Relative permittivity characterization of foliages based on rectangular waveguide

Relative permittivity characterization of foliage is important in microwave system modeling and planning, especially in forest area. However, there is a difficulty in the characterization unless the foliage has to be formed so that its dimension is small enough compared to the measurement tool such as waveguide. This problem is encountered in the cavity perturbation method. Another method, for instance reflection/transmission, is suitable for this purpose however it is lack in accuracy. In order to overcome this problem, a simple method by combining the later using rectangular waveguide is proposed. The combination method is then examined for the characterization of relative permittivity of some foliage samples frequently found in Indonesia. Some analytical method based on waveguide theory is applied to verify the accuracy of the measurement result. The measurement shows different value for each kind of foliages that mostly is caused by different moisture content in each sample. Higher relative permittivity result means higher moisture contents of foliages. In despite of the proposed method shows its capability for the characterization of foliages, however some improvement in accuracy is needed in order to obtain the better characterization result.