Microwave absorption behaviour of novel rib cage structured piper betel leaves: Effect of drying and sintering processes

This paper focuses on a simple and cost-effective technique to explore the impact of the drying and sintering process on the microwave absorption behavior of piper betel leaves. The microwave absorption behavior of dried leaves and leaves sintered at 800 celcius for 3 h was examined. X -Ray Diffraction (XRD) study confirms the presence of elemental composites such as sucrose, cellulose, hemicellulose, and lignin in the dried sample, while sintered betel powder exhibited crystalline phases of CaSiO5, SiO2, Mg2P2O7, CaO, KPO3, Na2K(P3O9) K2CO3, and CaCO3. Microstructure study showed a unique rib cage and nanorod strand structure in the dried leaves and a porous structure in the sintered leaves. Spectroscopy analysis confirmed the occurrence of chemical composites in both dried and sintered betel leaves. The optical band gap of the sintered and dried leaves was 2.7 and 2 eV, respectively. Dielectric loss and loss mechanism in the betel leaf were studied using the DAK 3.5 kit. Results of the microwave absorption studies revealed that dried betel leaves with a thickness of 9 mm exhibited a high Reflection Loss (RLmax) of -22.69 dB at 11.37 GHz. Also, the same thickness has an effective absorption bandwidth (EAB) of 3.69 GHz, 87.8% of the X band frequency. On the other hand, sintered betel leaves with a thickness of 9 mm have a reflection loss (RLmax) of -48.57 dB at 10.52 GHz, with an effective absorption bandwidth (EAB) of 2.88 GHz, covering 68.5% of the X band frequency.