Digital modulator radar transmitter leakage cancellation using frequency temporal filtering

1 . A method performed by a radar system, the method comprising:

continuously transmitting a radar signal from a transmit antenna toward a target, wherein during a first transmission frame the radar signal is transmitted using a first frequency subband;

transmitting the radar signal using a second frequency subband during a second transmission frame, and continuing to transmit the radar signal in a continuous manner during each subsequent transmission frame, with the transmit antenna switching to a different frequency subband in each transmission frame;

ensuring that, during each transmission frame, the transmit antenna and a receive antenna are never active in the same frequency subband at the same time;

operating the receive antenna, during each transmission frame after the first transmission frame, in the frequency subband used by the transmit antenna in an immediately preceding transmission frame, such that the receive antenna is always tuned to the subband used by the transmit antenna in the immediately preceding frame, and at no point are the transmit antenna and receive antenna active in the same subband during the same frame; and

receiving a radar return from the target at the receive antenna, the radar return based upon the radar signal reflecting from the target.

2 . The method of claim 1 , further comprising dividing a radar frequency band into N frequency subbands, where N is at least two, wherein the transmitting further comprises using different frequency subbands in contiguous transmission frames.

3 . The method of claim 2 , further comprising incrementally increasing the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the transmit antenna resets to the first frequency subband for another iteration.

4 . The method of claim 2 , wherein the transmit antenna is configured to incrementally decrease the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the transmit antenna resets to the first frequency subband for another iteration.

5 . The method of claim 2 , further comprising, for a given transmission frame, randomly selecting a frequency subband from among the N frequency subbands, wherein the randomly selected subband is different than a frequency band used in a transmission frame immediately preceding the given transmission frame.

6 . The method of claim 1 , wherein the radar system is configured for phase-modulated continuous wave (PMCW) operation.

7 . The method of claim 1 , wherein the radar system is configured for orthogonal frequency division multiplexing (OFDM) operation.

8 . A radar system comprising:

a transmit antenna that transmits a radar signal toward a target, the transmit antenna being configured to:

continuously transmit the radar signal, wherein during a first transmission frame the radar signal is transmitted using a first frequency subband;

transmit the radar signal using a second frequency subband during a second transmission frame, and continuing to transmit the radar signal in a continuous manner during each subsequent transmission frame, with the transmit antenna switching to a different frequency subband in each transmission frame;

ensure that, during each transmission frame, the transmit antenna and a receive antenna are never active in the same frequency subband at the same time; and

a receive antenna that receives a radar return from the target, the radar return based upon the radar signal reflecting from the target;

wherein the receive antenna is configured to operate, during each transmission frame after the first transmission frame, in the frequency subband used by the transmit antenna in an immediately preceding transmission frame, and at no point are the transmit antenna and the receive antenna active in the same subband during the same frame.

9 . The radar system of claim 8 , further comprising N frequency subbands, where N is at least two, wherein the transmit antenna is configured to transmit the radar signal using different frequency subbands in contiguous transmission frames.

10 . The radar system of claim 9 , wherein the transmit antenna is configured to incrementally increase the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the transmit antenna resets to the first frequency subband for another iteration.

11 . The radar system of claim 9 , wherein the transmit antenna is configured to incrementally decrease the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the transmit antenna resets to the first frequency subband for another iteration.

12 . The radar system of claim 9 , wherein the transmit antenna is configured to randomly select a frequency subband from among the N frequency subbands, wherein the randomly selected subband is different than a frequency band used in a transmission frame immediately preceding the given transmission frame.

13 . The radar system of claim 8 , wherein the radar system is configured for phase-modulated continuous wave (PMCW) operation.

14 . The radar system of claim 8 , wherein the radar system is configured for orthogonal frequency division multiplexing (OFDM) operation.

15 . A radar system comprising:

a transmit antenna;

a receive antenna; and

a hardware logic component that is configured to perform acts comprising:

causing the transmit antenna to continuously transmit a radar signal toward a target, wherein during a first transmission frame the radar signal is transmitted using a first frequency subband; and

causing the transmit antenna to transmit the radar signal using a second frequency subband during a second transmission frame, and continuing to transmit the radar signal in a continuous manner during each subsequent transmission frame, with the transmit antenna switching to a different frequency subband in each transmission frame;

ensuring that, during each transmission frame, the transmit antenna and the receive antenna are never active in the same frequency subband at the same time;

causing the receive antenna to operate during each transmission frame after the first transmission frame in the frequency subband used by the transmit antenna in the immediately preceding transmission frame, such that the receive antenna is always tuned to the subband used by the transmit antenna in the immediately preceding frame, and at no point are the transmit antenna and receive antenna active in the same subband during the same frame; and

detecting a radar return from the target at the receive antenna, the radar return based upon the radar signal reflecting from the target.

16 . The radar system of claim 15 , further comprising N frequency subbands, where N is at least two, wherein the hardware logic component is configured to cause the transmit antenna to transmit the radar signal using different frequency subbands in contiguous transmission frames.

17 . The radar system of claim 16 , wherein the hardware logic component is configured to incrementally increase the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the hardware logic component resets to the first frequency subband for another iteration.

18 . The radar system of claim 16 , wherein the hardware logic component is configured to incrementally decrease the frequency subband used during each successive transmission frame until the Nth frequency subband is used, after which the hardware logic component resets to the first frequency subband for another iteration.

19 . The radar system of claim 16 , wherein the hardware logic component is configured to randomly select a frequency subband from among the N frequency subbands, wherein the randomly selected subband is different than a frequency subband used in a transmission frame immediately preceding the given transmission frame.

20 . The radar system of claim 15 , wherein the hardware logic component is configured to monitor a transmit antenna subband sequence and provide to the receive antenna a receive antenna subband sequence that lags the transmit antenna subband sequence by one transmission frame.