Patent ID: 7249711

Claim:
A remotely readable sensor apparatus, comprising: a sensor system having a minimum detectable sensor-apparatus antenna capture area, comprising: at least one sensing circuit for converting environmental input data to digital data; a data processor for receiving said digital data and appending additional information thereto to form encoded data; a memory means for storing said encoded data as a data frame; a modulation signal generator for receiving said data frame stored in said memory means, forming a data packet therefrom and outputting a modulation sequence; an RF bi-phase modulator for receiving said modulation sequence; and a sensor-apparatus antenna having a detectable capture area and a reflection coefficient that is determined by the states of said RF bi-phase modulator; whereby said RF bi-phase modulator is driven by said modulation sequence to change said reflection coefficient angle by a P-N junction device, and to produce a reflected signal in response to a carrier signal; and a reader system, comprising: a reader transmitter for generating said carrier signal; a reader transmitting antenna for transmitting said carrier signal to said sensor-apparatus and reader receiving antenna for receiving said reflected signal from said sensor-apparatus; a reader receiver for processing said reflected signal to form a processed reflected signal; a demodulator for receiving said processed reflected signal and outputting said encoded data; an information decoder for decoding said encoded data to retrieve said data frame; and a local memory for storing said data frame.