Antenna device and method for calibrating antenna device

1. An antenna device, comprising:

an antenna array, comprising:

a first antenna unit and a second antenna unit for transmitting or receiving a first signal; and

a probe configured to receive the first signal from the first antenna unit and the second antenna unit or transmit the first signal to the first antenna unit and the second antenna unit, wherein the first antenna unit and the second antenna unit are respectively spaced apart from the probe by a first distance; and

a control circuit coupled to the antenna array, the control circuit calibrates the first antenna unit and the second antenna unit according to a first beat frequency of the first signal corresponding to the first distance.

2. The antenna device of claim 1 , wherein the first signal is a frequency-modulated continuous-wave (FMCW).

3. The antenna device of claim 1 , wherein the step of calibrating the first antenna unit and the second antenna unit according to the first beat frequency of the first signal corresponding to the first distance comprises:

adjusting the first signal to make the first signal to reach one of a preset maximum value and a preset minimum value at the first beat frequency.

4. The antenna device of claim 1 , wherein the antenna array further comprises a third antenna unit spaced apart from the probe by the first distance and configured to transmit or receive the first signal, and the control circuit is further configured to perform:

disabling the second antenna unit after calibrating the first antenna unit and the second antenna unit; and

calibrating the third antenna unit according to the first beat frequency corresponding to the first antenna unit and the third antenna unit.

5. The antenna device of claim 1 , wherein the antenna array further comprises:

a fourth antenna unit for transmitting or receiving a second signal; and

a fifth antenna unit for transmitting or receiving the second signal, wherein the fourth antenna unit and the fifth antenna unit are respectively spaced apart from the probe by a second distance, and the second distance is different from the first distance, wherein

the control circuit calibrates the fourth antenna unit and the fifth antenna unit according to a second beat frequency of the second signal corresponding to the second distance while calibrating the first antenna unit and the second antenna unit.

6. The antenna device of claim 5 , wherein the second signal is a frequency-modulated continuous-wave (FMCW).

7. A method for calibrating an antenna device, comprising:

transmitting or receiving a first signal through a first antenna unit and a second antenna unit;

receiving the first signal from the first antenna unit and the second antenna unit or transmitting the first signal to the first antenna unit and the second antenna unit by a probe, wherein the first antenna unit and the second antenna unit are respectively spaced apart from the probe by a first distance; and

calibrating the first antenna unit and the second antenna unit according to a first beat frequency of the first signal corresponding to the first distance.

8. The method of claim 7 , wherein the first signal is a frequency-modulated continuous-wave (FMCW).

9. The method of claim 7 , wherein the step of calibrating the first antenna unit and the second antenna unit according to the first beat frequency of the first signal corresponding to the first distance comprises:

adjusting the first signal such that the first signal reaches a preset maximum value at the first beat frequency.

10. The method of claim 7 , further comprising:

disabling the second antenna unit after calibrating the first antenna unit and the second antenna unit;

transmitting or receiving the first signal through a third antenna unit; and

calibrating the third antenna unit according to the first beat frequency corresponding to the first antenna unit and the third antenna unit.

11. The method of claim 7 , further comprising:

transmitting or receiving a second signal through a fourth antenna unit and a fifth antenna unit, wherein the fourth antenna unit and the fifth antenna unit are respectively spaced apart from the probe by a second distance, and the second distance is different from the first distance; and

calibrating the fourth antenna unit and the fifth antenna unit according to a second beat frequency of the second signal corresponding to the second distance while calibrating the first antenna unit and the second antenna unit.

12. The method of claim 11 , wherein the second signal is a frequency-modulated continuous-wave (FMCW).