Studies on microwave perturbation and permittivity of leaf stem material

Pradeep Kamble, Vijaya Puri

Abstract

Wave guide reflectometer and voltage standing wave ratio (VSWR) methods have been used to study the X band (8- 12 GHz) microwave perturbation and permittivity of leaf stem material of Ficus Bengalanesis. The effect of moisture content has been investigated on the stem taken from two places in the branch. The transmittance of the waveguide decreases and reflectance increases due to the stem. The perturbations in the reflection mode are highly frequency dependent. The real permittivity ε’ of the stem has a value of ~ 80 and ε” is ~ 180 at ~ 10 GHz. Beyond 10 GHz the dielectric constant shows frequency dependent variations. The permittivity decreases with decrease in moisture content in the stem. The microwave impedance shows both capacitive and inductive reactance varying randomly with frequency and moisture content.