Helix-loaded spiral antenna
US4012744A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 20, 1975 |
| Grant date | Mar 15, 1977 |
| Priority date | — |
| Expiry date | Oct 20, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q21/29
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A circularly polarized, broad-beamed antenna system capable of effectively covering the entire bandwidth of from about 0.5 GHz to about 18 GHz or higher. The system provided comprises a generally conventional planar spiral antenna modified by having the outer ends of its arms terminated by a bifilar helix. The bifilar helix is positioned behind the planar spiral and at 90.degree. to it. By proper coupling of the two antenna portions, it has been found that within the 2 to 18 GHz range, the planar spiral operates as if the helix were not present, while below 2 GHz, the spiral functions as a transmission line feeding the helix and the helix radiates essentially all of the energy from the antenna. The antenna system provided is approximately the same size as conventional 2 to 18 GHz cavity backed spiral antennas and generally satisfies all of the physical constraints and limitations placed upon airborne radar-warning systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.