Magnetically tunable acoustic add-drop filter via Terfenol-D

This article introduces a new approach to provide a magnetically tunable add-drop filter structure based on a solid-solid phononic crystal by varying the magnetic field intensities of Terfenol-D in the GHz frequency range. The filter system is prepared with a two-dimensional phononic crystal composed of Nylon as the base material, connected with a square array of circular Molybdenum cylinders. The plan includes a bus waveguide connected to a single-ring resonator and a drop waveguide. The ring resonator embraces six embedded Terfenol-D cylinders that control their Young's modulus values, and strategically they are placed on both sides of the ring resonator. This tunable add-drop filter is designed to be manipulated by an outside magnetic field, capitalizing on the changes in Young's modulus in magnetostrictive materials in response to different magnetic field intensities. The tunability of the proposed elastic filter output is achieved through dynamic control of Young's modulus. The resonance frequency of the ring resonator and dynamic control of these Terfenol-D cylinders within it are critical to the filter's performance. The filter acts based on resonance frequencies particular to Young's modulus of Terfenol-D within the ring resonator, utilizing a new method that manipulates the interposition of acoustic waves using an external magnetic field in a tunable add-drop filter configuration. Furthermore, the efficiency of the proposed filter has been endorsed through the coupled mode theory. Additionally, the filter demonstrates suitable performance with a notable average quality factor of 10502, minimal average insertion loss of 1.5 dB, and average damping ratio of 4.5 x 10-5. This suggested filter is straightforward and suitable for acoustic communication systems and networks.