Telefonaktiebolaget Lm Ericsson (publ)

Saab Ericsson Space Ab

Saab Encsson Space Ab

Ulf Jostell

Ingmar Karlsson

Magnus Bonnedal

Jean Marc Barraco

Mikael Ohgren

Anders Carlstrom

A quadrifilar helix antenna () comprising a first and a second set of helical antenna elements () symmetrically arranged around a longitudinal axis extending through the axial center of the antenna (). The antenna () is excited from feeding points () in a local ground plane at the bottom () of the antenna. The helical antenna elements () of the first set are interconnected in respective top ends of the elements at the top () of the antenna. The bottom ends of the first set are in galvanic contact with the respective feeding points (). The antenna is characterized in that the top ends of helical antenna elements () of the second set are arranged in an open circuit and remain unconnected. The bottom ends of the helical antenna elements () of the second set each includes a connection () to the local ground plane.

Quadrifilar helix antenna

An inexpensive high gain antenna for use on terminals communicating with low earth orbit (LEO) satellites which include an elevation table mounted for arcuate movement about a transverse axis on an azimuth turntable mounted for rotational movement about a central axis. A plurality of antenna elements forming a phased array antenna are mounted on the top of the elevation table and have a scan plane which is parallel to and extends through the transverse axis of the elevation table. The antenna may be both mechanically and electrically scanned and is used to perform handoffs from one LEO satellite to another by positioning the elevation table of the antenna with its boresight in a direction intermediate the two satellites and with the scan plane of the antenna passing through both satellites. At the moment of of handoff, the antenna beam is electronically scanned from one satellite to another without any loss in data communication during the process.

Terminal antenna for communications systems

Antenna element for two orthogonal polarizations

Growing community of inventors

Molndal, Sweden

Ulf Jostell