Near-field microwave microscopy based on ferrite disk sensors with magnetostatic resonances

Abstract

Recently, using near-field scanning microwave microscopy (NSMM) is gaining popularity in many areas. However as of today in areas of medical diagnostics and nondestructive test it fails to meet the expectations. The conventional NSMM are measuring only by displacement of resonance frequency or by decrease of Q-factor which depends from dielectric and conductivity properties of materials. Because in such areas the relative permittivity practically is the same and as a result the contrast is too small for good detection what limit the performance of conventional NSMM performance. We propose a novel near-field microwave sensor with application to material characterization and biology. The sensor is based on a subwavelength ferrite-disk resonator with magnetostatic (MS) oscillations. Strong energy concentration and chiral properties of the near fields originated from the MS resonators allow effective measuring material parameters in microwaves, both for ordinary structures and objects with chiral properties. Recent experiments inspire optimism for further research, were shown the ability to determine properties of material not only by spectral displacement but also by refers to the differential absorption of left and right circularly polarized wave. The ability which itself is very important for effective sensing of biological material and living tissues.