A cascaded broadband choke device for the transmission shaft in the waveguide

In this paper, a cascaded broadband choke device is presented, which can prevent microwave leakage by a transmission shaft in the waveguide. Utilizing the principle of impedance transformation, the bandwidth attributes of the cascaded broadband choke device are examined. It is discerned that augmenting the quantity of dielectric slices can enhance the bandwidth of the choke device. Furthermore, based on the principle of equivalent wavelength, escalating the dielectric constant of the dielectric slice can effectively reduce the choke device’s volume. An electromagnetic simulation software is employed to establish a model of a double-layer choke structure. This model is then used to simulate and analyze the impact of variables such as the number of dielectric slices, dielectric constant, and size on the choke structure’s performance. The simulation outcomes indicate that at a working frequency of 10 GHz, the leakage loss of the double-layer choke structure is less than −40 dB within a bandwidth range of 9.70 GHz-10.82 GHz, achieving a relative bandwidth of 8.2%. A simplified simulation model is subsequently utilized for physical fabrication and testing. The experimental findings not only corroborate the accuracy of the simulation results but also affirm the low-loss and wide-bandwidth characteristics of the proposed choke structure.