Antenna switching apparatus
US5574987A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 20, 1994 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Dec 20, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The antenna switch of the present invention switches from a portable radio's internal antenna to an external, vehicle adapter antenna. The second antenna is part of the vehicle adapter that supplies DC power to the vehicle adapter. A 1/4-wavelength transformer couples the internal antenna to the portable radio's transceiver. Diodes couple transformer and antenna to ground. A 1/2-wavelength transformer couples the vehicle adapter to the transceiver. When the portable radio is connected to the vehicle adapter, DC power is supplied to the diodes causing them to appear as a short thus making the first transformer appear as an open circuit. This causes a signal from the transceiver to be conducted to the second antenna on the vehicle adapter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.