Generation of 3 GW microwave pulses in X-band from a combination of a relativistic backward-wave oscillator and a helical-waveguide compressor

Abstract

The phenomenon of passive compression of frequency-modulated (FM) pulses in a dispersive media (DM) was used to increase the peak microwave power up to the multigigawatt level A helically corrugated waveguide was used as the DM, while a relativistic X-band backward-wave oscillator (RBWO) with a descending-during-the-pulse accelerating voltage served as a source of FM pulses Compression of pulses down to a halfwidth of 2 2 ns accompanied by a 4 5-fold power increase up to a value of about 3 2 GW has been demonstrated

Design and experiments of a five-fold helically corrugated waveguide for microwave pulse compression

“…A five-fold helically corrugated compressor was used as the dispersive medium where a 700 MW X-band relativistic backward wave oscillator (RBWO) served as a 20ns duration source of the frequency modulated pulses. Compression of pulses down to a halfwidth of 2.2 ns accompanied by a 4.5-fold power increase up to a value of ~3.2 GW was achieved [10]. Results have been presented demonstrating that it may be possible to use a 5-fold helically corrugated waveguide compressor combined with a RBWO to produce peak powers in excess of 10 GW in X-band.…”

Periodic GW level microwave pulses in X-band from a combination of a relativistic backward wave oscillator and a helical waveguide compressor

“…These relatively high-order modes ensured sufficient RF breakdown strength at gigawatt power level. The inner surface of the waveguide in cylindrical coordinates r, , z had the following form: r( ,z) = 31.5+2.7sin(2 z/32.4 -5 ) (2) (all dimensions in millimeters). The pulse compressor consisted of 4 aluminum sections and had a total length of regular corrugation of 972 mm, bounded on each side by three-period sections with linearly increasing/decreasing amplitude of corrugation for adiabatic conversion.…”

“…Pulse compression technology that converts long duration, low power pulses into short, high peak power pulses is commonly used in applications that require high peak power and pulsed operation such as radar systems [1]. Gigawatt level microwave radiation can be achieved by a frequency-swept multi-megawatt pulse generated by a high power vacuum electronic device acting as the input source for a microwave pulse compressor based on a high fold helically corrugated waveguide (HCW) [2]. Such gigawatt level signals are otherwise extremely difficult to realise.…”

Circular polariser for use in a gyro‐travelling wave amplifier

“…Helically corrugated waveguide interaction regions [2–9] radically alter the dispersion relation of the interacting mode such that it matches the electron beam dispersion [10] over a range of up to 20% of the centre frequency. Recent studies [11–16] have concentrated on broadband applications and as a consequence these studies have required high‐frequency waveguide components with performance optimised for broadband, high‐power operation. One of these components is the elliptical converter (used to generate circular polarised radiation from linear [17]).…”