The invention provides a polarized RFID (
radio frequency identification)
system without chips. The polarized RFID
system without chips comprises a double channel
signal source, a horizontal polarization
branch circuit, a vertical polarization
branch circuit, a dual polarization antenna, and a
signal processing and
control circuit, wherein the double channel
signal source can generate two channels of radiofrequency signals with the same frequency and controllable phase at will; the horizontal polarization
branch circuit adjusts the amplitude of the first channel of
radiofrequency signal during the signal emission process, and performs
frequency mixing for a reflected signal and a
local oscillator signal during the process of receiving the reflected signal, and performs filtering and amplification when the
frequency conversion is taken down; the vertical polarization branch circuit adjusts the amplitude of the second channel of
radiofrequency signal during the signal emission process, and performs
frequency mixing for a reflected signal and a
local oscillator signal during the process of receiving the reflected signal, and performs filtering and amplification when the
frequency conversion is taken down; the dual polarization antenna emits two channels of radiofrequency signals with adjustable amplitude and phase, and can stimulate a pair of
linear polarization electromagnetic
waves which are vertical in the polarized direction; the two channels of
linear polarization electromagnetic
waves can be overlaid with any polarized electromagnetic
waves, and can receive the reflected signal; and the
signal processing and
control circuit is used for adjusting the
phase difference between two channels of radiofrequency signals, and is used for coding the reflected signal.