The 4 lowest Transverse-Electric modes of a cylindrical Dielectric Resonator Antenna were investigated using a commercially available simulation software. All 4 modes were shown to produce dipole or multi-pole radiation patterns, having Transverse-Electric polarization as opposed to Transverse-Magnetic as with conventional wire antennas. The even numbered modes were shown to be applicable to the niche application of small Unmanned Aerial Vehicles to ground station communications. A practical design for the lowest order even mode was prepared, and successfully demonstrated on a carbon fiber reinforced plastic ground plane. That design was then shown in simulation to have less adverse interaction when installed on a common small Unmanned Aerial Vehicle airframe at the new 5.05GHz telemetry band than an off-airframe dipole.

We propose a simple and small phase shifter for a beam-steerable base-station antenna. This phase shifter has no metallic heterojunction, and the phase shift is controlled by moving an M-shaped dielectric plate between the strip conductor and the ground plane of a strip line. We derive a design equation from the condition that at the center frequency f0, the reflection coefficient = 0. In this phase shifter, the reflection coefficient becomes minimum at f0 regardless of the movement distance, r, of the dielectric plate, and the relationship between the phase shift and r is linear. These characteristics are verified by performing simulations and measurements. The size of the M-shaped dielectric phase shifter is 0.27λ00.12λ0, where λ0 is the free-space wavelength at f0. The insertion loss is smaller than about 0.2 dB within a fractional bandwidth of 10%, and the phase shift can vary from 0 to about 80 degrees.

As means to control interface reactions between HfO2 and Ge(100), chemical vapor deposition (CVD) of ultrathin Ta-rich oxide using Tri (tert-butoxy) (tert-butylimido) tantalum (Ta-TTT) on chemically-cleaned Ge(100) has been conducted prior to atomic-layer controlled CVD of HfO2 using tetrakis (ethylmethylamino) hafnium (TEMA-Hf) and O3. The XPS analysis of chemical bonding features of the samples after the post deposition N2 annealing at 300 confirms the formation of TaGexOy and the suppression of the interfacial GeO2 layer growth. The energy band structure of HfO2/TaGexOy/Ge was determined by the combination of the energy bandgaps of HfO2 and TaGexOy measured from energy loss signals of O 1s photoelectrons and from optical absorption spectra and the valence band offsets at each interface measured from valence band spectra. From the capacitance-voltage (C-V) curves of Pt-gate MIS capacitors with different HfO2 thicknesses, the thickness reduction of TaGexOy with a relative dielectric constant of 9 is a key to obtain an equivalent SiO2 thickness (EOT) below 0.7 nm.

A gate-all-around tunneling field-effect transistor (GAA TFET) with local high-k gate-dielectric and tunneling-boost n-layer based on silicon is demonstrated by two dimensional (2D) device simulation. Application of local high-k gate-dielectric and n-layer leads to reduce the tunneling barrier width between source and intrinsic channel regions. Thus, it can boost the on-current (Ion) characteristics of TFETs. For optimal design of the proposed device, a tendency of device characteristics has been analyzed in terms of the high-k dielectric length (Lhigh-k) for the fixed n-layer length (Ln-layer). The simulation results have been analyzed in terms of on- and off-current (Ion and Ioff), subthreshold swing (SS), and RF performances.

In this paper, we have analyzed the guiding problem by dielectric waveguide with defects composed of dielectric circular cylinders array and deformed rhombic dielectric structure embedded in the middle layer and investigated the influence of energy flow for defect area by using the propagation constants at the guided area. From the numerical results, it is shown that we can obtain the confinement efficiency by rhombic dielectric structure compared with the deformed rhombic dielectric structure for both TE and TM modes.

Ultra wideband radar is one of the most promising techniques for non-invasive imaging in a dielectric medium, which is suitable for both medical screening and non-destructive testing applications. A novel imaging method for such an application is proposed in this brief paper, which has been extended from the advanced range points migration method to a multi-static observation model with circular arrays. One notable feature of this method is that it is applicable to either arbitrary dielectric or internal object shapes, and it can also expand the reconstructible image region compared with that obtained using the mono-static model by employing received signals after penetrating various propagation paths in dielectric medium. Numerical results for the investigation of an elliptical object, surrounded by a random dielectric surface, show the remarkable advantages of the proposed method with respect to image expansion.

We propose a new analytical method for a composite dielectric grating embedded with conducting strips using scattering factors in the shadow theory. The scattering factor in the shadow theory plays an important role instead of the conventional diffraction amplitude. By specifying the relation between scattering factors and spectral-domain Green's functions, we derive expressions of the Green's functions directly for unit surface electric and magnetic current densities, and apply the spectral Galerkin method to our formulation. From some numerical results, we show that the expressions of the Green's functions are valid, and analyze scattering characteristics by composite gratings.

In order to improve the detection performance in passive millimeter-wave (PMMW) imaging, a new method forwarding a null in the direction of human body and objects is proposed. The forward-nulling PMMW imaging using a dielectric tube occupied by cooling water placed near the focus line of a parabolic cylinder are performed. It is shown experimentally that the contrast between human body and conducting objects such as a conducting plate and a conducting sphere is improved by the presence of the cooling dielectric tube and parabolic cylinder.

A left-handed material with simple structure is proposed. The material is composed of periodic metal strips exhibiting both electric property and magnetic property. The dispersion relations and the transmission characteristics are confirmed experimentally. The main field pattern of guided mode in the material is similar to that of the plane wave, and a transmission characteristic with low reflection is obtained for an impedance matching region.

In the scattering problem of periodic gratings, at a low grazing limit of incidence, the incident plane wave is completely cancelled by the reflected wave, and the total wave field vanishes and physically becomes a dark shadow. This problem has received much interest recently. Nakayama et al. have proposed “the shadow theory”. The theory was first applied to the diffraction by perfectly conductive gratings as an example, where a new description and a physical mean at a low grazing limit of incidence for the gratings have been discussed. In this paper, the shadow theory is applied to the analyses of multilayered dielectric periodic gratings, and is shown to be valid on the basis of the behavior of electromagnetic waves through the matrix eigenvalue problem. Then, the representation of field distributions is demonstrated for the cases that the eigenvalues degenerate in the middle regions of multilayered gratings in addition to at a low grazing limit of incidence and some numerical examples are given.

The metallic waveguide is one of many effective media for millimeter- and submillimeter-waves because of the advantage of its low-loss nature. This paper describes the fabrication method of PTFE-filled waveguide components with the use of the SR (synchrotron radiation) direct etching process of PTFE, sputter deposition of metal, and electroplating. PTFE is known as a difficult material to process with high precision. However, it has been reported that PTFE microstructures can be fabricated by the direct exposure to SR. First, an iris-coupled waveguide BPF with 5-stage Chebyshev response is designed and fabricated for the Q-band. It is demonstrated that the present process is applicable for the fabrication of the practical components inclusive of narrow patterns. Then, a cruciform 3 dB coupler with air-filled posts is designed and fabricated for the Q-band. Directivity and matched state of the coupler can be realized by “holes” in the dielectric material. The measurement results are also shown.

The problem of a Gaussian beam that is incident on a plane dielectric interface from a denser dielectric medium to a rarer one and is reflected at the interface has been important research subjects studied by many researchers. In this paper, we have obtained a novel uniform asymptotic solution for reflection and beam shift of the Gaussian beam that is incident on the interface from the denser medium. The uniform asymptotic solution consists of the geometrically reflected beam, the lateral beam if any, and the newly derived transition beam which plays an important role in the transition region near the critical angle of the total reflection. We have confirmed the validity of the uniform asymptotic solution by comparing with the reference solution obtained numerically from the integral representation. We have shown that, in addition to the Goos-Hanchen shift and the angular shift, the Gaussian beam is shifted to either direction by the interference of the geometrically reflected beam and the lateral beam near the critical angle of the total reflection.

A 100 GHz grooved circular empty cavity is proposed for the low loss dielectric substrate measurements by the cut-off circular waveguide method in W band. The influence of the excitation holes for the coaxial cable with a small loop are revealed by an FEM based 3D electromagnetic simulator. And also, the diameter of the excitation hole is determined based on the calculated results and the manufacturing accuracy. Then, two kinds of four 100 GHz grooved circular empty cavities are fabricated. Comparative experiments of the cavities with the different excitation holes validate the simulated results. Moreover, the complex permittivity of a PTFE plate is measured using the fabricated four cavities by the cut-off circular waveguide method around 84 GHz. The measured results agree within measurement error about 0.5% for εr and 5% for tanδ. Also, these results accord with results measured by the Whispering-Gallery mode resonator method in 85–110 GHz band. It verifies that the proposed 100 GHz cavity for the cut-off waveguide method is useful for the complex permittivity measurement of low loss dielectric substrates in W band.

As the integration density and capacitance of semiconductor devices have increased, high-dielectric (High-k) materials have attracted considerable attention. We investigated the dependence of threshold voltage (Vth) characteristics of the High-k/Metal Gate MOSFET fabricated with 65 nm CMOS process on the temperature, in comparison to conventional SiON/Poly-Si Gate MOSFET. Two aspects including the Fermi level and the channel mobility in MOSFET are discussed in details. Furthermore, the influence of threshold voltage characteristics of the High-k/Metal Gate MOSFET on the logic threshold voltage (Vth-inv) of CMOS inverter is reported in this paper.

A stacked structure consisting of ∼ 1 nm-thick MgO and ∼ 4 nm-thick HfO2 was formed on thermally grown SiO2/Si(100) by MOCVD using dipivaloymethanato (DPM) precursors, and the influences of N2 anneal on interfacial reaction and defect state density in this stacked structure were examined. The chemical bonding features of Mg atom were evaluated by using an Auger parameter independently of positive charge-up during XPS measurements. With Mg incorporation into HfO2, a slight decrease in the oxidation number of Mg was detectable. The result suggests that Mg atoms are incorporated preferentially near oxygen vacancies in the HfO2, which can be responsible for a reduction of the flat band voltage shifts observed from C-V characteristics.

A dominant-mode rectangular cavity antenna design yielding an improved bandwidth is experimentally verified. Simple field theories indicate that extending the aperture height should increase the antenna bandwidth without shifting the operation frequency. Antenna samples built from a 4.4 dielectric constant material produce 3-dB efficiency bandwidths of 15 and 23 percent for the respective cavity height-to-width ratios of 0.5 and 0.75 at 7 GHz.

We have demonstrated the inverter operation of stacked-structure CMOS devices using pentacene and ZnO as active layers. The fabrication process of the device is as follows: A top-gate-type ZnO thin-film transistor (TFT), working as an n-channel transistor, was formed on a glass substrate. Then, a bottom-gate-type pentacene TFT, as a p-channel transistor, was fabricated on top of the ZnO TFT while sharing a common gate electrode. For both TFTs, solution-processed silicone-resin layers were used as gate dielectrics. The stacked-structure CMOS has several advantages, for example, easy patterning of active material, compact device area per stage and short interconnection length, as compared with the planar configuration in a conventional CMOS circuit.

An algorithm is formulated for reconstructing a dielectric cylinder with the use of the T-matrix and the singular value decomposition (SVD) and is discussed through numerical examples under noisy conditions. The algorithm consists of two stages. At the first stage the measured data of scattered waves is transformed into the T-matrix. At the second stage we reconstruct the cylinder from the T-matrix. The singular value decomposition is applied in order to separate the radiating and the nonradiating currents, and the radiating current is directly obtained from the T-matrix. The nonradiating current and the object are reconstructed by decreasing a residual error of the current in the least square approximation, where linear equations are solved repeatedly. Some techniques are used in order to reduce the calculation time and to reduce the effects of noise. Numerical examples show us that the presented approach is simple and numerically feasible, and enables us to reconstruct a large object in a short time.

This paper attempts to analyze theoretically the propagation characteristics in the transverse section of upper body to support on-body wireless communications. The analytical estimation assumes that the human body is structured as a lossy-dielectric circular cylinder with infinite length that consists of the 2/3-muscle equivalent uniform tissue. Each scattering electric field formulation inside and outside of the cylinder is derived for scattering characteristics in the propagation environment including the human body when the source current has the vertical direction to the cylinder surface or the horizontal direction to the cylinder axis. In order to confirm the reliability of the formulation, total electric field distributions at 2.45 GHz are compared with the results by the finite-difference time-domain (FDTD) method. In each current direction, general scattering characteristics and the influence on the total propagation are estimated. Furthermore, from scattering and total electric field intensities evaluated with the variations of operating frequency, radius of the human body, and distance between a source and the human body, propagation characteristics are investigated to assist in the design of a device for on-body propagation channel with the upper body.

Ba0.5Sr0.5Ta2O6 (BSTA) thin film was successfully fabricated on a Pt/SiO2/TiO2/Si substrate using the Sol-Gel method. Fundamental electrical properties of the BSTA thin film were investigated using metal-insulator-metal (MIM) structure. No diffusion of ions, from the thin film or the substrate, is observed because of the using of MIM structure. The Root Mean Square roughness of 1.04 nm shows that thin film grew well on the substrate. The BSTA thin film shows a much higher dielectric constant of about 130 than conventional gate insulators and high-k materials that are currently used in Thin Film Transistors. Low leakage current density of about 10-8 A/cm2 was obtained at an applied electric field of 500 kV/cm. Schottky emission is the dominant conduction mechanism at applied electric fields lower than 500 kV/cm and Fowler-Nordheim tunneling is the dominant conduction mechanism at higher applied electric fields. The Schottky barrier height between the Pt electrode and the Ba0.5Sr0.5Ta2O6 thin film was estimated to be 0.75 eV.