Vehicle roof mounted slot antenna with separate AM and FM feeds
US4721963A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1986 |
| Grant date | Jan 26, 1988 |
| Priority date | — |
| Expiry date | Jul 25, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q1/3275
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Slot antenna apparatus for a motor vehicle roof having a central portion made of electrically non-conducting material comprises a horizontal sheet of electrically conducting material attached to the roof with a looped slot adjacent the central portion of the roof dividing the sheet into inner and outer portions and having a total loop length of substantially one wavelength in the commercial FM broadcasting band. Antenna feed means are provided at the front center of the slot for FM receiver apparatus and at the side center of the slot essentially 90 degrees rotated from the front center of the slot for AM receiver apparatus. The AM and FM feeds may be connected by coaxial cable to AM and FM tuners in a common radio receiver in the vehicle dashboard; or separate AM and FM portions of the receiver may be installed adjacent the appropriate antenna feeds. The antenna is grounded at DC and in both the AM and FM commercial frequency bands. The horizontal sheet may comprise a conducting material having a sheet resistance of 1-2 ohms per square for a maximum VSWR of 5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.