Ground plane interference elimination by passive element
US4737796A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1986 |
| Grant date | Apr 12, 1988 |
| Priority date | — |
| Expiry date | Jul 30, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q1/528
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The radiation pattern of a beam at elevation angles near the horizon is improved for phased array antennas by control of the radiation field intensity near the horizon to reduce multipath disturbances, and to improve the axial ratio of a circularly polarized phased array antenna. This is accomplished by placing a parasitic phase shifting element directly below the antenna beam axis. The waveguide section is designed to produce a phase shift in the portion of antenna radiation energy passing through it to cancel some of the radiation energy in the direction of the horizon. The spacing of the waveguide section in front of the antenna is determined empirically for optimum results, i.e., for reduction of beam power below about 20.degree. without affecting beam power at high elevation angles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.