Particle-in-cell (PIC) simulation of a two-foil magnetoinsulated vircator is carried out. Evolution of electron phase portrait has been studied. Formation of two regions with a squeezed state of electron beam is observed, separated from each other by an electronic phase vortex. The power of two-foil vircator's microwave generation was calculated. It is demonstrated that in the phase vortex mode, the power of vircator's microwave radiation may excel the outcome power of a usual one-foil vircator by two times. The spectral characteristics of two-foil vircators were studied. It was found that it is necessary to change the energy of electrons for the variation of primary microwave generation frequency.
