Design and optimization of G-band extended interaction klystron with high output power

Abstract

A ladder-type Extended Interaction Klystron (EIK) with unequal-length slots in the G-band is proposed and designed. The key parameters of resonance cavities working in the π mode are obtained based on the theoretical analysis and 3D simulation. The influence of the device fabrication tolerance on the high-frequency performance is analyzed in detail, and it is found that at least 5 μm of machining precision is required. Thus, the dynamic tuning is required to compensate for the frequency shift and increase the bandwidth. The input and output coupling hole dimensions are carefully designed to achieve high output power along with a broad bandwidth. The effect of surface roughness of the metallic material on the output power has been investigated, and it is proposed that lower surface roughness leads to higher output power. The focusing magnetic field is also optimized to 0.75 T in order to maintain the beam transportation and achieve high output power. With 16.5 kV operating voltage and 0.30 A beam current, the output power of 360 W, the efficiency of 7.27%, the gain of 38.6 dB, and the 3 dB bandwidth of 500 MHz are predicted. The output properties of the EIK show great stability with the effective suppression of oscillation and mode competition. Moreover, small-signal theory analysis and 1D code AJDISK calculations are carried out to verify the results of 3D PIC simulations. A close agreement among the three methods proves the relative validity and the reliability of the designed EIK. Thus, it is indicated that the EIK with unequal-length slots has potential for power improvement and bandwidth extension.

The Research Advance on Planar Multibeam Extended Interaction Circuit

“…Recently, Li et al have studied G-band high power extended interaction klystron technology systematically [25]. A G-band ladder extended interaction klystron with unequal slots was designed.…”

Design of the Radio Frequency Section of a Ka-Band Multiple Beam Ladder-Type Extended Interaction Klystron

“…Moreover, proper coupling irises (or loops) are required for input and output cavities so that the device will have good matching at the input to the RF driver to the load at the output port. The analytical approach [24,25,27,34,35] used for designing for expression required to design the RF section is presented in the following section. Ladder-shaped resonant cavities have been considered for larger shunt impedances (with extended interaction configuration), and multiple numbers of beams have been considered for low operating voltage (and individual beamlet current) and microfabrication and 3D fabrication compatibility.…”

“…The applications of such devices include particle accelerators, industrial and plasma heating, RADARs and active denial technologies, deep space communication, etc. [24][25][26][27][28]. A number of amplifiers and oscillators operating in the Ka-Band and other higher-frequency bands employing multiple beams and extended interaction structures are being explored globally [19,[29][30][31][32][33].…”

A G-Band High Output Power and Wide Bandwidth Sheet Beam Extended Interaction Klystron Design Operating at TM31 with 2π Mode

“…Aside from that, it could further improve the power and expand the bandwidth. Thus, our EIK with high-order mode is a good choice for high-power terahertz radiation sources [24].…”