Combined radio altimeter and doppler radar with surface-mountable antenna array and loop-back calibration

Abstract

A radio device includes a radio frequency (RF) unit and a surface-mountable antenna module coupled to the RF unit via an electrical connector. The RF unit includes first transmit circuitry, first receive circuitry, and a processing unit, and the surface-mountable antenna module includes a housing, second receive circuitry, and second transmit circuitry. During a calibration procedure, the RF unit is configured to output a calibration RF signal via the electrical connector, receive a first bitstream representing a sampled calibration signal via the electrical connector, and determine a time delay associated with the electrical connector based on the digitized calibration signal and the first bitstream. During the calibration procedure, the surface-mountable antenna module is configured to receive the calibration RF signal via the electrical connector, sample the calibration RF signal to generate the sampled calibration signal, and output the sampled calibration signal via the electrical connector as the first bitstream.