Study Of Real-time Calibration In Phased Array Antenna Testing System

Phased array antenna is the core of phased array radar, and measurement of itsradiation characteristics is a complex technical problem. When the number of phased arrayantenna unit is very large, using multi-probe testing technology can greatly improve theefficiency of the testing system. However, the multi-probe test technology has strictrequirement of the amplitude and phase consistency of testing channel.To solve this problem, this paper focuses on network features of multi-probe switcharray test channel. And, according to the scattering characteristics of reciprocal microwavenetwork and cascade nature of microwave network, we proposed the OSM calibrationmethod which is using single-port reflection characteristics to derive channel transmissioncharacteristics. After that, we verified this calibration method by ADS simulation. And also,we conducted experiments test by using OSM real-time calibration kit composed ofsingle-pole four-throw switch, open circuit device, short circuit device, and matched load.The simulated and measured results proved the correctness of this method. When the testingsystem operation, accessing the OSM real-time calibration kit to each test channelseparately, then, sequentially in situ measurements for port reflective properties of each testchannel when which is in the state of terminal open, short and matching by the hostcomputer. According to the OSM calibration method proposed in this paper, we can obtainthe transmission parameter of each channel in real time. And then the host computerexecutes calibration and compensation to the magnitudes and the phases of all the channelsto guarantee the consistency.The OSM calibration method proposed in this paper can be used for real-timecalibration of test channel in phased array antenna testing system. The method not onlyguarantees the consistency of all the test channels’ amplitudes and phases, but also greatlyimproves testing speed and accuracy of the testing system. Therefore, research of this paperhas important application value and practical significance for the calibration work of largephased array antenna.