The concentration dependent properties of complex permittivity at 20 °C. (a) 13.56 MHz, (b) 2.45 GHz.
Complex permittivity of DI-water and NaCl solution at 20 °C (S = 35): (a) frequency dependent complex permittivity of NaCl solution; (b) complex permittivity of NaCl solution in the low frequency range 1–20 MHz; and (c) complex permittivity of NaCl solution in the microwave range 2–3 GHz.
Boundary conditions of electric fields. (a) for the perpendicular components, and for the parallel components. (b) A plane wave incident on the dielectric-dielectric interface boundary conditions have to be enforced.
The transmission coefficient of an EM wave incidenting on an air-dielectric interface. (a) 13.56 MHz; (b) 2.45 GHz.
Applicator used for food/material processing where two parallel plates are connected to a voltage source and a piece of material is placed in the air gap.
(a) Frequency dependent heating rate of NaCl solutions of different conductivity. (b) At different frequency, the concentration giving peak temperature rise is different. (c) Frequency-dependent peak ionic conductivity.
The dependence of the heating rate on the salinity and frequency in NaCl solution (incident electric field strength is 1 V/m).
The 13.56 MHz heating device (for illustration, the Petri dish and waveguide are not to scale). Reproduced by permission from Liu et al., Nanoscale 4, 3945–3953 (2012). Copyright 2012 by The Royal Society of Chemistry.
The field strength along the vertical central line of the microstrip waveguide. (a) The magnitude; (b) the phase.
Two dimensional field distribution in the Petri dish.
Comparison of simulation, theoretical calculation, and measurement of a bulk heating of NaCl solution at 13.56 MHz. Portion of the results (measurement and CST simulation) are reproduced by permission from Liu et al., Nanoscale 4, 3945–3953 (2012). Copyright 2012 by The Royal Society of Chemistry.
(a) Schematic diagram of the microwave heating setup; (b) transient temperature rise of DI-water and NaCl solution (power level 800 W and sample volume 50 ml).
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