The material properties of greatest importance in microwave processing of a dielectric are the complex relative permittivity ε = ε′ jε′′, and the loss tangent, tan δ = ε′′/ ε′. The real part of the permittivity, ε′, sometimes called the dielectric constant, mostly determines how much of the incident energy is reflected at the air-sample interface, and how much enters the sample. This paper show...

Atmospheric pressure plasma jets (APPJs) are being investigated in the context plasma medicine and biotechnology applications, and surface functionalization. The composition of the surface being treated ranges from plastics, liquids, and biological tissue, to metals. The dielectric constant of these materials ranges from as low as 1.5 for plastics to near 80 for liquids, and essentially infinit...

The dielectric spectroscopy of Anabaena 7120 protoplast suspensions has been investigated over the frequency range of 40 Hz-110 MHz. The protoplast suspensions showed a complicated dielectric dispersion consisting of at least four distinct sub-dispersions with the increasing frequencies due to the Maxwell-Wagner interfacial polarization. The double-shell model, in which an equivalent shell of t...

The method of images is most often employed in electrostatic examples with point or line charges in vacuum outside conducting planes, cylinders or spheres [1]. Develop similar prescriptions for the electric scalar potential in examples where the conductor is a linear, isotropic dielectric medium with relative permittivity . Discuss also media with relative permeability μ when a line current or ...

The Bergman–Milton bounds provide limits on the effective permittivity of a composite material comprising two isotropic dielectric materials. We demonstrate that the usefulness of these bounds is restricted to certain parameter ranges. Specifically, (a) for nondissipative materials the bounds may be unlimited if the constituent materials have relative permittivities of opposite signs; (b) for w...

The concept of nihility as an electromagnetic medium has emerged [1] from the rather extraordinary developments on negatively refracting materials during this decade [2, 3]. Whereas the relative permittivity and relative permeability of vacuum are ǫr = μr = 1, and those of anti– vacuum are ǫr = μr = −1, those of nihility are ǫr = μr = 0. The so–called perfect lens of Pendry [4] is made of anti–...

The method of images is most often employed in electrostatic examples with point or line charges in vacuum outside conducting planes, cylinders or spheres [1]. Develop similar prescriptions for the electric scalar potential in examples where the conductor is a linear, isotropic dielectric medium with relative permittivity . Discuss also media with relative permeability μ when a line current is ...

Effective complex permittivity measurements of materials are important in microwave engineering and microwave chemistry. Artificial neural network (ANN) computational module has been used in microwave technology and becomes a useful tool recently. A neural network can be trained to learn the behavior of an effective permittivity of material under microwave irradiation in a test system, and it c...

The electromagnetic properties of materials are defined from the two following constitutive parameters: permittivity, ε, and permeability, μ; ‘ε’ indicates how the medium reacts when an electric field is applied (field E of the electromagnetic wave), whereas μ indicates how the material behaves further to a magnetic excitation (field H of the electromagnetic wave). To take into account the loss...