With a low guiding magnetic field, highly efficient X-band coaxial superradiant relativistic backward wave oscillator (SR-RBWO) with front-extraction cavity and built-in mode converter is proposed in this paper. The structure used to reduce the field of intense electron beam. To decrease transmission loss microwave power slow (SWS), introduced. inner conductor SWS hollowed out as output waveguide, then, extracted by enters hollow waveguide rather than re-enter output. improvement, conversion...

Abstract In order to achieve better microwave output performance for relativistic magnetrons, cathode material technology suppressing surface emission defects has been developed significantly. However, some commonly used materials, such as graphite, the upper and lower limits of its in RM operation are still unclear. Therefore, this paper, smooth flake graphite varying degrees roughened one tested permanent magnet packaging rising-sun magnetron. Then, particle cell simulations were performed...

In this letter, a novel high-power microwave (HPM) phase shifter (PS) is proposed. The PS based on the principle of tunable electrical length and can shift by turning rotary choke piston in toroidal-shaped phase-shifting segment. simulation results show that linearly over 360 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> frequency range 2.7–2.9 GHz, power handling...

The initial experimental results of asymmetric mode competition in an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band dual-mode relativistic backward wave oscillator (RBWO) operating at the low magnetic field are presented. In experiment, use receiving antennas with different polarization directions allows direct determination mode, and a frequency 10.27 GHz is excited, which good agreement particle-in-cell (PIC) simulation...

An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${X}$ </tex-math></inline-formula> -band superradiant relativistic backward-wave oscillator (RBWO) operating at a low magnetic field with power conversion efficiency exceeding unity is proposed. The device improved from two aspects: beam transmission stability focused by guiding and microwave efficiency. First, gradually decaying axial applied. It could not...

An investigation on the phase locking of S-band relativistic magnetrons with an all-cavity-extraction (ACE-RM) structure is carried out. In order not to disrupt periodic distribution electric fields in resonant cavities, azimuth-uniform coupling introduced, which could achieve a transmission efficiency over 98% at operating frequency, amplitude difference only ±3.3%. Furthermore, particle-in-cell (PIC) simulations demonstrate that when five ACE RMs are interconnected through four such...

An efficient coaxial superradiant relativistic backward wave oscillator (SR-RBWO) operating at a low magnetic field is proposed and studied. In such SR-RBWO, slow structure (SWS) used in the interaction region, can realize stable transmission of intense electron beam (IREB) long region by using relatively guiding field. The existence an inner conductor reduce radial electric near cathode emission which expansion improve quality IREB. According to dispersion relations SWS when radiation...

A preliminary investigation on S-band multiport relativistic magnetron (RM) is carried out, which targeted at the application of high-power microwave (HPM) phased array system. For such system, phase synchronization and stabilization sources are crucial. In proposed RM, HPMs in four independent output ports extracted from same resonant thus having amplitude naturally. Moreover, mode RM fundamental mode, can achieve Gaussian radiation far field directly. Since convertors phase-locked units no...

The power-limiting performances caused by two types of spin waves in the ferrite microstrip limiter are conducted theoretically and experimentally when narrow microwave pulses applied for excitation. theory indicates that responsible nonlinear (NL) power loss primarily characterized bias magnetic fields magnetized ferrite. Thus, simulation limiting responses due to various is performed constructing equivalent NL parameters model. results align well with measurement data can describe distinct limiter.

A cascaded relativistic magnetron array with symmetric feeder structure was first proposed as a multi-port phase-coherent high-power microwave source, which is intrinsically equipped high structural symmetry. Two symmetrically positioned slow-wave structures surround the structure, reduces axial electron drifting in each resonant system and ensures phase-locking process. In this paper, theory of structure-provided coupling coefficient oscillator-required prerequisites. The method evaluated...

Graphite is the most commonly used large-area cathode material in high-power vacuum electron device for its long life and good repetitive-frequency performance, but particle size selection scheme has not been elucidated. Therefore, present work, explosive emission properties of flake graphite large area cathodes with varied sizes are studied. The 320 mesh a current delay reduction 0.2–0.9 ns compared to other samples at same peak voltage. According Murphy–Good equation, performance each...

We propose an oversized coaxial Cherenkov generator to generate ultrashort pulses with extremely high peak power exceeding 100 GW. The oversize factor of the device is about 5, which ensures sufficient handling capacity for and a very beam current, thus driving power. An optimized profiled slow wave structure (SWS) squarely increasing corrugation amplitude, rather than linearly function, uniform SWS slightly larger period are used provide better beam-wave interaction accomplish energy...

An efficient Cherenkov oscillator with gigawatt phase-controlled super-radiance (SR) pulses is studied for the application of coherent summation systems. To obtain SR pulses, an ultra-short seed pulse required to be injected into interaction space from direction collector, which substitutes impact spontaneous emission front edge electron beam. It means that, a conventional oscillator, injection and output need share same channel. Therefore, additional quasi-optical reflection system needed...

We propose a novel cross-band high-power microwave (HPM) generator which is based on the relativistic magnetron (RM) with all cavity axial extraction and radial three-cavity transit-time oscillator (TTO). A foil structure used to isolate output microwaves of RM TTO. regulating ring introduced before anode block adjust resonant frequency RM. downstream endcap added collect leakage current from delay decrease in power. The particle-in-cell simulations show that as diode voltage 420 kV, 11.4...

The magnetic properties of 50 nm Ni80Fe20 deposited on Cu underlayers with different thicknesses by obliquely sputtering were studied. It was found that the in-plane uniaxial anisotropy (IPUMA) film can be induced sputtered underlayer under NiFe layer. IPUMA field varies between 20 Oe and 40 when thickness from 5 to nm. permeability spectrum results show damping factor increases increasing thickness. This indicates changing is an effective method adjust in dynamic magnetization process thin films.

Simulations and experiments of an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S}$ </tex-math></inline-formula> -band TEM-output relativistic magnetron (RM) driven by split cathode (SC) are proposed. In the previous researches on SC, as a result space-charge-screening effect squeeze-state electrons accumulated nearby emission surface, diode current is limited, which finally results in low output power....

An X-band superradiant relativistic backward wave oscillator (SR-RBWO) using a structure combining resonant reflector and coupling gap is designed in this paper. This can realize the spatial mode from coaxial waveguide TEM to TM <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</inf> circular waveguide, output plate-insert TM01- TE xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> converter introduced. Finally, (SR) microwave directly with...

An improved L-band inverted relativistic magnetron powered by a virtual cathode is presented. extra emitter introduced at the end of slow-wave structure to reduce desired π mode start-oscillation time, which critical when short radiation pulses are required. Electrons produced both upstream and downstream emitters injected into interacting space simultaneously, rapid increase in electron density this region accelerates establishment cathode. Furthermore, additional provides more charged...