RADIO SYSTEM FOR DATA TRANSMISSION WITH PASSIVE TERMINAL STATION

摘要

The radio system embodying the invention comprises a central station and a passive terminal station. First and second data signals are transmitted between data processing units respectively connected to the central and terminal stations. The terminal station comprises a same low-cost circuit associated with a square two-dimensional antenna for detecting the amplitude of a first incident microwave emitted by the central station thereby recovering the first data signal and deriving, in response to the first microwaves, a microwave modulated in phase by the second data signal by means of a retroreflection of a second incident microwave. This second incident microwave is emitted by the central station to the two-dimensional antenna of the terminal station. The terminal station is of very simple design, is compact and can therefore be included as well as the corresponding data processing unit in a contact-free chip card.