Radar apparatus and leakage correction method

• US 11,307,287 B2
• Filed: 10/24/2019
• Issued: 04/19/2022
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: RichWave Technology Corp
• Original Assignee: RichWave Technology Corp
• Inventors: Yeh, Chiang-Hua, Chi, Hsiang-Feng
• Primary Examiner(s): Moore, Whitney
• Application Number:
  US16/663,328
• Publication Number:
  US 20200132804A1
• Time in Patent Office: 908 Days
• Field of Search: None
• CPC Class Codes: G01S 13/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 7/038 Feedthrough nulling circuits
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G01S 7/358 using I/Q processing
• CPC Class Codes: G01S 7/4021 of receivers

Abstract

A radar apparatus and a leakage correction method thereof are provided. The radar apparatus includes a transmitter and a receiver. The transmitter includes a sinewave signal generator. The sinewave signal generator generates a sinewave signal. The receiver includes another sinewave signal generator and a correcting circuit. The receiver receives transmitting signals including the sinewave signal from the transmitter. The sinewave signal generator of the receiver generates another sinewave signal according to the amplitude of the transmitting signals or received transmitting signals. The correcting circuit corrects leakage situation on the received transmitting signals according to another sinewave signal. The phasor of sinewave form corresponding to the leakage situation relates to the phasor of another sinewave signal. Accordingly, the performance of receiver may be improved effectively.

Claims

1. A radar apparatus, comprising:

a transmitter, comprising;

a first sinewave signal generator, configured to generate a first sinewave signal; and

a first mixer, coupled to the first sinewave signal generator and configured to mix the first sinewave signal; and

a receiver, configured to receive a transmitting signal transmitted by the transmitter, wherein the transmitting signal comprises the first sinewave signal, and the receiver comprises;

a second mixer, configured to generate an intermediate frequency signal according to a received transmitting signal;

a second sinewave signal generator, configured to generate a second sinewave signal according to the intermediate frequency signal and according to an amplitude of the transmitting signal or an amplitude of the received transmitting signal; and

a correcting circuit, coupled to the second sinewave signal generator and the second mixer, and configured to correct a leakage situation of the received transmitting signal based on the second sinewave signal, wherein a phasor corresponding to the leakage situation n a sinewave form is related to a phasor of the second sinewave signal.

2. The radar apparatus according to claim 1, wherein the second sinewave signal generator adjusts an amplitude of the second sinewave signal based on an amplitude of the first sinewave signal to be not greater than an amplitude corresponding to the leakage situation.

3. The radar apparatus according to claim 1, wherein the second sinewave signal generator adjusts a phase of the second sinewave signal according to a phase corresponding to the leakage situation.

4. The radar apparatus according to claim 3, wherein the second sinewave signal generator adjusts the phase of the second sinewave signal to be the same as the phase corresponding to the leakage situation.

5. The radar apparatus according to claim 4, wherein the second sinewave signal generator changes the phase of the second sinewave signal, an amplitude corresponding to the leakage situation is based on a signal strength of the received transmitting signal, the correcting circuit corrects the received transmitting signal through the second sinewave signal with different phases, and the second sinewave signal generator determines the phase corresponding to the leakage situation as a phase corresponding to an amplitude, which is less than a threshold value, after the leakage situation has been corrected by the correcting circuit.

6. The radar apparatus according to claim 3, wherein the receiver comprises:

a control circuit, coupled to the second sinewave signal generator, and configured to determine in-phase/quadrate-phase information of the received transmitting signal, to determine an amplitude and the phase corresponding to the leakage situation.

7. The radar apparatus according to claim 1, comprising:

an oscillator, coupled to the first sinewave signal generator and the second sinewave signal generator, and configured to provide a clock signal to the first sinewave signal generator and the second sinewave signal generator, wherein

the first sinewave signal generator generates the first sinewave signal according to the clock signal, and the second sinewave signal generator generates the second sinewave signal according to the clock signal.

8. The radar apparatus according to claim 1, wherein one of the first sinewave signal generator and the second sinewave signal generator comprises:

a phasor generator, configured to generate a digital signal;

a digital-to-analog converter, coupled to the phasor generator, and configured to convert the digital signal into an analog signal; and

a filter, coupled to the digital-to-analog converter, and configured to filter the analog signal to generate one of the first sinewave signal and the second sinewave signal.

9. The radar apparatus according to claim 8, wherein the phasor generator comprises an over-sampling modulator.

10. The radar apparatus according to claim 8, comprising:

a radio frequency front-end circuit, configured to receive the transmitting signal to generate the received transmitting signal,

wherein the second mixer is coupled to the radio frequency front-end circuit and

an intermediate frequency amplifying circuit, coupled to the second mixer and the correcting circuit, and configured to receive the intermediate frequency signal, wherein the correcting circuit subtracts the second sinewave signal from the intermediate frequency signal processed by the intermediate frequency amplifying circuit.

11. The radar apparatus according to claim 8, wherein the received transmitting signal is a radio frequency signal, and the receiver further comprises:

a third mixer, coupled to the filter, and configured to generate a second radio frequency signal according to the second sinewave signal and a carrier signal, and the radar apparatus further comprises;

a radio frequency front-end circuit, coupled to the correcting circuit, and configured to receive the transmitting signal to generate the radio frequency signal, wherein the correcting circuit subtracts the second radio frequency signal from the radio frequency signal.

12. The radar apparatus according to claim 1, wherein

the second mixer is configured to mix the received transmitting signal to generate the intermediate frequency signal, and

the receiver further comprises:

at least one DC offset circuit, generating a first signal based on the intermediate frequency signal;

a filter, filtering out an AC portion related to the first signal and generating a second signal according to a DC portion related to the first signal; and

a controller, controlling the at least one DC offset circuit based on the second signal to reduce a DC portion of the intermediate frequency signal.

13. The radar apparatus according to claim 12, wherein the receiver further comprises:

an analog-to-digital converter, configured to receive a signal related to the first signal and convert the signal related to the first signal into a digital signal; and

a digital signal processor, configured to receive the digital signal and configured to generate a first correction value based on the digital signal,

wherein the controller generates a first control signal based on the second signal or the first correction value to control the at least one DC offset circuit.

14. The radar apparatus according to claim 12, wherein the receiver further comprises:

at least one amplifier, coupled between the at least one DC offset circuit and the filter, and the at least one amplifier amplifying the first signal to output an amplified first signal;

an analog-to-digital converter, configured to receive the amplified first signal and convert the amplified first signal into a digital signal; and

a digital signal processor, configured to receive the digital signal and generate a first correction value based on the digital signal,

wherein the controller generates a first control signal based on the second signal or the first correction value to control the at least one DC offset circuit.

15. The radar apparatus according to claim 12, wherein the controller comprises:

a first control circuit, generating a first control signal based on the second signal, wherein the at least one DC offset circuit reduces the DC portion of the intermediate frequency signal based on the first control signal; and

a second control circuit, generating a second control signal based on the second signal, wherein the at least one DC offset circuit further reduces the DC portion of the first signal based on the second control signal;

wherein the first control circuit is configured to perform a coarse adjustment operation on the at least one DC offset circuit, and the second control circuit is configured to perform a fine adjustment operation on the at least one DC offset circuit.

16. The radar apparatus according to claim 12, wherein the at least one DC offset circuit comprises:

a first controllable current source, comprising a first terminal coupled to a first reference voltage terminal;

a second controllable current source, comprising a second terminal coupled to a second reference voltage terminal; and

a resistor, comprising a first terminal and a second terminal respectively coupled to a second terminal of the first controllable current source and a first terminal of the second controllable current source, and one of the first terminal and the second terminal of the resistor is further coupled to an output terminal of the second mixer,

wherein the first controllable current source and the second controllable current source are controlled by the controller.

17. The radar apparatus according to claim 12, wherein the at least one DC offset circuit comprises:

a current source, comprising a first terminal and a second terminal, respectively coupled between a first reference voltage terminal and a second reference voltage terminal; and

a resistor, comprising a first terminal and a second terminal, respectively coupled between the second terminal of the current source and the second reference voltage terminal, and one of the first terminal and the second terminal of the resistor is further coupled to an output terminal of the mixer,

wherein the controller is configured to adjust a voltage drop between the first terminal and the second terminal of the resistor.

18. A radar apparatus, comprising:

a transmitter, comprising;

a first sinewave signal generator, configured to generate a first sinewave signal; and

a receiver, configured to receive a transmitting signal transmitted by the transmitter, wherein the transmitting signal comprises the first sinewave signal, and the receiver comprises;

a second sinewave signal generator, configured to generate a second sinewave signal according to an amplitude of the transmitting signal or an amplitude of a received transmitting signal; and

a correcting circuit, coupled to the second sinewave signal generator, and configured to correct a leakage situation of the received transmitting signal based on the second sinewave signal, wherein a phasor corresponding to the leakage situation in a sinewave form is related to a phasor of the second sinewave signal,

wherein the second sinewave signal generator dynamically adjusts an amplitude of the second sinewave signal in response to an amplitude corresponding to the leakage situation being greater than a threshold.

19. A radar apparatus, comprising:

a transmitter, comprising;

a first sinewave signal generator, configured to generate a first sinewave signal; and

a receiver, configured to receive a transmitting signal transmitted by the transmitter, wherein the transmitting signal comprises the first sinewave signal, and the receiver comprises;

a second sinewave signal generator, configured to generate a second sinewave signal according to an amplitude of the transmitting signal or an amplitude of a received transmitting signal;

a correcting circuit, coupled to the second sinewave signal generator, and configured to correct a leakage situation of the received transmitting signal based on the second sinewave signal, wherein a phasor corresponding to the leakage situation in a sinewave form is related to a phasor of the second sinewave signal; and

a control circuit, coupled to the second sinewave signal generator, and configured to determine location information of an external object according to a phase corresponding to the leakage situation.