Optical, Dielectric, and Electromagnetic Microwave Absorption Properties of Hexagonal Ba3(VO4)2

In this work, we used a simple sol-gel synthesis technique to prepare hexagonal Ba 3 (VO 4 ) 2 . X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopy were performed, confirming that Ba 3 (VO 4 ) 2 has a hexagonal structure. To investigate the influence of interfacial interactions at grain boundaries on microwave absorption, AFM studies were performed. UV–vis studies show the direct and indirect optical energy band gaps of Ba 3 (VO 4 ) 2 were determined as 3.81 eV and 3.25 eV, respectively. The dielectric studies reveal that the dielectric constant ( ε ׳) of Ba 3 (VO 4 ) 2 ranges from 1.55 to 6.02 in the frequency range of 2–20 GHz, with an average ε ׳ value of 3.84. The microwave absorption properties of Ba 3 (VO 4 ) 2 were evaluated in the frequency range of 8–18 GHz, covering the X and Ku bands at different thicknesses from 4.5 mm to 8 mm. The highest effective absorption bandwidth (EAB) of 4.44 GHz was observed within the frequency range of 12.83–17.27 GHz, with a maximum reflection loss of −71.43 dB at a resonance frequency of 15.05 GHz. Additionally, at a thickness of 7.5 mm, Ba 3 (VO 4 ) 2 achieved a maximum reflection loss of −75.22 dB at 10.03 GHz, with an EAB of 2.94 GHz (covering the X band from 8.57 GHz to 11.51 GHz).