Microwave dielectric heating was firstly reported on the use in organic chemistry by Gedye (Gedye, R. et al., 1986) and Giguere/Majetich (Giguere, R. J. et al., 1986) in the mid-1980s. However, it takes a long time before the wide application of this technology in the late 1980s and early 1990s. This has been principally attributed to the lack of controllability and reproducibility of the initi...

Temperature-dependent dielectric properties (dielectric constant and dielectric loss factor) and thermal properties (thermal conductivity and specific heat capacity) of whey protein gel and mashed potato were measured from -20°C to 100°C. A dielectric properties measurement system and a multipoint temperature calibration protocol were developed. The system consists of an impedance analyzer, a h...

A novel type of microwave probes based on the loaded aperture geometry has been proposed and experimentally evaluated for dielectrics characterization and high-resolution near field imaging. Experimental results demonstrate the possibility of very accurate microwave spectroscopic characterization of thin lossy dielectric samples and biological materials containing water. High resolution images ...

Commercial lead zirconate titanate (PZT) perovskite powders were used to fabricate ceramic tape and then sintered by microwave and conventional methods. Both dielectric and piezoelectric properties of PZT ceramic tapes were studied in terms of sintering process. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) show the PZT perovskite phase with smaller grain size and dens...

Microwave heating is a dielectric heating process, in which heat is generated via the interaction of dielectric materials with electromagnetic radiation. The dielectric constant is a measure of the material’s capacity to retard microwave energy as it passes through, while the loss factor is a measure of the material’s capacity to dissipate the energy. The materials with high loss factor are eas...

The emission from the vegetation canopy depends on the type of vegetation and the frequencies at which the emission is measured. For studying the vegetation canopy of a tree, the dielectric constant of its constituent is measured at microwave frequencies. In this study the dielectric constant is measured using waveguide cell method and its scattering coefficient is estimated using perturbation ...

Pumpable purees from purple-flesh sweetpotatoes (PFSP) were subjected to microwave heating using a 60 kW, 915 MHz continuous flow system, followed by aseptic packaging in flexible containers to obtain a shelf-stable product. Initial test runs were conducted using a 5 kW 915 MHz microwave system to measure dielectric in-line properties and examine the puree temperature profiles. The results demo...

We propose and characterize oil-in-gelatin dispersions that approximate the dispersive dielectric properties of a variety of human soft tissues over the microwave frequency range from 500 MHz to 20 GHz. Different tissues are mimicked by selection of an appropriate concentration of oil. The materials possess long-term stability and can be employed in heterogeneous configurations without change i...

Arrays of dielectric resonators—illuminated by an antenna—are used to ignite and sustain multiple microwave plasmas in parallel. Calcium titanate cylindrical resonators were arranged in a linear array with separation distances between 0.5 and 5 mm. The operating frequency was near the HEM111 resonance of 1.1 GHz. Paschen curves of the breakdown field and voltage in argon atmosphere are consiste...