摘要
The ferrite's permeability is a second-rank tensor, depending on the saturation magnetization, the dc bias magnetic field, and the operating frequency. The permeability tensor can be manipulated by adjusting the applied bias magnetic field, changing the wave's propagating properties. Here we proposed a coaxial structure with a toroidal ferrite. At frequencies around 2.45 GHz, the incident wave can transmit or reflect by merely adjusting the bias magnetic field. The coaxial-ferrite structure can serve as a switch. The variation of 62 Oe of the bias magnetic field in the experiment changed the device's state from transparent to opaque. The derived equations explain the underlying physics, which provides a solid ground for designing similar switches at other frequency bands.