Ford Aerospace & Communications Corporation

Ching C Han

Edgar W Matthews, Jr

Evert C Nygren

Paul D Frank

Yeongming Hwang

Jack E Kelly

David F Ford

Herman W Bilenko

This device provides for a substantially orthogonal transition or connection point between a strip transmission line configuration (one conductor, or two conductors sandwiched around a dielectric support, positioned in air between two ground planes such as might be used in a microwave antenna feed network) and a coaxial line section. The particular construction of the 'side-launch transition' suppresses spurious parallel plate modes, and, in the case of two conductors surrounding a dielectric, trapped modes which occur between the two conductors. A U-shaped upper 'dam' and corresponding lower 'dam,' electrically interconnected at several points, surround the termination of the stripline conductor(s) and provide suppression of parallel plate moding at the transition. In the case of two conductors surrounding a dielectric, electrical interconnection at the terminal point of the stripline conductors suppresses the trapped modes before they can be launched. The system has been found to provide extremely low voltage standing wave ratios over a wide range of microwave frequencies.

Orthogonal launcher for dielectrically supported air stripline

This specification discloses a microwave antenna system using an offset J-hook feed to achieve low sidelobe energy level over the entire radiation space from an electrical circular reflector antenna. An electromagnetic horn is positioned along the central axis of symmetry of a parabolic reflector. A waveguide feed is coupled to the horn and intersects the reflective surface at a position offset from the axis of symmetry.

Offset J-hook reflector antenna

The antenna system employs a parabolic reflector fed by an offset feed array of circular wave guides located substantially at the focus of the parabolic reflector, but offset from the axis thereof. A plurality of aperture tuning mechanisms disposed at the mouths of the circular waveguides of the waveguide feed array, and having physical lengths much shorter than one wavelength at the frequencies involved, are provided to reduce cross-polarization and mutual coupling between adjacent feeds. The short resonant length of these tuning mechanisms, and their shape which is chosen to generate the TM.sub.11 mode E-field contour line ensures that they are effective over a broad bandwidth of as much as 20% or more. Within this bandwidth, they act as inductive suppressors to control both cross-polarization and mutual coupling between adjacent feeds.

Microwave antenna system having enhanced band width and reduced

This device provides for a substantially orthogonal transition or connection point between a strip transmission line configuration (one conductor, or two conductors sandwiched around a dielectric support, positioned in air between two ground planes such as might be used in a microwave antenna feed network) and a coaxial line section. The particular construction of the 'side-launch transition' suppresses spurious parallel plate modes, and, in the case of two conductors surrounding a dielectric, trapped modes which occur between the two conductors. A U-shaped upper 'dam' and corresponding lower 'dam,' electrically interconnected at several points, surround the termination of the stripline conductor(s) and provide suppression of parallel plate molding at the transition. In the case of two conductors surrounding a dielectric, electrical interconnection at the terminal point of the stripline conductors suppresses the trapped modes before they can be launched. The system has been found to provide extremely low voltage standing wave ratios over a wide range of microwave frequencies.

Growing community of inventors

Los Altos, CA, United States of America

Ching C Han