Phase Synchronization Between Remote Microwave Systems

Compared with the traditional monostatic radar, the bistatic and multistatic radar provide more excellent performance. At the same time, some challenging technical problems have been also introduced, among which the phase synchronization is the fundamental technique for the excellent performance of modern radar. With the increasing demand of practical application, remote phase synchronization independent of the distance change is becoming more and more important, especially when there’s relative motion existing between the distributed remote microwave systems. In addition, in the application of beamforming and phased arrays, phase synchronization also plays an important role.This paper mainly focuses on the phase synchronization scheme based on the remote distributed phase locked loops. The scheme of the synchronization principle is introduced in this paper, and the phase domain analysis model based on the principle is also given, as well as the derivation of stable-state phase difference response of the system under different motion conditions. Furthermore, simulation model is established using the Simulink tool embedded in Matlab, through which the system responses under different motion conditions are simulated, and the simulation results coincide with the theoretical analysis. To validate the results of theoretical analysis and the simulation in practice, a prototype system operating in UHF band is implemented, using which some experiment measurements have been conducted in a microwave chamber to verify the relationship between the phase synchronization and the remote microwave systems with relative motion.All the theoretical, simulation and experimental results show that such system is robust when the remote systems are in relatively static state or there’s uniform motion existing between the subsystems, and the phase synchronization can be obtained. Based on this analysis and experimental result, in this paper, a scheme of compensating for the phase difference due to the uniform motion is proposed. An additional phase loop with a special motion compensator can be introduced to the current remote phase locked loops, so that the phase synchronization can be established between such moving systems. Theoretical analysis proved the feasibility to physically implement such systems. The proposed approach provides a solution to the technical difficulty in obtaining a practical phase coherence system with uniform motions, and can be potentially used in spaceborne bistatic and multistatic SAR applications.