Compact Cascaded Broadband Choke Device for Suppressing Transmission Shaft Microwave Leakage

The advancement of mechatronics has increased the use of transmission shafts in microwave systems. To prevent microwave leakage caused by the gap around the transmission shaft from affecting system operation, this letter proposes a novel compact cascaded broadband choke device (CBCD). The CBCD employs a cascaded multilayer choke structure, enabling it to achieve broadband performance and higher suppression of microwave leakage. In addition, the CBCD is designed to be compact by optimizing the cascade structure and using high-dielectric-constant materials for miniaturization. For demonstration, a double-layer CBCD centered at 10 GHz is designed and fabricated. The simulation and experimental results show that the double-layer CBCD improves the microwave leakage suppression by 30 dB over a relative bandwidth of 4% compared to the case without it. In addition, the relative bandwidth and suppression can be further improved by increasing the number of layers in the CBCD.