Nanomagnetic films and arrays for nonlinear devices in highly-integrated RF modules

Magnetic materials have traditionally faced several limitations for RF and power applications because of their unstable permeability with frequency and electric field. However, the same attributes of these materials, when designed at nanoscale, enable interesting nonlinear properties for applications as frequency-selective limiters and signal-to-noise enhancers. Anisotropic nanostructures also enhance frequency stability. This paper explores nanomagnetic arrays for such ultra-miniaturized RF components in multimode and multiband (MMMB) RF modules. Permalloy films and nanodot arrays were modeled for their frequency-response to assess their nonlinear properties. By designing the dimensions at nanoscale, field-dependent permeability spectra were obtained using micromagnetic simulations. Permalloy thinfilm and nanodot arrays were fabricated on silicon substrates using e-beam evaporation and e-beam nanolithography. The simulation results for blanket films were validated by characterizing the permeability spectra using strip-line structures. Results indicate that nanomagnetic films and arrays can be used to create nonlinear devices as building blocks for a variety of highly-integrated RF modules.