High-Frequency Noise Absorption of Ag–Fe3O4 Films on Microstrip Transmission Line

This paper proposes Ag-Fe₃O₄ films as a novel noise absorption material for the microstrip transmission line to replace current magnetic materials. The effect of the Ag-Fe₃O₄ films on a microstrip transmission line for high-frequency noise absorption is discussed. Ag-Fe₃O₄ films were prepared using the spin-coating technique and deposited on FR4 substrates. The film thickness was approximately 25-75 μm and sheet resistance was controlled in the range of 450-150 Ω. Crystal structures of Ag-Fe₃O₄ films were conducted using the X-ray diffraction technique. The radio frequency properties of these films were measured using an Agilent Technologies E8364A vector network analyzer in the frequency range of 1-20 GHz. The experimental results show that the composite sheet in the broadband frequency region effectively absorbs the electromagnetic noise, exhibiting a power loss greater than 70% in the frequency range of 6-20 GHz.