Sol–gel synthesis of transition-metal doped ferrite compounds with potential flexible, dielectric and electromagnetic properties

A compact and flexible dielectric substrate with efficient electromagnetic performances both in flat and bending conditions are presented in this paper. The proposed substrates, for potential microwave radiator applications have been fabricated from Mn doped zinc ferrite compounds by sol–gel method. Prepared MnxZn(1−x)Fe2O4, (x = 0.0, 0.2, 0.4, 0.6, 0.8) substrates were analysed structurally by X-ray diffraction spectroscopy and morphologically studied by scanning electron microscopy. We studied the optical and dielectric properties in the microwave range to evaluate the new material as a dielectric substrate for microwave applications. The prepared flexible substrates exhibit high dielectric permittivity and low dielectric loss in the microwave frequency range. For the proof of concept, the electromagnetic performances both at flat and bending conditions were verified by loading an electromagnetic radiator. We report the detailed measured performances of the reflection coefficient below −10 dB, average efficiency above 73% and average realized gain above 1.5 dBi within the operational bandwidth for the first time. The measured stable omnidirectional radiation patterns both in flat and bending conditions also confirm the potential of the proposed material to be used as a new flexible dielectric substrate.