Research On The Stealth Technology Of Phase Modulating Surface

In this paper, the stealth mechanisms of phase modulating surface(PMS) are deeply studied, and the phase characteristics of the element of reflect array are researched. Two types of PMSs are proposed. Both simulations and measurements demonstrate the validity of these two PMSs on stealth application.The main achievements are as the followings:1. The field synthesis principle of array antenna is studied, and the RCS reduction principle of passive phase modulating surface(PPMS) is analyzed with arrays of different phase distribution at normal incidence and oblique incidence. It provides a theoretical basis for phase modulation stealth technology research and design.2. The time-domain and frequency-domain characteristics of the narrowband signal and wideband signal with phase modulation are analyzed, and qualitative analysis of the RCS reduction principles of active phase modulating surface(APMS) is obtained. The comparative analysis of different modulating schemes is done for determining the optimal modulating means.3. PPMSs with different phase distributions are studied, and one PPMS with random phase distribution is proposed. Design conditions to obtain effective RCS reduction are analyzed. With broadband approaches studied, a three-layer stacked cross patches PPMS is proposed, and both the simulations and experiments demonstrate the validity of this design. The results show that the PMS has the RCS reduction effect within 7~20GHz frequency range. A conformal PPMS is designed based on the study of cylindrical surface, and simulation shows the effectiveness of the design.4. The implementation method of active electromagnetic material is studied, and an aperture-coupled microstrip patch unit is proposed as the element of APMS. With design method of active control circuits being studied, a 180° reflection phase switcher is proposed by the use of open, short-circuit converter, and equivalent circuit model is established and analyzed. Compared to conventional APMS, the method proposed, is advanced in stability and flexibility by using aperture-coupled microstrip patch array, in the meantime, avoiding the use of switching the thickness of reflection surface. A unit test device is designed for unit testing. An array test environment is built in microwave chamber for testing the array. The measurement results of element and array keep consistent. Both simulations and measurements prove the validity of the design.5. According to the detection characteristics of radar echo, an adaptive modulation control module is proposed. The output of single-bit Instantaneous frequency measurement(IFM) module is ultrilized as the input of decision module. Theoutput of IFM module when receives broadband radar signal is simulated, and the results show that the wideband signal waveform has obvious characteristics comparating to narrowband waveform. The impact of delay of adaptive modulating module on signal detection is researched, and the requirements are proposed which meet the practical needs.