Research on Middle Field Calibration Technology Based on Phase Inverted Method

keywords:method of middle-field  phased antenna  inverse phase  chipping  calibration

Abstract:Array calibration is a key step in research on phased array antenna. Compared with other calibration methods, middle-field calibration uses fewer devices and has higher test efficiency, so it has a wide range of application. Usually, three-state switches (transmission-state, receiving-state and load-state) are designed and used in T/ R modules. During middle-field test, da-ta of amplitudes and phases in all transmission channels (receiving channels) may be obtained by “one by one” method (switch on receive channels of T/ R modules one by one and the non-tested channels is in the load-state). However, isolation of switch is limited in the array composed of “chipping” T/ R modules. So signals to be tested will be interfered by leakage signals severely, and faults cannot even be identified normally. In this article, a middle-field calibration based on inverse phase method is proposed and its error magnitude is analyzed. Finally, this method is verified valid by patterns tested in far-field.