High performance microshield line components

Several millimeter-wave passive components have been fabricated using the microshield transmission line geometry, and their performance is presented herein. Microshield is a quasi-planar, half-shielded design which uses a thin dielectric membrane (1.5 μm) to support the conducting lines. This approach provides a nearly homogeneous, air-filled environment and thus allows extremely broad-band TEM operation. This paper examines the conductor loss and effective dielectric constant of microshield lines and presents results on transitions to conventional coplanar waveguide, right-angle bends, different stub configurations, and lowpass and bandpass filters. Experimental data is provided along with numerical results derived from an integral equation method. The microshield line is shown to be very suitable for high performance millimeter and submillimeter-wave applications     

V-groove (VMOS) conductively connected charge coupled devices

A new Conductively Connected Charge Coupled (C4D) device is described. This structure achieves directionality of charge transfer using a barrier existing at the apex of a V-groove anisotropically etched into the silicon. The design of the device is discussed and the properties of the barrier are determined from a numerical solution of Poisson's equation. The feasibility of the structure is demonstrated experimentally by operating fabricated devices as digital shift registers. The structure has many advantages. The barrier can be obtained using simple processing techniques and its small dimensions may allow an increase in packing density. Furthermore, the structure has a built-in bias charge which always transfers to the receiving well irrespective of whether a charge packet is present or not.     

Simple and explicit formulas for the design and analysis ofasymmetrical V-shaped microshield line

This paper presents some simple, explicit and practical formulas for the evaluation of the quasi-TEM characteristic parameters of asymmetrical V-shaped microshield line, based on a conformal mapping procedure. These formulas give very accurate results in terms of elementary functions rather than the exact solution in terms of difficult functions. Two sets of expressions are described using first and second order approximations. These equations are easy to implement, thus making it an excellent choice for use in computer aided design, analysis and optimization of V-shaped microshield structures     

Characterization of two coupled radial line transformers in dual-diode millimeter wave oscillators

Two mutually coupled radial line transformers mounted in a common rectangular waveguide of dual—diode millimeter wave oscillator are characterized by a hybrid technique based on Galerkin's method combined with collocation technique. The external circuit impedances looking outside from each of two active devices are calculated. A large number of numerical results of the external circuit impedances as a function of the structural parameters have been obtained. Some original conclusions have been made, which are helpful to the design and the adjustment of the dual—diode oscillators.     

Characteristic impedance of microshield lines with arbitrary shieldcross section

A generalized potential-matching method incorporating reflection matrices is developed to calculate the capacitance of microshield lines with trapezoidal, circular, and V-shaped shields. Both completely shielded and half-shielded lines are analyzed. The effects of membrane thickness, strip width, and gapwidth on the characteristic impedance are studied     

V-groove substrate fed logic

A new substrate fed logic structure is presented which makes use of V-groove silicon etching. Experimental results are presented for the devices. A speed-power product below 1 pJ was obtained despite the large area of the test structures and the use of conventional bipolar processing. Further improvement in performance is expected by optimising the process parameters.     

The V-groove multijunction solar cell

A new type of silicon photovoltaic converter has been developed called the V-Groove Multijunction (VGMJ) solar cell. The VGMJ solar cell consists of an array of many individual diode elements connected in series to produce a high-voltage low-current output. All the elements of the cell are formed simultaneously from a single silicon wafer by V-groove etching. The results of detailed computer simulations predict a conversion efficiency in excess of 24 percent for this cell when it is operated in sunlight concentrated 100 or more times. The advantages of this cell over other silicon cells include the capability for greater than 20-percent conversion efficiency with only modest bulk carrier lifetimes, a higher open-circuit voltage, a very low series resistance, a simple one-mask fabrication procedure, and excellent environmental protection provided by a glass front surface.     

Self-biased hexagonal ferrite coupled line circulators

The simulated performance for novel hexagonal FCL circulators is presented for the first time. Compared to conventional FCL circulators, these structures do not require external biasing and have the advantages of smaller size and lower conductor and dielectric loss. Simulations show that the size decreases as the value of 4/spl pi/M/sub eff/ of the hexaferrite increases.     

Modulation response of V-groove quantum-wire lasers

We analyze the modulation speed of an InGaAs-InP quantum-wire laser of a V-groove-shaped structure. The bandwidth is affected by the optical confinement /spl Gamma/, exhibiting a maximum at /spl Gamma/=0.016. The maximum bandwidth for the intrinsic device is 20 GHz as a result of a calculation based on the experimentally obtained cross section of the device and including the nonparabolicity of the conduction and valence bands. We discuss the reduction of the bandwidth of the device itself by summarily considering the influence of the roll-off time and the cavity length as well as the nonlinear gain suppression.     

Millimetric V-groove guide and components

A characteristic equation of single V-groove guide has been derived using the transverse resonance technique. This equation is much less complex and tedious to solve when compared with that obtained by the conformal mapping technique. The computed results are within 1% of the published experimental values for the cut-off wavelengths at X-band and 100 GHz. The present analytical approach is to approximate the central groove region by a large number of rectangular steps and the previously derived analytical solution for the rectangular-groove guide are applied to predict the propagation characteristics of single V-groove guide. A number of components in V-groove guide which have very similar characteristics to those of the rectangular-groove counter-part have been reviewed. It is noted that both the E-plane and H-plane cylindrical bends in both rectangular-groove and V-groove guides had unacceptably high-loss and a satisfactory solution have yet to be reached.     

Analytical analysis of circular-shaped microshield and conductor-backed coplanar waveguide

In this paper, a new type of circular-shaped microshield and conductor-backed coplanar waveguide is proposed. Analytic closed-form expressions for characteristic impedance and effective dielectric constant for the new line are obtained using conformal mapping method under the assumption of pure-TEM propagation and zero dispersion. The new waveguide proposed by this paper can reduce radiation to much less than the conventional coplanar waveguide and microstrip, and can reduce the current concentration at both the edges of the strip conductor.     

Optimisation of dimensions of single V-groove guide

The optimum dimensions of a single V-groove guide for a frequency band were found to be more critical than that at a fixed frequency. The dimensions of this guide were optimised at X-band (8?12.4 GHz).     

Sub-40 nm SOI V-groove n-MOSFETs

We present output and transfer characteristics of single-gated, 36 nm, 46 nm and 56 nm channel length SOI MOSFETs with a V-groove design. For the shortest devices we find transconductances as high as 900 μS/μm and drive currents of 490 μA/μm at V_gs - V _th=0.6 V. The V-groove approach combines the advantages of a controlled, extremely abrupt doping profile between the highly doped source/drain and the undoped channel region with an excellent suppression of short-channel effects. In addition, our V-groove design has the potential of synthesizing devices in the 10 nm range     

Design procedure for inhomogeneous coupled line sections

Design formulas are presented, along with a procedure for the design of inhomogeneous coupled line sections as an approximation to a series open-circuited stub for application in the realization of microwave pseudo-high-pass filters. The accuracy of the design equations is evaluated through the design and test of a seventh-order filter and it is found that the formulation predicts the performance of the section well beyond the quarter-wave frequency     

Dual-band, cross coupled branch line coupler

A novel branch line coupler structure is proposed with application to the dual band operation. The proposed structure has additional cross coupling branches to the conventional branch hybrid coupler. Additional design freedom can be obtained using the proposed scheme, which can serve many useful purposes such as the dual band operation of the branch line coupler.     

Square-wave propagation along coupled coplanar transmission line

Results of modelling square-wave propagation along coupled coplanar transmission line with grounded centre strip conductor are presented. Improved agreement between numerical and experimental data for the near- and far-end crosstalk voltages has confirmed practical significance of inclusion of multimode propagation in non-ideally grounded coplanar lines.     

Epitaxial V-groove bipolar integrated circuit process

A new four-mask "V-groove" process for the fabrication of bipolar integrated circuits has been developed. The process utilizes epitaxial ν/n⁺/n^-layers and anisotropic etching oflangle100ranglesilicon to eliminate the buried layer and isolation diffusions as well as the need for masking the base diffusion of the standard six-mask bipolar integrated circuit process, n-p-n transistor, resistor, and Schottky diode characteristics are equivalent to or exceed those of the standard process. A five-mask V-groove process provides improved lateral p-n-p transistors compared with the four-mask approach. The V-groove integrated circuit structure offers simpler processing, smaller isolation capacitances, lower parasitic collector resistances, larger packing densities, and higher junction breakdown voltages than standard bipolar integrated circuits without degradation of other properties.     

微屏蔽三线对称结构带通滤波器设计

对薄膜支撑空腔型微屏蔽传输线进行分析,提出微屏蔽传输线的物理结构。为了验证微屏蔽传输线在毫米波应用的优势,利用类比平行耦合微带线滤波器的方法设计了一种4阶切比雪夫三线对称结构微屏蔽线滤波器。通过对该微屏蔽腔体结构进行HFSS仿真,得到中心频率35 GHz的宽带滤波器,带宽15 GHz,带内插损小于0.5 dB,带外抑制>40 dB@53 GHz,器件尺寸8.24 mm×1.5 mm×0.65 mm。该设计为基于平面传输线的滤波器在毫米波频段的实现提供了一种可行的方法。     

A V-groove Schottky-barrier FET for UHF applications

The structure and fabrication of a Schottky-barrier gate FET (SB-VFET) with a nonplanar conduction channel fabricated by preferential etching of silicon axe described in this paper. The device exhibits high transconductance and low series resistance and is suitable for low-noise applications at the lower end of the microwave spectrum. The low-frequency transconductance per unit channel length of 6 µm-gate device was typically 18.8 mΩ/mm, the gate breakdown voltage was 7 V, and the cutoff frequency was 1.3 GHz. The noise figure with the device biased for maximum gain was typically 4 dB at 350 MHz. A simplified theory adequate for engineering design purposes is proposed to explain the characteristics of the device and an equivalent circuit is used to model the high-frequency behavior. The theory is shown to be in agreement with experimental results. Frequency limitations of the present device are discussed and further improvements are proposed.     

The dominant mode in closed V-groove guide

The structure of closed V-groove guide is similar to that of open one, but it can prevent energy from leaking out of the guide. In this paper, the dominant mode in the closed V-groove guides are analysed by using the approach of equivalent network with transverse resonance. The results have important practical values in design, manufacture and application of V-groove guide.