General Signal Corporation

Spx Corporation

Richard I Bibber

Cole Nason Plummer

Brett J Grandchamp

Charles D Brown

John L Schadler

Andre Skalina

Jeffrey M Brown

James T Stenberg

Henry Downs

A dual-port IBOC&#xae; antenna provides omnidirectional radiation of orthogonal, circularly polarized analog (FM) and digital (OFDM) signals using quadruple coplanar square loops driven from a hybrid having balanced outputs. The loops are arranged in a tiled square, with proximal sides functioning as further stripline hybrids to cancel cross coupling between the loops. Each loop quad is reflector-backed and emits a directional signal; multiple loop quads oriented radially form an omni bay. Vertical spacing between bays includes a minimum position for mutual coupling, while symmetry establishes uniform input impedance on the hybrid input ports. Tuning barbs on the loops fine tune frequency response. Bandwidth is wide, so that a single antenna can radiate multiple FM analog and hybrid IBOC&#xae; channels over the VHF FM radio broadcast band.

Antenna system and method to transmit cross-polarized signals from a common radiator with low mutual coupling

A center-pivoted, conductive vane equipped with contact-enhancing finger stock on the wiping edges rests during normal operation of a modified waveguide section parallel to and equidistant between the broad faces of the waveguide, where it interacts minimally with RF propagating through the waveguide. When it is desired to provide a short circuit to the waveguide, for a safety lockout or other uses, the vane can be rotated into a position to provide a substantial barrier to RF propagation. Rotating the pivot shaft, to which the vane is rigidly attached, performs rotation of the vane. The shaft is equipped with lockable stops for the open and shorted positions. Multiple center-pivoted vanes in a multiple-branch waveguide can form a switch.

Apparatus and method for shorting waveguide using a pivotable vane structure

The rigid coaxial transmission line disclosed herein is made up of multiple sections having outer conductors which are joined together at flanges and make up a desired length. Rather than being of equal length, the sections vary in length progressively to prevent the reflections caused by the flanges from accumulating at any frequency within the band at which the transmission line is to operate.

Broadband rigid coaxial transmission line

The coaxial connector disclosed herein accommodates differential expansion between inner and outer conductors in a multi-section run of coaxial transmission line by utilizing a coupler assembly which connects adjacent inner conductors, one of the inner conductors being fixedly connected to the coupler with axial movement being permitted with respect to the other inner conductor. Electrical connection between the coupler and the movable conductor is established at a single axial position by an annular conductive spring member while longitudinal alignment is maintained over the rest of the length of the coupler by insulating rings set into annular grooves. A tubular shield extends from the coupler over the adjacent end of the movable inner conductor without electrical contact. The axial length of the shield is larger than the differential expansion which occurs between inner and outer conductor sections. The shield masks the gap at end of the movable inner conductor which is otherwise variable with differential expansion and thereby minimizes the changes in impedance at the connector.

Coaxial connector accommodating differential expansion

A directional coupler for coupling r.f. energy in a waveguide system from a main channel waveguide to a subsidiary channel waveguide, the coupling being in the range between about -3 dB to -15 dB. The coupler comprises a single coupling slot at the junction between the main channel waveguide and the subsidiary channel waveguide with an arrangement for decoupling the slot to yield the desired coupling, the arrangement including first and second posts in the plane of the junction. A further provision involves inductively loading the junction, the loading being provided at the plane of the junction. The provision for inductively loading the junction is an 'inverted' button, in the form of capped-off holes, the depth of the holes being adjusted to vary the directivity of the coupler.

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Gray, ME, United States of America

Richard I Bibber