College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, People's Republic of China.
Rev Sci Instrum. 2023 Jan 1;94(1):014713. doi: 10.1063/5.0130103.
To realize online measurement of power, frequency, and phase for a modularized relativistic triaxial klystron amplifier in a narrow space, a compact directional coupler with high directivity, high power handling capacity, and large bandwidth has been investigated numerically and experimentally. The method with coupling holes distributed in both the longitudinal and lateral directions is proposed, and the simulation results indicate that when two holes are employed, directivity larger than 20 dB is achieved over a 300 MHz bandwidth in the X-band and the maximal electric field strength is controlled to be 198.5 kV/cm with 1 GW power injection, while the whole coupler longitude is optimized to be as short as 50 mm. High power experiments have been performed with a 10 GHz relativistic triaxial klystron amplifier, and the results show that the measured power, frequency, and phase shift of the directional coupler have good agreement with the results obtained in the far-field.
为了在狭小空间内实现模块化相对论三轴速调管放大器的功率、频率和相位的在线测量，研究了一种具有高方向性、高功率处理能力和大带宽的紧凑型定向耦合器。提出了在纵向和横向都分布耦合孔的方法，仿真结果表明，当采用两个孔时，在 X 波段 300MHz 的带宽内可以实现大于 20dB 的方向性，在注入 1GW 功率时最大电场强度被控制在 198.5kV/cm，而整个耦合器的长度被优化到 50mm 以内。采用 10GHz 相对论三轴速调管放大器进行了高功率实验，结果表明，定向耦合器的测量功率、频率和相移与远场测量结果吻合较好。
