Faraday Optical Isolator/Gyrator Design in Planar Dielectric Waveguide Form

The possibilities of using the magnetic Faraday effect to provide a planar dielectric waveguide isolator or circulator are studied. At least two active elements which couple the TE and TM waveguide modes are required. One of these is magnetooptic. Preliminary design data for a dielectric waveguide isolator in which the mode-converting media forms the substrate and top layer of a single waveguide structure are reported. This design should prove more practical than the optical tandem structures proposed previously.     

Radiation characteristics of a source in a thin substrate mountedover a dielectric medium

The radiation pattern of a line source is calculated for the case in which the source is lying on the top or the bottom surface of a lossless dielectric substrate that is mounted on the top of semi-infinite dielectric medium. It is found that in both cases the pattern along the interfaces has a null; that the pattern in the upper semi-infinite medium has a single lobe; and that the pattern in the lower semi-infinite medium has many lobes, the number of which varies with the substrate thickness. In both cases, the power radiated into the lower medium is more than that radiated into the upper medium. Applications of this calculation to remote sensing, microstrip antenna technology, and antenna arrays are discussed     

Asymmetric bow-tie antenna for GSM/CDMA and 3G/WLAN

A bow-tie antenna with asymmetrical and overlapped arms printed on the top and bottom of a dielectric substrate is proposed and tested. By adjusting the asymmetry and overlapping of the two arms, return loss below -10 dB, quasi-omnidirectional radiation characteristics, reasonable gain values and beam tilt can be achieved at GSM/CDMA and 3G/WLAN bands.     

Radiation and scattering from infinite periodic printed antennaswith inhomogeneous media

The hybrid method of moments (MoM)/Green's function method technique is applied to infinite periodic printed antenna arrays containing dielectric inhomogeneities. The solution uses an integral equation for an infinite periodic printed array on or over a homogeneous dielectric substrate, coupled with equivalent volume polarization currents for dielectric inhomogeneities on top of the homogeneous substrate. Volume pulse-basis functions were used to expand the volume polarization currents. A hybrid MoM/Green's function method solution was then obtained through the matrix form of the problem. The two-dimensional (2-D) solution of plane wave scattering from a grounded dielectric slab was used to validate the reaction impedance of the dielectric inhomogeneity. Several infinite periodic printed dipole arrays with dielectric supports and overlays were studied with this solution and good agreement was observed between the hybrid MoM/Green's function method and waveguide simulator experiments     

A new SOI high voltage device based on E-SIMOX substrate

A new NI (n+ charge islands) high voltage device structure based on E-SIMOX (epitaxy-the separation by implantation of oxygen) substrate is proposed. It is characterized by equidistant high concentration n+-regions on the top interface of the dielectric buried layer. Inversion holes caused by the vertical electric field (Ev) are located in the spacing of two neighboring n+-regions on the interface by the force from lateral electric field (EL) and the compositive operation of Coulomb's forces with the ionized donors in the undepleted n+-regions. This effectively enhances the electric field of dielectric buried layer (EI) and increases breakdown voltage (Vb). An analytical model of the vertical interface electric field for the NI SOI is presented, and the analytical results are in good agreement with the 2D simulative results. EI = 568 V/μm and VB = 230 V of NI SOI are obtained by 2D simulation on a 0.375-μm-thick dielectric layer and 2-μm-thick top silicon layer. The device can be manufactured by using the standard CMOS process with addition of a mask for implanting arsenic to form NI. 2-μm silicon layer can be achieved by using epitaxy SIMOX technology (E-SIMOX).     

Experimental verification of the reduction of coupling between dipole antennas by using a woodpile substrate

In this paper, the mutual coupling between dipole antennas placed on top of a woodpile structure is experimentally investigated. The coupling between dipoles backed by a woodpile substrate is compared with that obtained when the dipole antennas are placed on a dielectric substrate and when they radiate into free space. On average, between 2 and 7 dB reduction of the mutual coupling is achieved with respect to the dielectric substrate case when the woodpile substrate is used. The free space coupling is also reduced in the H-plane configuration case. However, the E-plane coupling slightly increases due to modification of the radiation pattern. Imaging array applications could potentially benefit from the use of EBG substrates due to the improved isolation between pixels.     

A nanoanalytical investigation of the Ga2O3/GaGdO dielectric gate stack for InGaAs based MOSFET devices

In this paper, a subnanometer characterization of the Ga₂O₃/GdGaO dielectric gate stack grown on top of InGaAs lattice matched to n⁺ InP substrate is presented. The paper shows the analysis of two samples grown using different substrate temperature. This clearly affects the electrical characteristics as well as the photoluminescence properties. The paper also describes how the growth conditions of oxide stack affect the elemental distribution across the interface region.     

A numerical study of a dielectric disk antenna above groundeddielectric substrate

An antenna made of a dielectric disk with a high permittivity mounted on top of a grounded dielectric substrate of low permittivity is analyzed. A numerical procedure based on surface integral equations, derived from the equivalence principle, is used to compute the natural resonant frequencies for the HEM₁₁ mode from which the radiation Q factor of the antenna is obtained. Then the radiation pattern of the antenna, operating at the resonant frequency evaluated previously, is computed with an electric dipole excitation located within the dielectric substrate under the dielectric disk. The effect of various parameters on the radiation characteristics of the antenna is studied, and presented in the form of diagrams. The low values of the radiation Q, combined with the high values of the dielectric Q and conductor Q, indicate that this antenna promises to be more efficient then the microstrip antenna     

Influence of dielectric loading on PIFA antennas in close proximity to user's body

The emerging trend for handset antenna design puts strong constraints on their volume occupation and user?s proximity resilience. Several PIFA antenna configurations are investigated, studying the influence of substrate/superstrate dielectric loading on both absorption and mismatch loss at 900 MHz. By using high-permittivity materials and by leaving a small clearance area between the PIFA top plate and the back of the handset, both absorption and mismatch loss can be reduced at the expense of a narrower bandwidth.     

The mutual influence of surface energy and substrate temperature on the saturation mobility in organic semiconductors

We report on a mutual correlation between the substrate temperature during semiconductor deposition and the surface energy of the gate dielectric on the charge carrier mobility in bottom gate top contact organic field effect transistors (OFETs) with N,N′-diphenyl-3,4,9,10-perylene tetracarboxylic diimide (DP-PDI) as organic semiconductor.     

Dielectric reflector backed aperture-coupled antennas for reduced back radiation

A new design using a dielectric reflector to reduce the back radiation of aperture coupled antennas is proposed and developed in this paper. To validate the proposed design, a concise theory analysis is first conducted and then the proposed design is analyzed in a modified aperture coupled microstrip antenna. In this design, a radiating patch and a microstrip feed line are both etched on the same side of a top substrate and a coupled slot is etched on the opposite side of this substrate. To examine the effect of the dielectric reflector on the antenna performance, theoretical simulations and experimental investigations were carried out, and a good agreement between the theoretical expectation and the measured results validates the proposed design. The measured radiation patterns show that the proposed structure can offer a high radiation efficiency, a high front to back radiation ratio, and a high co-cross polarization ratio. With these features, the proposed design is significant in the electromagnetic interference and electromagnetic compatibility (EMI/EMC) designs for reduced undesirable radiation.     

Inkjet printed dielectrics for electronic packaging of chip embedding modules

The inkjet printing of a dielectric layer as part of an assembling process for a semiconductor device was evaluated. This layer embeds a chip so that a space-saving package with surface conformal conductive paths instead of wire bonds can be designed. Three different polymer solutions were tested whereas the polyimide ink is favored due to the high thermal stability and dielectric strength of the printed layer. By multiple printing of dielectric layers on top of each other a sufficient layer thickness and cover of the chip edges as well as accurate contact holes can be realized.     

A tapped-delay-line superconductive chirp filter in shieldedmicrostrip

A superconducting chirp filter having a dispersive time delay of 26 ns and a 3.4-GHz bandwidth centered at 4.7 GHz has been fabricated using a niobium-on-silicon shielded microstrip technology. Along a 2×1.6 m delay are, unequally spaced microstrip directional couplers ire employed as sampling devices. To achieve an improvement in dispersion and coupler directivity over conventional microstrip, the device uses a superconductive shield mounted at a distance equal to the height of the dielectric on top of the microstrip structure. Structural support of the 70-μm-thin high-resistivity dielectric is provided by a large-area bond to a glass substrate     

Sub-mA threshold 1.5-/spl mu/m VCSELs with epitaxial and dielectric DBR mirrors

In this letter, we report low threshold 1.5-/spl mu/m vertical-cavity surface-emitting lasers with epitaxial and dielectric distributed Bragg reflector (DBRs). The device consists of a lattice-matched InAlAs-InAlGaAs DBR grown on an InP substrate, an InAlGaAs quantum well active region, a metamorphic GaAs tunnel junction, and a SiO/sub 2/-TiO/sub 2/ dielectric DBR. The current confinement is achieved by oxidizing an AlAs metamorphic layer grown on top of the active region. Small aperture devices show a minimum threshold of 0.8 mA at room temperature in continuous-wave operation.     

Fabrication of low-stress dielectric thin-film for microsensorapplications

A method of fabricating low-stress dielectric thin film as the supporting material of micromachined devices is reported. The film is processed by post thermal oxidation of silicon-rich nitride (SN) deposited on a silicon substrate by LPCVD. Due to the compensation on the nitride by its top oxide, an ultra-low residual stress less than 10 MPa can be obtained with a proper oxidation scheme. Characteristics of the oxidized nitride were analyzed by Auger electron spectroscopy (AES) and ellipsometry. Large floating membranes of 4×4 cm² and 400-nm thick can be made by this method with TMAH etching     

Thermal Stability Improvement of Vertical Conducting Green Resonant-Cavity Light-Emitting Diodes on Copper Substrates

Green light vertical-conducting resonant-cavity light-emitting diodes (RCLEDs) have been fabricated on a Cu substrate by the combination of laser lift-off and plating techniques. The structure of the RCLED/Cu is consisted of the InGaN-GaN multiple-quantum-well active layer between three layers of the dielectric TiO-SiO distributed Bragg reflector as a top mirror and an Al metal layer as a bottom mirror. It was found that the RCLED with Cu substrate presents superior thermal dissipation and a stable electroluminescence emission peak wavelength (507 nm) under a high injection current. It is attributed to the Cu substrate providing a good heat sink and effectively reducing the junction temperature.     

GIBC formulation for the resonant frequencies and fielddistribution of a substrate-mounted dielectric resonator

Dielectric resonators (DR's) are widely used in telecommunication systems. A method is proposed here to find the resonant frequency and field distribution in a substrate-mounted DR structure. The field of a dielectric rod has been decomposed into a combination of guided modes with unknown coefficients and an unknown continuous spectrum of radiation field. The unknowns are then obtained by applying two generalized impedance boundary conditions (GIBC's) representing the substrate and air layers at the top and bottom of the DR. This leads to the calculation of the total (guided+radiation) field as well as the resonant frequency of the structure     

一种新的基于E-SIMOX衬底的PSOI高压器件

首次提出了一种新的采用E-SIMOX技术的界面电荷岛结构的PSOI高压器件(NI PSOI)。该结构在SOI器件介质层上界面注入形成一系列等距的高浓度N+区。器件外加高压时,纵向电场所形成的反型电荷将被未耗尽N+区内高浓度的电离施主束缚在介质层上界面,同时在下界面积累感应电子。详细研究NI PSOI工作机理及相关结构参数对BV的影响,在0.375μm介质层、2μm顶层硅上仿真获得188 V高耐压,较常规结构提高54.1%,其中附加场EI和ES分别达到190 V/μm和13.7 V/μm。     

A Parallel-Plate Waveguide Approach to Microminiaturized, Planar Transmission Lines for Integrated Circuits

The parallel-plate waveguide with a two-layer loading medium, a conducting semiconductor substrate, and a relatively thin dielectric layer approximates the interconnections in many integrated systems if the fringing fields are ignored. The fundamental mode of this structure is an E mode which is a surface wave. Its propagation behavior is analyzed in this paper and the equations are evaluated by highly accurate numerical methods. The semiconducting substrate is characterized by its dielectric constant and conductivity. A critical conductivity /spl sigma//sub min/ exists and is related to the cross sectional and material parameters. If the substrate conductivity is given by /spl sigma//sub min/ then the attenuation constant of the line is a minimum. The same value of conductivity yields minimum phase distortion at maximum bandwidth. If the conductivity is larger than /spl sigma//sub min/ the substrate acts as a poor conductor with associated skin effect; if it is smaller, lossy dielectric behavior results. Analysis shows that it is appropriate to subdivide the frequency range into three intervals. The lowest-frequency interval is characterized by propagation which resembles diffusion. This is caused by the loss in the dielectric layer. The next frequency range extends to some upper frequency which is determined by substrate conductivity and the cross-sectional dimensions. In this interval, the phase velocity of the fundamental mode is controlled by the ratio of dielectric to semiconductor thickness, which, if typical interconnections are considered, implies a very low velocity. This property indicates that the structure can serve as a delay line. Further increases in frequency result in higher phase velocities. Skin effect and dielectric loss behavior describe the propagation in this third interval.     

Dielectric ring resonators loaded in waveguide and on substrate

A rigorous mode matching technique is used to analyze the dielectric ring resonators loaded in a waveguide and on top of a substrate. Variation of several lowest order modes' resonant frequencies as a function of structure parameters is presented and is shown to be helpful for optimization of spurious mode separation. Two-dimensional electric and magnetic field line patterns and three-dimensional field intensity distributions of the ring resonators are plotted and provide information for mode excitation, coupling, and spurious mode suppression. Coupling between two dielectric ring resonators loaded in a metallic cavity are analyzed. The dielectric ring resonators are used to design a C-band elliptic function dual mode bandpass filter employing HE₁₁ modes. Experimental results are presented and show excellent agreement with the analytical solutions