Systems and methods for calibrating phased array antennas

A calibration circuit for an antenna system having an antenna array, the calibration circuit comprising:

• an input/output (I/O) interface configured to communicate between the calibration circuit and a controller of the antenna system;
• a first switch and a second switch;
• a signal source configured to generate an output test signal;
• a receiver configured to receive a return test signal;
• a first test path port and a second test path port configured to couple the calibration circuit into a test path of the antenna system;
• and
• a calibration controller configured to:
• during a receive path calibration:
• control the first switch to route the output test signal from the signal source to the first test path port;
• and
• control the second switch to route the return test signal from the second test path port to the receiver;
• and
• during a transmit path calibration:
• control the second switch to route the output test signal from the signal source to the second test path port;
• and
• control the first switch to route the return test signal from the first test path port to the receiver,
• wherein at least one of the receiver and the calibration controller generates a receive test path measurement based on the output test signal and the return test signal during the receive path calibration and output the receive test path measurement to the controller via the I/O interface, and
• wherein at least one of the receiver and the calibration controller generates a transmit test path measurement based on the output test signal and the return test signal during the transmit path calibration and output the transmit test path measurement to the controller via the I/O interface.