Method for achievement of a multigigawatt peak power by compressing microwave pulses of a relativistic backward-wave oscillator in a helical waveguide

Abstract

We show theoretically that the use of a circular oversized waveguide with a helically corrugated internal surface as a dispersive medium ensures efficient compression of frequency-modulated microwave pulses up to peak powers of about 10 GW. According to the calculations, a pulse with the required frequency modulation can be obtained in a relativistic backward-wave oscillator operated in the 3-cm wavelength range and producing an output power of hundreds of megawatts. In a demonstration experiment, a 80-ns pulse of kilowatt power with frequency modulation in a 5% band was compressed to a 1.5-ns pulse with a 25-fold power amplification

Method for calculation of helical-waveguide eigenmodes on the basis of solving the equivalent two-dimensional problem by field expansion in circular-waveguide modes

“…The dispersion characteristics of the working modes in the calculated waveguides were also measured in the corresponding experiments [8,9]. As a rule, the relative measurement error and the structure manufacturing accuracy ranged from 0.2 to 0.3%.…”

“…Another example of using the proposed method is the calculation of the dispersion characteristic of a helical waveguide with five-start corrugation and an enlarged cross section, which is the key element of the compressor of frequency-modulated microwave pulses up to multigigawatt values of the peak power [9,10]. Due to the requirements imposed on the electric strength, this system is more oversized than the gyro-TWT waveguide.…”

“…At present, two research lines, in which helically corrugated waveguides play the key role, are intensely worked upon. The first line is development of gyrodevices with high levels of a continuous-wave or average power and a wide frequency tuning range in the millimeter-wave band [8], while the second one is creation of a passive compressor of microwave pulses to achieve the multigigawatt power level in 3-cm and 8-mm wavelength bands [9,10]. Development of the above-mentioned devices is impossible without accurate and relatively fast calculations of electrodynamic characteristics of helical waveguides, of which the dispersion characteristics and field structure of eigenmodes are the most important.…”

“…To verify the proposed method, the results obtained by its use are compared with the results of the three-dimensional calculations performed earlier in [8,9].…”

Calculation and optimization of three-dimensional waveguide systems by the integral equation method

“…Such structures are of interest for a number of applications in the field of high-power microwave electronics [9,10]. This work discusses the characteristics of some helical waveguides which are employed as the interaction space in gyrodevices (gyro-TWTs and gyro-BWOs) [11,12], as well as waveguides used to compress frequencymodulated pulses with a gigawatt power level [13,14].…”