Axial mode locking in a harmonic-multiplying, inverted gyrotwystron

When in microwave sources, an open waveguide operating at frequencies close to cutoff is used as a resonator, a number of modes with the same transver se structure, but different axial distribution can be excited by an electro n beam. The width of the resonance curves of these modes broadens as the nu mber of axial variations grows. This leads to overlapping of these,curves a t large axial indexes. As a result, phase locking of such modes may occur A theory describing axial mode locking in gyrodevices is developed. The resu lts of theoretical analysis are compared to a harmonic-multiplying, inverte d gyrotwystron experiment [1], It is shown that such phase-locked operation in a set of modes with overlapping resonance curves can significantly enla rge the bandwidth of gyrodevices, Furthermore, this technique may be broadl y applicable to other devices, which employ cavities with overlapping modes .