Gyro-magnetically Induced Transparency and Opaqueness at Microwave Frequency

Hsien Wen Chao^1*, Wen Ju Lai¹, Tsun Hsu Chang¹

¹物理系, 國立清華大學, 新竹市, Taiwan

* Presenter:Hsien Wen Chao, email:s9822817@m98.nthu.edu.tw

The permeability of ferrite is a second rank tensor, depending on the saturation magnetization, the dc bias magnetic field, and the operating frequency. By adjusting the applied bias magnetic field, the permeability tensor can be manipulated, which may change the propagating properties of the wave. Here we proposed a coaxial structure with a toroidal ferrite. At a frequency of 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. From the transparent state to the opaque state, the variation of the bias magnetic field was just 62 gauss in the experiment. It facilitated a high-speed, high-power, and quality switch. The derivate equations explain the underlying physics, which provides a solid ground for designing similar switches at other frequency bands.

Keywords: Ferrite switch, permeability, gyro-magnetically induced transparency, microwave