Wave transformation in a multimode waveguide with corrugated walls

Calculation and Optimization of 3D Waveguiding System with Help of Integral Equation Method

“…The length of theconverter was taken equal to four deformation periods. For such a short converter the amplitude of deformation is rather big, and the simplest method of perturbation [9] does not provide a required accuracy. In our case (r 0 =7.45 mm, frequency f=30 GHz), it gives the amplitude and the period of deformation equal to 0.93 mm and 28.7 mm respectively.…”

“…In this method (proposed by N.F. Kovalev), the electromagnetic field inside a waveguide is represented as a superposition of the spatial harmonics (Floquet harmonics) whose amplitudes and propagation constants are determined by the dispersion equation which appears when satisfying the approximated boundary conditions for the fields' components at the inner surface [9]. With assumption of sufficiently small perturbation of the walls (l<<d, l<<l, where l=2pc/w is the free-space wavelength), the corresponding boundary conditions can be found from expansion of the electric field near the surface as a Taylor series.…”

Efficient Output Mode Converter for 30 GHz Gyroklystron at IAP

“…The efficient conversion at a short length is reached in a helically corrugated waveguide with five azimuth variations due to degeneration of the mentioned pair of modes. The principle of this class of mode converters is described in [4,5]. The difference of Bessel roots 2 Á m 53 Àm 04 m 53 þm 04 is just about 5%, where μ 04 and μ 53 are corresponding roots of Bessel equation J m 0 m ð Þ ¼ 0 for TE 04 and TE 53 modes respectively.…”

Microwave Devices With Helically Corrugated Waveguides

“…Such a corrugation provides asymmetry of the wave dispersion for circularly polarized modes resulting in additional mode selection and control of their dispersion characteristics. These properties make waveguides with a helical corrugation attractive for a large number of applications 1,2 . In particular, they have recently been successfully used as interaction regions in gyro-TWTs 3,4 , gyro-BWOs 4, 5 and as a dispersive medium for passive microwave pulse compression 6 .…”