case, the lenses will have a concave shape. As those skilled in the art will appreciate, the concave shape will simplify the fabrication of guide and will reduce its diffraction losses.

Hybrid dielectric slab beam waveguide

A plurality of millimeter wave power sources are arranged in a planar mat array located in a wave-beam resonator including two reflecting surfaces which are large in terms of the operating wavelength. One surface comprises a planar reflector located in relatively close proximity to the source array, while the other reflector is located in front of the array at a relatively larger distance and being partially transparent and curved, with the curvature being expressed by a pair of focal lengths which define a curvature in two perpendicular axial planes. Each source is comprised of an IMPATT or GUNN diode coupled to a short dipole or closed current loop structure, all lying in a plane parallel to the planar reflector and transverse to the longitudinal central axis of the resonator.

Solid state millimeter wave power combiner

To reduce guidance errors in a microwave landing system from false signals eflected by objects along runways, the transmitting antenna radiates an elliptically polarized beam. At the airborne receiver an antenna, such as a pyramidal horn, maintains the separation of the horizontal and vertical components. These components are separated and then split on an equal power basis. One part of the vertical field component is shifted by 90 degrees and added to one part of the horizontal component in a detector, whose output is in effect like that of a circularly polarized receiver. The other parts of the horizontal and vertical components are separately detected. The outputs of the three detectors are combined in a multiplier, to yield a resultant output. For a very broad angular distribution the undesired reflected signals are strongly attenuated.

Multipath discriminating antenna system

A rotary bucket wheel is positioned beneath and communicates with a water lumn of collected rain. When the water column exceeds a certain height, as determined by an electronic probe circuit, the bucket wheel is actuated whereby a predetermined volume of water is removed from the bottom of the water column.

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Raleigh, NC, United States of America

James W Mink