BACKGROUND

Radar detection involves transmitting electromagnetic energy and receiving reflected portions of the transmitted electromagnetic energy. Techniques for transmitting electromagnetic energy in radar systems include impulse, chirp, and stepped frequency techniques. Stepped frequency radar has traditionally been implemented by repeatedly scanning over the same frequency range using the same step size. For example, a frequency burst of stepped frequency pulses over the same frequency range with the same step size and the same number of steps is continuously repeated to implement stepped frequency radar. Although traditional stepped frequency radar works well, there is a need to expand the capabilities of stepped frequency radar.

SUMMARY

A method for monitoring a health parameter in a person using a radar system is disclosed. The method involves performing stepped frequency scanning below the skin surface of a person using at least one transmit antenna and a two-dimensional array of receive antennas, the stepped frequency scanning being performed using frequency steps of a first step size, changing the first step size to a second step size in response to a change in reflectivity of blood in a blood vessel of the person, wherein the second step size is different from the first step size, performing stepped frequency scanning below the skin surface of the person using the at least one transmit antenna and the two-dimensional array of receive antennas and using the second step size after the step size is changed from the first step size to the second step size, and outputting a signal that corresponds to a blood pressure level in the person in response to the stepped frequency scanning at the first step size and at the second step size.

In an embodiment, the method involves evaluating blood reflectively data generated from the stepped frequency scanning, and the step size is changed in response to the blood reflectivity data evaluation.

In an embodiment, the step size is changed from the first step size to the second step size in response to feedback information from the stepped frequency scanning, wherein the feedback information corresponds to a change in reflectivity of the blood in the blood vessel of the person.

In an embodiment, the step size is changed from a first step size to a second step size in a couple of repetition intervals, T.

In an embodiment, the stepped frequency scanning is in a frequency range of 2-6 GHz.

In an embodiment, the stepped frequency scanning is in a frequency range of 122-126 GHz.

In an embodiment, the step size is changed in accordance with a digital frequency control signal.

In an embodiment, the method involves evaluating data generated from the stepped frequency scanning, and wherein the step size is changed in response to the data evaluation.

A health monitoring system is also disclosed. The health monitoring system includes a radio frequency (RF) front-end, and a digital baseband system, the RF front-end includes at least one transmit antenna and a two-dimensional array of receive antennas, the RF front-end configured to perform stepped frequency scanning below the skin surface of a person using the at least one transmit antenna and the two-dimensional array of receive antennas, the stepped frequency scanning being performed using frequency steps of a first step size, change the first step size to a second step size in response to a digital frequency control signal received from the digital baseband system, wherein the second step size is different from the first step size, perform stepped frequency scanning below the skin surface of the person using the at least one transmit antenna and the two-dimensional array of receive antennas and using the second step size after the step size is changed from the first step size to the second step size, and the digital baseband system is configured to change the digital frequency control signal that is provided to the RF front-end from a first digital frequency control signal that corresponds to the first step size to a second digital frequency control signal that corresponds to the second step size in response to blood reflectivity signals that are generated by the RF front-end from the stepped frequency scanning, and output a signal that corresponds to a blood pressure level in the person in response to the stepped frequency scanning at the first step size and at the second step size.

In an embodiment of the stepped frequency radar system, the frequency range is in the range of 2-6 GHz.

In an embodiment of the stepped frequency radar system, the frequency range is in the range of 122-126 GHz.

Another method for monitoring a health parameter in a person using a radar system is disclosed. The method involves performing stepped frequency scanning below the skin surface of a person using at least one transmit antenna and a two-dimensional array of receive antennas, the stepped frequency scanning being performed across a frequency range using frequency steps of a step size, changing at least one of the step size and the frequency range in response to a change in reflectivity of blood in a blood vessel of the person, performing stepped frequency scanning below the skin surface of the person using the at least one transmit antenna and the two-dimensional array of receive antennas and using the changed at least one of the step size and the frequency range, and outputting a signal that corresponds to a blood pressure level in the person in response to the stepped frequency scanning.

In an embodiment, the method involves evaluating blood reflectively data generated from the stepped frequency scanning across the frequency range, and the at least one of the step size and the frequency range is changed in response to the blood reflectivity data evaluation.

In an embodiment, the step size is changed from a first step size to a second step size in response to feedback information from the stepped frequency scanning, wherein the feedback information corresponds to a change in reflectivity of the blood in the blood vessel of the person.

In an embodiment, the step size is changed from a first step size to a second step size in a couple of repetition intervals, T.

In an embodiment, the frequency range is in the range of 2-6 GHz.

In an embodiment, the frequency range is in the range of 122-126 GHz.

In an embodiment, the at least one of the step size and the frequency range is changed in accordance with a digital frequency control signal.

In an embodiment, the step size is changed from a first step size to a second step size, wherein the second step size is different from the first step size.

Other aspects in accordance with the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention.

