A novel preliminary study on microwave characterization of Siamese Mangoes ripeness at K-Band

This project presents a microwave non-destructive testing (MNDT) method to determine the ripeness of Siamese mangoes at a frequency range of 18 to 26.5 GHz (K-Band) using free space microwave measurement (FSMM) system. The basic components of the FSMM system are spot focusing horn lens antennas, a vector network analyzer (VNA) and a computer. In this method, the free space reflection, S₁₁ and transmission, S₂₁ coefficients are measured for the samples sandwiched between two Teflon plates that are quarter wavelengths at mid-band. The thru, reflect and line (TRL) calibration technique is used to eliminate the effect of undesirable multiple reflections. The extracted S₁₁ and S₂₁ are keyed in a developed algorithm to calculate the complex permittivity of moisture contents within the samples. Results have shown that the dielectric constants for ripe and unripe mangoes are between 26.3 to 29.5 and 26.1 to 29.2 respectively. Other parameters including loss factor and loss tangent are also discussed.