Dispersion Properties of a Backward Wave Oscillator with Modified Rectangular Corrugations

In this paper, a modified rectangularly corrugated slow wave structure (MRCSWS) is investigated numerically where the dispersion properties of the symmetric transverse magnetic (TMoi - TM03) modes are considered. The structural dimensions of the MRCSWS are taken for operating the structure in x-band frequency range. For the operating mode, the reduction of group velocity causes the increment in interaction impedance which may be obtained by increasing the energy inside the cavity of the slow wave structure (SWS). Physically, the stored energy can he increased by extending the area of the cavity keeping the period fixed. Here, the area of the inner cavity of a rectangularly corrugated structure is varied for a fixed corrugation period. Results show that the dispersion curves as well as the oscillating frequency change as the area of the inner cavity is varied. For the small increment of the cavity area, the group velocity of the operating mode reduces which can be used to increase the overall efficiency of the structure as the stored energy of the SWS increases when the group velocity is reduced.