Transient and steady state phase similarity of the AEGIS AN/SPY-1 crossed-field amplifier (CFA) as a function of duty cycle

The CFA duty cycle value controls the heating and cooling of the anode vanes, leading to thermal expansion and contraction, and thereby impacting the phase characteristic of the device. CFA phase similarity with respect to duty changes are therefore important for CFAs that are installed in radar systems that use rapid duty cycle changes. Because the AEGIS AN/SPY-1 Radar System operates using rapid duty cycle changes, the AEGIS AN/SPY-1 CFA must maintain (1) transient phase similarity, and (2) steady state phase similarity, both as a function of duty cycle. Until recently, test equipment limitations prevented the transient phase similarity data from being accurately collected. Engineering testing was conducted at Naval Surface Warfare Center to determine the phase similarity characteristics of the AEGIS CFA with respect to duty cycle changes. A sample of AEGIS AN/SPY-1 CFAs were characterized using a new test method, and the data was analyzed to determine how much the phase similarity changed in the device with changes in duty cycle. This paper describes the test equipment used, the testing procedure used, along with the phase similarity data with respect to duty cycle, for the AEGIS AN/SPY-1 CFA. It is believed that this is the first time instantaneous phase response to duty cycle testing has ever been done.