# US 11,442,142 B2 · Interference-canceling RF receiver circuit, corresponding system, radar sensor system, vehicle and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,142 B2 - Document ID: US11442142B2 - Status: Granted - Kind: B2 - Application number: 16/795,977 - Filed: 2020-02-20 - Published: 2020-09-03 - Granted: 2022-09-13 - Earliest claimed: 2019-02-28 - Assignees: STMicroelectronics S.r.l. - Applicants: STMicroelectronics S.r.l. - Inventors: Giuseppe Papotto; Egidio Ragonese; Claudio Nocera; Alessandro Finocchiaro; Giuseppe Palmisano - Web page: https://patentgrep.com/patent/US11442142B2 ## CPC - G01S 7/023: {Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques (auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36)} - G01S 7/038: {Feedthrough nulling circuits} - G01S 7/352: {Receivers} - G01S 13/931: of land vehicles - H03D 7/1466: {Passive mixer arrangements} - H03F 1/56: Modifications of input or output impedances, not otherwise provided for - H03F 3/19: with semiconductor devices only - H04B 1/123: {using adaptive balancing or compensation means (adaptive filter circuits and algorithms H03H)} - H04B 1/525: with means for reducing leakage of transmitter signal into the receiver - H03F 2200/451: the amplifier being a radio frequency amplifier - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H03D: DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER (masers, lasers H01S; circuits capable of acting both as modulator and demodulator H03C; details applicable to both modulators and frequency-changers H03C; demodulating pulses H03K9/00; transforming types of pulse modulation H03K11/00; coding, decoding or code conversion, in general H03M; repeater stations H04B7/14; demodulators adapted for AC systems of digital information transmission H04L27/00; synchronous demodulators adapted for colour television H04N9/66) - H03F: AMPLIFIERS - H04B: TRANSMISSION ## Abstract An input receives a radio frequency (RF) signal having an interfering component superimposed thereon. The RF signal is mixed with a local oscillator (LO) signal and down-converted to an intermediate frequency (IF) to generate a mixed signal which includes a frequency down-converted interfering component. The mixed signal is amplified by an amplifier to generate an output signal. A feedback loop processes the output signal to generate a correction signal for cancelling the frequency down-converted interfering component at the input of the amplifier. The feedback loop includes a low-pass filter and a amplification circuit which outputs the correction signal. ## Claims ### Claim 1 A radio frequency (RF) receiver circuit, comprising: an RF input port; an input network configured to receive an RF signal from said RF input port and to provide an RF current signal, said RF signal having an interfering component superimposed thereon; a mixer circuit, comprising a signal input, a local oscillator (LO) input and an intermediate frequency (IF) output and configured to: a) receive said RF current signal at said signal input; b) receive a LO signal at said LO input; and c) provide a mixed signal at said IF output; wherein the mixed signal comprises a frequency down-converted interfering component; an interference-canceling loop configured to provide at an output a corrected IF signal, wherein the interference-canceling loop comprises: an amplifier circuit having an input coupled to said IF output of the mixer circuit and an output; and a feedback network configured to generate a compensation current for application to the mixed signal at the input of said amplifier circuit as a function of the signal at the output of said amplifier circuit, thereby removing said frequency down-converted interfering component in said mixed signal. ### Claim 2 (depends on 1) The RF receiver circuit of claim 1, wherein the feedback network comprises a trans-conductance amplifier circuit and a low-pass filter stage, the trans-conductance amplifier having input nodes coupled to said output through said low-pass filter stage. ### Claim 3 (depends on 2) The RF receiver circuit of claim 2, wherein the amplifier circuit comprises a trans-impedance amplifier having: input nodes coupled to the mixer IF output; and output nodes coupled to said input nodes of the feedback network. ### Claim 4 (depends on 1) The RF receiver circuit of claim 1, wherein: the input network comprises an impedance matched voltage-to-current converter network; and the mixer circuit comprises a passive mixer. ### Claim 5 (depends on 4) The RF receiver circuit of claim 4, wherein the passive mixer comprises a switch quad type mixer of a passive Gilbert-cell type. ### Claim 6 (depends on 1) The RF receiver circuit of claim 1, further comprising: at least one antenna coupled to the RF input port; and a local oscillator configured to generate the LO signal. ### Claim 7 (depends on 1) The RF receiver circuit of claim 1, wherein the RF receiver circuit is a component of a vehicular radar sensor system. ### Claim 8 (depends on 7) The RF receiver circuit of claim 7, wherein vehicular radar sensor system is a component of a vehicle. ### Claim 9 A method, comprising: receiving a radio frequency (RF) signal having an interfering component superimposed thereon, wherein receiving the RF signal comprises receiving the RF signal as a voltage signal and converting said voltage signal to a current signal; receiving a local oscillator (LO) signal generated by an oscillator; signal mixing said RF signal and said LO signal to generate a mixed signal comprising a frequency down-converted intermediate frequency (IF) interfering component; amplifying said mixed signal in a feedback loop; applying an interference-canceling feedback signal generated by said feedback loop to the mixed signal before amplifying, thereby removing said IF interfering component in said mixed signal; and outputting a corrected IF signal to user stages. ### Claim 10 (depends on 9) The method of claim 9, wherein receiving the RF signal comprises applying impedance matching. ### Claim 11 A circuit, comprising: a mixing circuit having a signal input configured to receive a radio frequency (RF) signal which includes a superimposed interfering component, a local oscillator (LO) input configured to receive a LO signal and a signal output generating a downconverted signal at an intermediate frequency (IF) which includes an IF interfering component; a trans-impedance amplifier having an input configured to receive the downconverted signal with the IF interfering component and an output configured to generate an amplified IF output signal; a filter circuit having an input configured to receive the amplified IF output signal; and a trans-conductance amplifier circuit having an input configured to receive a filtered signal output from the filter circuit and an output configured to apply a cancellation signal to the downconverted signal at the input of the trans-impedance amplifier which cancels the IF interfering component present within the downconverted signal. ### Claim 12 (depends on 11) The circuit of claim 11, wherein the low-pass filter is configured to pass frequencies which include a frequency of the IF interfering component. ### Claim 13 (depends on 11) The circuit of claim 11, wherein the mixing circuit comprises a switch quad type mixer of a passive Gilbert-cell type.