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US 8,045,641 B2Granted
Encoding of RFID
AssigneeWavelogics AB
InventorDhanesh G Kurup
Life of this patent
Estimating the term…
Abstract
A method is disclosed for generating data encoded RF (radio frequency) waveform without a separate memory device/chip. The hardware in the proposed method consists of entities performing the operations of time-delay (B), phase shifting (C), attenuation, power dividing (D) and power combining (E). An integral part of the invention is the application of the method in designing radio frequency identification devices or RFID-tags.
Claims15
A method for generating a modulated waveform in a radio frequency identification (RFID) system tags, said method comprising:
- providing K signals SiM referred to as mother signals of duration TiM and frequencies Fi, where i=1 to K and K≧1;
- generating from said K mother signals K further signals of duration TiC referred to as child signals SiC, where TiC<TiM;
- dividing each of said child signal corresponding to each mother signal by means of a powder divider into Ni branches resulting in further Ni child signals where Ni≧2;
- introducing different delays TDji to said Ni further child signals after power division, wherein said delays being defined according to a predetermined modulation scheme to be either TDji=j×TiC, where j=1 . . . Ni, or TDji−TDj-1i=tx, where j=2 . . . Ni and tx=t0 for a binary zero and tx=t1 for a binary one with t0≠t1;
- and
- forming a signal string by combining said Ni signals, wherein said signal string will be interpreted as a data encoded signal corresponding to the mother signal i carrying an identification information.
3 more elements
A method for generating a modulated waveform comprising:
- providing K signals referred to as mother signals SIM of duration Ti and frequencies Fi, where i=1 to K and K≧1;
- dividing each of said K mother signals into Mi pairs of signals uk1, uk2 in Ni branches by means of an Ni-way power divider where Ni≧2, Ni=2Mi, 1≦k≦Mi;
- introducing different delays TDj to and phase shifts Φ°j to said Mi pairs of signals after power division, wherein said delays being defined according to a predetermined modulation scheme to either be TDj=j×Ti or TDj−Tj-1=tx, where tx=t0 for a binary zero and tx=t1 for a binary one with t0≠t1, wherein said phase shifts are defined such that the signals uk1, uk2 in each signal pair are 180° out of phase;
- and
- forming a signal string by combining said Mi pairs of signals, wherein said signal string will be interpreted as a data encoded signal carrying identification information.
2 more elements
A radio frequency identification, RFID, tag comprising:
- a signal provider configured to provide K signals referred to as mother signals SiM of duration TiM and frequency Fi, where i=1 . . . K and K≧1;
- a circuitry configured to generate from said K mother signals K further signals of duration TiC referred to as child signals SiC, where TiC<TiM, said circuitry comprising:
- a two-way power divider configured to split a mother signal SiM into two signals with equal power, said two-way power divider being connected to a first branch and a second branch;
- and
- a two-way power combiner connected to said first branch and said second branch and configured to combine said two signals into a child signal;
- said first branch comprising a first time delay;
- and said second branch comprising a second, different time delay and a phase shifter of angle Φ°, where Φ is adjusted such that a phase difference between said two signals at said power combiner is 180°;
- a power divider configured to divide each of said child signals corresponding to each mother signal into Ni branches resulting in Ni further child signals, where Ni≧2;
- a respective delay TDij arranged in said Ni further branches to introduce different delays to said Ni child signals after power division, wherein said delays being defined according to a predetermined modulation scheme to be either TDij=j×TiC, where j=1 . . . Ni, or TDij−TDj-1i=tx, where j=2 . . . Ni and tx=t0 for a binary zero and tx=t1 for a binary one with t0≠t1;
- and
- a power combiner configured to form a signal string by combining said Ni signals, wherein said signal string will be interpreted as a data encoded signal corresponding to mother signal i carrying identification information.
8 more elements
A radio frequency identification, RFID, tag comprising:
- a signal provider configured to provide K signals referred to as mother signals SiM of duration Ti and frequency Fi, where i=1 . . . K and K≧1;
- a power divider configured to divide each of said K mother signals into Mi pairs of signals uk1,uk2 in Ni branches, where Ni≧2 and Ni=2Mi, 1≦k≦Mi;
- each of said Ni branches comprises a respective time delay TDj and a respective phase shifter Φj, wherein each delay being defined according to a predetermined modulation scheme to either be TDj=j×Ti or TDj−TDj-1=tx, where tx=t0 for a binary zero and tx=t1 for a binary one with t0≠t1 and said phase shifters are defined such that the signals uk1,uk2 in each signal pair are 180° out of phase;
- and
- a power combiner connected to said Ni branches and configured to form a signal string by combining said Mi pairs of signals, where said signal string will be interpreted as a data encoded signal carrying identification information.
2 more elements
A method for generating a modulated waveform in a radio frequency identification, RFID, system, comprising:
- dividing a mother signal S1M of duration TM by a two-way power divider into two signals with equal power;
- delaying a first signal of said two signals with a first time delay;
- and
- delaying a second signal of said two signal with a second, different time delay;
- phase shifting said second signal with an angle Φ°, where Φ is adjusted such that a phase difference between said two signals is 180° when combining said signals;
- and
- forming a child signal S1C and a tail signal of duration TC by combining said signals, where TC<TM.
4 more elements
A device for generating a modulated waveform in a radio frequency identification, RFID, system, comprising:
- a two-way power divider configured to divide a mother signal S1M of duration TM into two signal with equal power;
- a first time delay configured to delay a first signal of said two signals;
- a second, different time delay configured to delay a second signal of said two signals;
- a phase shifter configured to phase shift said first signal with an angle Φ°, where Φ is adjusted such that a phase difference between said two signals is 180° when combining said signals;
- and
- a two-way power combiner configured to form a child signal S1C and a tail signal of duration TC, by combining said signals, where TC<TM.
3 more elements
Dependencies are inferred from the claim text.