Radically different effects on materials by separated microwave electric and magnetic fields

Abstract

Using a 2.45 GHz wave-guided cavity, in a single mode TE₁₀₃ excitation, we were able to physically locate compacted 5 mm pellets of samples separately at the H (magnetic) node (where the E field is nearly zero), or the E (electric) node (where H field is nearly zero). A preliminary survey of a variety of metals, (Cu, Fe, Co..) ceramics (ZnO, etc.), and composites, (WC-Co, ZnO-Co) showed remarkable differences in their heating behaviors. The results establish conclusively that the magnetic field interaction contributes greatly to microwave heating of common materials in a manner, previously neglected in most theories of microwave heating, albeit still to be understood.

Keywords:

• Microwaves
• E-field
• H-field
• ZnO
• WC