An Amplitude-Phase Measurement Method for Cross-Eye Jammers

The measurement and compensation of the amplitude-phase parameters (i.e., amplitude ratio and phase difference) are crucial to the performance of cross-eye jammers. An amplitude-phase measurement method for cross-eye jammers is presented in this article, including a measurement circuit and a calculation method. The proposed measurement method realizes accurate and unambiguous amplitude-phase measurement for cross-eye jammers at low cost and low complexity. The proposed measurement circuit is designed by utilizing the reciprocity of RF passive components. The structure of the measurement circuit is simple. And the systematic errors are avoided. The proposed calculation method for the phase difference is based on comparing the theoretical errors of two candidate phase difference. The ambiguity of the phase difference in the range from -180(degrees) to 180(degrees) is overcome by combining two forms of signal synthetization. The errors of the proposed measurement method are clarified through theoretical derivations and verified through Monte Carlo simulations. The measurement experiments of a cross-eye jammer prototype indicate that the errors of the proposed measurement method are basically within +/- 0.3 dB and +/- 5(degrees) for the amplitude ratio and the phase difference, respectively, when in comparison to the measurement results obtained by a vector network analyzer (VNA).