Active antenna for two-way transmission
US5280633A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1991 |
| Grant date | Jan 18, 1994 |
| Priority date | — |
| Expiry date | Mar 14, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/601
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
This active antenna is incorporated in the terminal station of a system for data exchange with a central station, by the modulation of a microwave carrier. The terminal station is of the chip card type. The modem of the active antenna is constituted by a transistor, the bias current of which is switched over from a low value at demodulation to a high value at modulation. The switch-over is obtained by a circuit with three resistors (R.sub.d, R.sub.gd, R.sub.g), which themselves have their values switched over by two transistors parallel connected with the resistors, these transistors being controlled by two signals emitted by the control circuit of the terminal station. The active antenna can be applied to long-distance data exchange, for example in the remote management of toll-charge systems, remote cash dispensing, localization of moving bodies etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.