Performance of high temperature open-ended coaxial probe for dielectric properties of high loss food materials in frequency range 10-200 MHz

Abstract

Agilent high temperature open-ended coaxial probe (HTOCP) and DAK-12 open-ended coaxial
probe (DOCP) are recommended in conjunction with vector network analyzer (VNA) to measure the
dielectric properties in frequency 200 MHz-20 GHz, 10 MHz-3 GHz and temperature range -40 to
+200?, 0 to 60? respectively. In literature, HTOCP has been used from 10/20 MHz-20 GHz for
food materials as 10-200 MHz frequency range covers 3 ISM radio wave frequencies 13 MHz, 27
MHz, 40 MHz. However, any comparison or deviation from standard is not considered in 10-200
MHz range. Therefore, dielectric data of wheat dough and pasteurized milk obtained at 30 and 50?
with HTOCP in frequency range 10-200 MHz was compared with that of DOCP. The compared
results indicate that HTOCP has performed satisfactorily in frequency range 15-200 MHz to measure
the dielectric properties of milk and dough at 30 and 50? within allowed deviations of 5%.
However, deviations for dielectric loss factor of dough at 30? increase from 5% to 12% as
frequency decreases from 200 MHz to 10 MHz