Techniques for adjusting operation of an electronic device
摘要
說明書
In some implementations, electronic tags 206 are capable of “l(fā)istening” on a first communication channel (e.g., an RFID channel), but not sending messages. In some implementations, electronic tags 206 are passive radar devices. Passive radar devices comprise radar devices that do not have a dedicated transmitter.
Passive radar devices include corner reflector devices and printed radar devices. Corner reflector devices are generally used to generate a strong radar echo from objects that would otherwise have only very low effective radar cross section (RCS). A corner reflector includes two or more electrically conductive surfaces that are mounted crosswise (e.g., at an angle of exactly 90 degrees). Incoming electromagnetic waves are backscattered by multiple reflection accurately in that direction from which they come. Thus, even small objects with small RCS yield a strong echo.
In some implementations, printed radar reflectors comprise simple aluminum fibers that form half-wave resonators within the object to be tracked (e.g., a piece of paper). The radar-reflecting fibers are approximately the same diameter as paper fibers (typically 6.5 mm long and 1.5 μm in diameter). Randomly oriented radar-reflecting fibers provide a unique backscatter pattern that can be read and stored in a database for future identification. Ordered patterns can also be designed so that individual resonators are coupled or decoupled, whatever is likely to give the optimum backscatter pattern. When illuminated with radar, the backscattered fields interact to create a unique interference pattern that enables one tagged object to be identified and differentiated from other tagged objects.
