# US 11,115,083 B2 · Direct conversion polar transmitter for an RFID reader > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,115,083 B2 - Document ID: US11115083B2 - Status: Granted - Kind: B2 - Application number: 16/744,898 - Filed: 2020-01-16 - Published: 2020-05-14 - Granted: 2021-09-07 - Earliest claimed: 2014-02-10 - Assignees: Clairvoyant Technology LLC - Applicants: Clairvoyant Technology, Inc. - Inventors: Thomas J. Frederick - Web page: https://patentgrep.com/patent/US11115083B2 ## CPC - G06K 7/10009: {sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves} - H04B 5/77: for interrogation - H04L 25/4902: {Pulse width modulation; Pulse position modulation} - H04L 27/04: Modulator circuits; Transmitter circuits - H04L 27/06: Demodulator circuits; Receiver circuits - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A polar transmitter for an RFID reader and a system using the polar transmitter are disclosed. An RFID system according to at least some embodiments of the invention includes a polar transmitter, a receiver to receive responses from RFID tags, and a coupler connected to the polar transmitter, the receiver and one or more antennas. In at least some embodiments, the polar transmitter of the RFID system includes an envelope amplifier and a power amplifier. In some examples, a polar transmitter includes direct conversion of baseband data to provide angle modulation plus drive modulation. In addition to the envelope amplifier and power amplifier, the polar transmitter in such an example includes a quadrature modulator connected to the power amplifier to provide modulation for the transmitter output signal using a Cartesian input signal. ## Claims ### Claim 1 A radio frequency identification (RFID) system comprising: a receiver to receive responses from RFID tags; and a polar transmitter, the polar transmitter further comprising: a power amplifier to produce a transmitter output signal; an envelope amplifier connected to the power amplifier to supply an envelope signal to the power amplifier; a quadrature modulator connected to the power amplifier to provide modulation for the transmitter output signal using a cartesian input signal; and a continuous wave source connected to the quadrature modulator. ### Claim 2 (depends on 1) The RFID system of claim 1 further comprising a coupler connected to the polar transmitter and the receiver to pass the transmitter output signal to one or more antennas and to pass the responses to the receiver. ### Claim 3 (depends on 1) The RFID system of claim 1 wherein the receiver and the polar transmitter are separable. ### Claim 4 (depends on 1) The RFID system of claim 1 wherein the envelope amplifier further comprises a multi-phase buck converter. ### Claim 5 (depends on 1) The RFID system of claim 1 further comprising: a driver amplifier connected to the power amplifier; and a DC blocking capacitor connected between the driver amplifier and the power amplifier. ### Claim 6 (depends on 1) The RFID system of claim 1 wherein the envelope amplifier further comprises: a switch mode power supply; and a linear regulator connected to the switch mode power supply. ### Claim 7 A method of operating a transmitter for a radio frequency identification (RFID) system, the method comprising: producing, using a processor, a cartesian in-phase signal and a cartesian quadrature-phase signal; supplying the cartesian in-phase signal and the cartesian quadrature-phase signal to a quadrature modulator; supplying a continuous wave signal to the quadrature modulator; supplying an envelope signal from an envelope amplifier to a power amplifier; and driving the power amplifier using the quadrature modulator to produce a transmitter output signal. ### Claim 8 (depends on 7) The method of claim 7 further wherein driving the power amplifier further comprises: using the quadrature modulator to drive a driver amplifier; and using the driver amplifier to drive the power amplifier. ### Claim 9 (depends on 7) The method of claim 7 wherein the transmitter output signal is produced using offset phase reversal amplitude shift keying (OPR-ASK). ### Claim 10 Apparatus for radio frequency identification (RFID) comprising: means for producing a cartesian in-phase signal and a cartesian quadrature-phase signal; means for supplying an envelope signal to a power amplifier; means for supplying a continuous wave signal for use in modulating the power amplifier; and means for modulating the power amplifier using the cartesian in-phase signal and the cartesian quadrature-phase signal to produce a transmitter output signal. ### Claim 11 A radio frequency (RF) system comprising: a power amplifier to produce a transmitter output signal; an envelope amplifier connected to the power amplifier to supply an envelope signal to the power amplifier; a quadrature modulator connected to the power amplifier to provide modulation for the transmitter output signal using a cartesian input signal; and a continuous wave source connected to the quadrature modulator. ### Claim 12 (depends on 11) The RF system of claim 11 wherein the envelope amplifier further comprises a multi-phase buck converter. ### Claim 13 (depends on 11) The RF system of claim 11 further comprising a driver amplifier connected to the power amplifier. ### Claim 14 (depends on 13) The RF system of claim 13 further comprising a DC blocking capacitor connected between the driver amplifier and the power amplifier. ### Claim 15 (depends on 11) The RF system of claim 11 wherein the envelope amplifier further comprises a switch mode power supply. ### Claim 16 (depends on 15) The RF system of claim 15 wherein the envelope amplifier further comprises a linear regulator connected to the switch mode power supply.