Magnetic MEMS reconfigurable frequency-selective surfaces

A reconfigurable frequency-selective electromagnetic filter implemented by integrating hard magnetic materials with microelectromechanical systems (MEMS) provides a new variation of reconfigurable frequency-selective surfaces (FSS). By incorporating magnetically actuated dipole elements that are capable of being tilted away from the supporting surface, we can tune the FSSs operating frequency without having to physically alter the dimensions of the dipole elements. The 25×25 array of microactuators used in this work each consist of a 896×168×30 μm³ ferromagnetic plate made of 40Co-60Ni, layered with a 1-μm-thick conductor (Au), attached to a pair of 400×10×1 μm³ polysilicon torsion beams, suspended just above the supporting substrate. The high remanent magnetization of the ferromagnetic material allows for relatively small magnetic fields (∼2.1 kA/m) to induce significant angular deflections (∼45°). This innovative reconfigurable FSS design has successfully demonstrated electromagnetic-signal diplexing and tuning its resonant frequency over a bandwidth of 2.7 GHz at a frequency of 85 GHz.