Dielectric Line Research Articles

Variation of Transient-response in Open-ended Microstrip Lines with Optically-controlled Microwave Pulses

In this paper we develop a method to observe faults in semiconductor devices and transmission lines by calculating the variation of the reflection function in a dielectric microstrip line that has an open-ended termination containing an optically induced plasma region. It is analyzed with the assumption that the plasma is distributed homogeneously in laser illumination. With the non linear material of degradation, the concentration of the carrier in the part of the material has changed. Since the input wave has produced the phenomenon of reflection, the input signal to the open-ended microstrip lines can be observed on reflection to identify the location of the fault. The characteristic impedances resulting from the presence of plasma are evaluated by the transmission line model. The variation of the reflection wave in the microwave system has been calculated by using an equivalent circuit model. The transient response has been also evaluated theoretically for changing the phase of the variation in the reflection. The variation of characteristic response in differentially localized has been also evaluated analytically.

Veloce: A Compact Pulser for Magnetically Driven Isentropic Compression Experiments

The use of magnetic fields to isentropically compress materials for equation-of-state studies has been first demonstrated on the Z machine at Sandia National Laboratories. Sharing similarities with the GEPI pulser, a compact pulser has been designed and built, focusing on isentropic compression experiments. In order to achieve high compacity and fast turn around, the design is built around a solid dielectric transmission line to couple current from eight low-inductance capacitors that are switched with ultra-low-inductance multichannel gas switches operating in dry air at atmospheric pressure. A peaking stage made of 72 capacitors enhanced by a low-inductance multichannel sharpening switch brings the fundamental rise time of the pulser down to 350 ns (10%-90%). A set of inductances in parallel with the sharpening switch as well as using various gases into this switch allow us to modify the current wave shape. The pulser delivers a peak current of 4 MA at a charge voltage of 80 kV on a short circuit. The rise time can be lengthened to around 650 ns for a current of 4.2 MA. The use of postholes convoluting in a solid dielectric insulation design makes that pulser unique, as well as its compact size, ease of use, and ease of access to the load.

Alternative Photoresist Removal Process to Minimize Damage of Low-k Material Induced by Ash Plasma

Dry ashing of photoresist (PR) using oxygen-containing plasma applied subsequently to an etch plasma leads to degradation of porous low-k material. The surface region is substantially depleted in carbon. The low-k film becomes more hydrophilic after being subjected to plasma etch and especially ash process as evidenced by water absorption results. The amount of absorbed water into a 30% porosity film at moisture saturation is estimated to be about 15% of the film volume, which corresponds to 50% of the total pores in the low-k film. A wet, alternative means for PR removal based on dissolution of PR in organic solvents combined with physical forces is presented. Under certain conditions, megasonic cleaning resulted in complete removal of the PR layer without damaging of the dielectric lines. These results suggest that the PR crust is permeable to these solvents and that out-diffusion of dissolved bulk PR also occurred through the crust. Dissolution of bulk PR in organic solvents first makes the PR structure more fragile, then the physical energy helps to remove the remaining crust mechanically without dissolving it. Compared to plasma ashing, solvent strip shows no carbon depletion and no significant increase in k-value.

Efficiency of reducing and oxidizing ash plasmas in preventing metallic barrier diffusion into porous SiOCH

This work focuses on the efficiency of reducing and oxidizing plasma chemistries in preventing metallic barrier diffusion into porous dielectric materials (SiOCH with a k value close to 2.2, porosity content around 40%). The ash processes have been performed on SiOCH coated blanket and patterned wafers in either reactive ion etching (RIE) or downstream (DS) reactors. The Rutherford backscattering spectroscopy technique (RBS) has shown that titanium based compounds diffuse into the blanket porous SiOCH without treatment during a typical TiN barrier deposition process by chemical vapor deposition (CVD). The metallic barrier diffusion is strongly limited on blanket wafers when the porous SiOCH has been previously modified (partially or fully) by ash plasmas (RIE-O 2, RIE-NH 3, DS-H 2/N 2 and DS-O 2/N 2) while the metallic barrier diffusion occurs with no modifying ash plasmas (DS-H 2/He). We have shown that ellipsometric porosimetry (EP) measurements clearly point out that no complete pore sealing is achieved with all the investigated ash plasmas. Energy-filtering transmission electron microscopy experiments (EFTEM) performed on single damascene structures have revealed significant titanium diffusion into the porous dielectric lines for DS-H 2/He and RIE-O 2 and sidewalls modification of the porous SiOCH lines (lower C/O ratio) for all the ash plasmas. The RC product (resistance × capacitance) have been extracted from the single damascene structures and the evolution of RC product will be discussed in terms of lines modification (titanium diffusion and porous SiOCH modification).

도파관 방향성 결합기를 갖는 60 GHz 대역 Non-Radiative Dielectric 도파관 혼합기

본 논문에서는 점 대 점 통신망으로 수요가 증가하고 있는 60 GHz 대역 무선 통신 장비의 주요 부품인 혼합기를 non-radiative dielectric 도파관으로 구현하였다. Non-radiative dielectric 도파관 혼합기의 제작에 있어서 가장 어려웠던 것이 유전체 선로 결합기의 구현이었는데, 유전체 선로를 정해진 곡율로 형상화하는 것과 정확한 간격으로 위치시키는 것이 쉽지 않기 때문이다. 이 때문에 유전체 선로 결합기를 갖는 혼합기의 경우 일정한 성능을 갖도록 제작하는 것이 매우 힘들었다. 본 논문에서는 유전체 선로 결합기를 도파관 방향성 결합기로 대체하여 가공을 통해 제작이 가능케 함으로써 결합기가 일정한 특성을 갖도록 하였다. 그 결과로 혼합기의 생산성이 획기적으로 개선되었다. 본 논문을 통해 구현된 혼합기의 설계 주파수는 RF 및 LO는 <TEX>$57{\sim}64\;GHz$</TEX>이고, IF는 <TEX>$DC{\sim}2\;GHz$</TEX>인데, LO가 10 dBm, 60 GHz인 조건에서 <TEX>$60{\sim}62\;GHz$</TEX>의 RF 입력에 대한 하향 변환 손실은 <TEX>$10{\pm}1\;dB$</TEX>로 측정되었다. In this paper, the mixer was implemented in the non-radiative dielectric waveguide that is the main component of 60 GHz band radio telecommunications equipment which a demand increases for the purpose of point-to-point communication network. As to the manufacture of the non-radiative dielectric waveguide mixer, it was the implementation of the dielectric line combiner to be most difficult. The thing which that gives shape to the curvature which is the dielectric line determined and the to place in the exact interval thing are easy. For this reason, it was very difficult to make in order to have the regular performance in the case of the mixer having the dielectric line combiner. In this paper, since the dielectric line combiner was replaced with the waveguide directional coupler and the manufacture was possible through a processing it had the characteristic that a combiner is fixed. In result, the productivity of a mixer was innovatively improved. The design frequency of the mixer implemented through this paper RF and LO are <TEX>$51{\sim}64\;GHz$</TEX>. IF Is <TEX>$DC{\sim}\;GHz2$</TEX>. The down conversion loss toward the RF input of <TEX>$60{\sim}62\;GHz$</TEX> was measured by <TEX>$10{\pm}1\;dB$</TEX> in the condition that LO is 10 dBm, 60 GHz.

Decreasing power losses in multilayer dielectric-loaded accelerating structures

We have studied the possibility of increasing the efficiency of dielectric-loaded accelerating (DLA) structures. It is shown that the level of losses in DLA structures can be significantly decreased using the Bragg principle of waveguide design for microwave radiation focusing along the axis. The waveguide lining comprises a set of layers with alternating high and low values of permittivity, which decreases the magnetic field intensity in the external metal shell of the accelerating structure. The results of calculations are presented for the TM 03 mode with a frequency of 11.4 GHz in DLA structures of the two types, with two-and four-layer lining, which show a decrease in the level of losses from −14 to −2 dB/m in the case of multilayer dielectric lining.

携帯電話用ＣｏＦｅＢ磁性薄膜方向性結合器の大振幅信号伝送特性

A directional coupler using a CoFeB magnetic/polyimide dielectric hybrid transmission line was fabricated and evaluated under a large-signal transmission condition from 0.5 to 2 W. The device consists of a [polyimide (1μm)/CoFeB (1μm)/polyimide (1μm)] sandwich between upper Cu coupled lines (3μm thick and 12μm wide) and a lower Cu ground plane (3μm). The electromagnetic coupling between the top main line and the sub-line is composed of the electric field coupling due to the stub capacitors and the magnetic field coupling through the inner magnetic film. The fabricated CoFeB magnetic thin film directional coupler exhibited excellent large-signal transmission characteristics even at a rating power of 2 W in a real cellular phone application. In addition, such a large-signal characteristic was acceptable for a wideband frequency of 0.8 to 2.4 GHz, which was mainly due to the non-resonance operation.

Computation of the Capacitance of the Inhomogeneous Insulated Transmission Line

A boundary element method (BEM) procedure to obtain the capacitance of inhomogeneous insulated transmission lines is presented. The geometry consists of multiple, parallel and insulated conductor cylinders. The BEM matrix equation associated with piecewise homogeneous insulated transmission line is derived. Two representative computational examples, eccentric coaxial cable partially filled with dielectric and transmission line consisting of two parallel dielectric-coated cylinders, are given to validate the accuracy and efficiency of the BEM.

Characteristics of low K thin film microstrip line on standard lossy silicon substrate for radio frequency integrated circuits

AbstractIn this paper, effective dielectric constant, line attenuation, and characteristic impedance of thin film microstrip line (TFML) on polyimide dielectric as interconnection for radio frequency integrated circuits is investigated. The TFML is fabricated on low cost low resistivity silicon substrate (ρ≤10 Ω cm) by incorporating a spin‐on dielectric polyimide and sputtering of aluminum. An accurate on‐wafer‐procedure for extracting the microwave characteristics of TFML up to 50 GHz is described and the method is successfully applied to low‐K polyimide deposited on the silicon. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 79–83, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22052

The Early History of Western Pulsed Power

The development of submicrosecond pulsed power in the U.K. and USA between 1960 and 1970 is described. Novel short-pulse (tens of nanoseconds) X-ray tubes driven by stacked solid dielectric striplines were devised at the Atomic Weapons Research Establishment, Aldermaston, U.K. for radiography. The importance of nuclear weapons effects simulation then motivated a very rapid development of new types of pulse generator in the USA to drive scaled-up tubes of this type. Prominent among these pulse generators were the Marx-driven liquid dielectric pulse lines that form the basis of many present-day pulsed power generators.

On the Quasi-Left-Handed Transmission Line with Gyrator Loading

This paper treats transmission characteristics of periodic structure of ferrite gyrator circuit with both theory and experiment, which is loaded into usual distributed constant line with and without lumped capacitor. Following three types of periodic structure of gyrator circuit are proposed: basic structure of periodic gyrator circuit, quasi-LH gyrator circuit with series capacitance loading, and quasi-LH gyrator circuit with parallel capacitance loading. Moreover, replacing the parallel capacitance with a resistance, a periodic structure of isolator circuit is proposed. Scattering parameters of gyrator circuit are derived with help of equivalent circuit model. Left handed transmission behavior of backward wave is discussed from dispersion curves. Experiments were undertaken using periodic structure of dielectric microstrip line and gyrator circuit fabricated on the ferrite substrate. Experimental results having wide band nonreciprocal characteristics are discussed with theory.

Attenuation of a shielded rectangular dielectric rod waveguide

The attenuation coefficient of a rectangular dielectric line enclosed by a rectangular shield is obtained by the use of a rigorous mode-matching method to calculate the required mode field intensity. The cross section of the waveguide is overlaid by a grid, and numerical integration is used to determine the power flow, dielectric, and conductor losses and respective attenuation coefficients. To obtain experimental verification, a length of waveguide was made into a resonator, and measured and calculated Q factors were compared. The results for the E/sup y//sub 11/ mode show how the influence of the shield decreases with distance. This is relevant to the design of dielectric waveguide structures and in filter applications where dielectric resonators are used.

Traceable high-precision impedance measurements for the millimetre-wave band using dielectric waveguide transmission lines

Currently, the UK&apos;s national standards for impedance measurements are only available for frequencies up to 50 GHz in a coaxial line and 110 GHz in a metallic rectangular waveguide. No standards exist above these frequencies. A need to provide measurement standards and measurement assurance above these frequencies has led to research into a new form of impedance standard for precision metrology applications across the entire millimetre-wave band and perhaps beyond (i.e. extending to at least 300 GHz). We report the development of the new standards and other devices that utilise a dielectric waveguide as the transmission medium, and we show how these standards can be used to calibrate measuring instruments, such as vector network analysers (VNAs), and to provide traceability to national standards.

Characterising beadless air lines as reference artefacts for S-parameter measurements at RF and microwave frequencies

Beadless coaxial air dielectric transmission lines can be used as fundamental reference devices for S-parameter measurements at RF and microwave frequencies. However, for these lines to be used for such applications, they must first be characterised accurately in terms of their impedance and propagation characteristics. This includes assessment of the small amount of loss in the line and the associated impact of this loss on other characteristics. A simple method is presented whereby the loss is determined experimentally using a vector network analyser (VNA). The determined loss can then be used to characterise the line so that it can be used for a range of high-precision metrology applications. Two such applications are given: determination of the actual frequency-dependent characteristic impedance of a line; and use of the line&apos;s phase constant to verify VNA phase measurements.

Effects from the Thin Metallic Substrate Sandwiched in Planar Multilayer Microstrip Lines

This paper studies the dispersion characteristics of open multilayer microstrip lines with a thin highly-conductive metallic substrate using the spectral domain approach. From the numerical results, it is found that, in both lossy (metal-insulator-silicon structure such as Si-SiO2) and lossless configurations (thin metal between lossless dielectric microstrip line), at the low frequency range, this thin metallic substrate can excite slow waves. And accordingly the frequency dependent transmission-line characteristics of interconnects, such as propagation constant, attenuation and the characteristic impedance, can change remarkably with the existence of the thin metallic substrate.

Low-loss terahertz ribbon waveguides

The submillimeter wave or terahertz (THz) band (1 mm-100 microm) is one of the last unexplored frontiers in the electromagnetic spectrum. A major stumbling block hampering instrument deployment in this frequency regime is the lack of a low-loss guiding structure equivalent to the optical fiber that is so prevalent at the visible wavelengths. The presence of strong inherent vibrational absorption bands in solids and the high skin-depth losses of conductors make the traditional microstripline circuits, conventional dielectric lines, or metallic waveguides, which are common at microwave frequencies, much too lossy to be used in the THz bands. Even the modern surface plasmon polariton waveguides are much too lossy for long-distance transmission in the THz bands. We describe a concept for overcoming this drawback and describe a new family of ultra-low-loss ribbon-based guide structures and matching components for propagating single-mode THz signals. For straight runs this ribbon-based waveguide can provide an attenuation constant that is more than 100 times less than that of a conventional dielectric or metallic waveguide. Problems dealing with efficient coupling of power into and out of the ribbon guide, achieving low-loss bends and branches, and forming THz circuit elements are discussed in detail. One notes that active circuit elements can be integrated directly onto the ribbon structure (when it is made with semiconductor material) and that the absence of metallic structures in the ribbon guide provides the possibility of high-power carrying capability. It thus appears that this ribbon-based dielectric waveguide and associated components can be used as fundamental building blocks for a new generation of ultra-high-speed electronic integrated circuits or THz interconnects.

Self-conditioning 고정입자패드를 이용한 CMP

Chemical mechanical polishing(CMP) process is essential technology to be applied to manufacturing the dielectric layer and metal line in semiconductor devices. It has been known that overpolishing in CMP depends on pattern selectivity as a function of density and pitch, and use of fixed abrasive pad(FAP) is one method which can improve the pattern selectivity. Thus, dishing & erosion defects can be reduced. This paper introduces the manufacturing technique of FAP using hydrophilic polymers with swelling characteristic in water and explains the self-conditioning phenomenon. When applied to tungsten blanket wafers, the FAP resulted in appropriate performance in point of uniformity, material selectivity and roughness. Especially, reduced dishing and erosion was observed in CMP of tungsten pattern wafer with the proposed FAP.

New design formulas for microstrip transmission lines using high‐dielectric substrate

PurposeCharacterisation and use of dielectric materials with high permittivity are one of the most developed areas of research in microwave circuit simulation. This is mainly because of their various applications in VHF/UHF and microwave frequencies (correlators, instrumentation systems, …). The primary virtue of high‐dielectric substrates for microwave circuits is the reduced size. Since the high dielectric microstrip line also exhibit low loss and useful impedance range, this class of circuits will undoubtedly find wide applications in microwave integrated circuitry.Design/methodology/approachOwing to the complexity of the electromagnetic problem, numerical methods become an indispensable tool for analysis and modeling of electromagnetic structures. They are the basis to set‐up computer‐aided design (CAD) packages. These models must be accurate, reliable, easily extracted and need limited computational requirements. Since there was a demand for a model able to describe these parameters accurately, an extension of the spectral domain approach (SDA) is proposed for microstrip lines with high permittivity. The analysis is based on the solution of a system of algebraic equations, which are derived from Galerkin's technique in the spectral domain.FindingsAnalytical expressions are deduced by curve‐fitting techniques. These expressions can be easily implemented in a CAD simulation tool to design wireless communication components. In this paper, we have developed accurate and suitable general expressions for characteristic parameters for a wide range of εr between 1 and 500. The computed results were compared to those available in the literature when possible. In order to validate our models for high values of dielectric constant (128 &lt; εr&lt;500), neural models were generated for the characteristic impedance and effective permittivity. A very good agreement is demonstrated.Originality/valueThe originality of this paper consists on the development of design formulas to characterise the microstrip lines with high dielectric constant substrate. Closed form equations are almost non‐existent in the technical literature since the available design formulas have been developed only for dielectric media value εr not exceed 128.

Three‐dimensional numerical analysis on discharge properties of microwave excited ring dielectric line surface wave processing plasma device

AbstractA three‐dimensional simulation code with the finite difference time domain (FDTD) method combined with the electron fluid model has been developed for the microwave excited surface wave plasma in the RDL‐SWP device. This code permits the three‐dimensional numerical analysis of the spatial distributions of electric field, power absorption, electron density, and electron temperature. At a low gas pressure (about 10 mTorr), the numerical results were compared with the experimental measurements that show the validity of this 3D simulation code. A simplified analysis assuming that the electron density is spatially uniform has also been studied and its applicability is evaluated by the comparison of the 3D simulation and the analytical solutions. The surface wave eigenmodes are determined by the electron density, and it is found that the structure of the device strongly influences the spatial distribution of the electric fields of surface waves in a low‐density area (ne &lt; 3.0 × 1011 cm−3). A method to irradiate by microwave the whole surface area of the plasma is proposed. The method is found to be effective in obtaining a high uniformity distribution of electron density. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 150(4): 1–12, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10333

Dielectric slab Rotman lens with tapered slot antenna array

A new type of Rotman lens is presented for micro/millimetre-wave applications, such as collision avoidance radar. A dielectric slab Rotman lens is proposed to reduce the conductor loss in addition to the mutual coupling in a form which can be implemented easily at millimetre-wave frequencies. The proposed lens consists of a dielectric slab and slot lines whereas conventional lenses are constructed with parallel conducting plates. The dielectric slab excited in TE/sub 0/ mode shows a high degree of confinement for the fields, and low dispersion, and has an appropriate feed structure for the dielectric slab lens. A prototype lens was designed and fabricated with nine beam ports and nine array ports together with nine tapered slot antennas. This lens system was tested in the range from 10 to 15 GHz and the measured beam widths are about 15/spl deg/ at 13 GHz. The measurements also show that the mutual coupling between the beam ports decreases with frequency and its efficiency is about 34.6%. The overall performance is comparable to that of conventional Rotman lenses even though a spillover loss is presumed at the frequency of the implementation. It is expected that at millimetre-wave frequency the dielectric slab Rotman lens will have lower conductor loss and lower mutual coupling than conventional Rotman lenses.