Calibration and monitoring in cascaded radar system without local oscillator signal distribution

A radar monolithic microwave integrated circuit (MMIC), comprising:

• a control logic configured to set the radar MMIC in a plurality of operation modes, including a radar operation mode and at least one of a monitoring mode or a calibration mode;
• a local oscillator (LO) input terminal configured to receive a first LO signal from outside of the radar MMIC during a mode in which LO distribution of the first LO signal is enabled;
• a clock input terminal configured to receive a system clock signal during the plurality of operation modes;
• an LO generation circuit configured to generate a second LO signal based on the system clock signal;
• and
• an LO switching circuit configured to:
• receive the first LO signal from the LO input terminal, the second LO signal from the LO generation circuit, and a first control signal indicating whether the LO distribution of the first LO signal is enabled or disabled,
• output the first LO signal based on the first control signal indicating that the LO distribution of the first LO signal is enabled, and
• output the second LO signal based on the first control signal indicating that the LO distribution of the first LO signal is disabled,
• wherein the LO distribution of the first LO signal is enabled during the radar operation mode of the radar MMIC and disabled during at least one of the calibration mode or the monitoring mode of the radar MMIC.

A cascaded radar system, comprising:

• a primary radar monolithic microwave integrated circuit (MMIC);
• and
• a secondary radar MMIC,
• wherein the primary radar MMIC comprises:
• a first control logic configured to set the radar MMIC in one of a first plurality of operation modes, the first plurality of operation modes including a first radar operation mode, and at least one of a first monitoring mode or a first calibration mode;
• a system clock terminal configured to receive a system clock signal;
• a first local oscillator (LO) generation circuit configured to generate a first LO signal based on the system clock signal, wherein the first LO generation circuit is configured to generate the first LO signal as a first frequency ramp signal during the first radar operation mode;
• a clock output terminal configured to output the system clock signal for system clock distribution to the secondary MMIC;
• an LO output terminal configured to output the LO signal for LO distribution to the secondary MMIC;
• and
• an LO distribution circuit coupled to the LO output terminal and configured to receive the first LO signal from the first LO generation circuit and enable or disable the LO distribution of the first LO signal based on a first control signal indicating whether the LO distribution of the first LO signal is enabled or disabled,
• wherein the first control logic is configured to provide the first control signal to the LO distribution circuit for enabling or disabling the LO distribution, wherein the first control signal is configured to enable the LO distribution during the first radar operation mode of the primary radar MMIC and disable the LO distribution during at least one of the first calibration mode or the first monitoring mode of the primary radar MMIC.

A radar monolithic microwave integrated circuit (MMIC), comprising:

• a control logic configured to set the radar MMIC in a plurality of operation modes, including a radar operation mode and at least one of a monitoring mode or a calibration mode;
• a local oscillator (LO) input terminal configured to receive a first LO signal from outside of the radar MMIC during a mode in which LO distribution of the first LO signal is enabled;
• a clock input terminal configured to receive a system clock signal during the plurality of operation modes;
• an LO generation circuit configured to generate a second LO signal based on the system clock signal;
• an enabling-disabling circuit configured to receive a control signal indicating whether the LO distribution of the first LO signal is enabled or disabled, enable the second LO signal based on the control signal indicating that the LO distribution of the first LO signal is disabled, and disable the second LO signal based on the control signal indicating that the LO distribution of the first LO signal is enabled;
• and
• a combiner circuit configured to receive the first LO signal or the second LO signal based on the LO distribution being enabled or disabled, respectively;
• and
• a radar circuit coupled to the combiner circuit and configured to receive either the first LO signal or the second LO signal,
• wherein the LO distribution of the first LO signal is enabled during the radar operation mode of the radar MMIC and disabled during at least one of the calibration mode or the monitoring mode of the radar MMIC.