Slot-Line Field Components (Correspondence)

Formulas derived by mode summation give the six B- and H-field components in the various air and dielectric regions of a slot-line cross section. These formulas are valid except when very close to the slot, where approximations in the analysis cause a large error. A quasi-static method yields a second set of formulas that apply near the slot. Thus the field is determined satisfactorily in all parts of the cross section. Graphs of the H components show that elliptical polarization exists, with the best approach to circularity near the slot and near the opposite surface of the substrate. Quantitative field data are useful for analysis and design of slot-line components, such as ferrite devices, dielectric-resonator filters, directional couplers, and broad-band transitions to coaxial line or microstrip.     

Slot Line on a Dielectric Substrate

Slot line consists of a narrow gap in a conductive coating on one side of a dielectric substrate, the other side of the substrate being bare. If the substrate's permittivity is sufficiently high, such as /spl epsiv//sub r/ = 10 to 30, the slot-mode wavelength will be much smaller than free-space wavelength, and the fields will be closely confined near the slot. Possible applications of slot line to filters, couplers, ferrite devices, and circuits containing semiconductor elements are discussed. Slot line can be used either alone or with microstrip line on the opposite side of the substrate. A "second-order" analysis yields formulas for slot-line wavelength, phase velocity, group velocity, characteristic impedance, and effect of adjacent electric and magnetic walls.     

The Effect of Surface Metal Adhesive on Slot-Line Wavelength (Short Papers)

An investigation of the dependence of slot-line wavelength upon a thin layer of adhesive between metal and substrate is described. It is shown that the presence of adhesive will cause an increase in wavelength when the dielectric constant of the adhesive is less than that of the substrate. Experimental results are presented which show this dependence for a variety of surfaces and adhesives. A perturbation expression is given which permits correction of experimental data for comparison with theory when this effect occurs.     

Microstrip-Slot Coupler Design-Part II: Practical Design Aspects

Practical aspects of designing microstrip-slot couplers on an Al/sub 2/O/sub 3/ ceramic substrate (epsilon/sub r/ = 9.8) are treated in supplementation of the theoretical analysis of the coupler presented in Part I. Comparison with implemented couplers yields rules for specification of the reference planes at the ends of the coupling section, for the appropriate choice of definition for the slot-line characteristic impedance. Design data of the standard versions of the microstrip transmission line, the slot line are shown to be adequate for the microstrip-slot coupler. Computed S -parameter curves plotted for various 3-dB couplers yield information on realizable transmission characteristics.     

基于缝隙单元的3D多模频率选择结构研究

为了实现高性能的滤波响应,提出了一类新型基于缝隙单元的三维多模频率选择结构。首先以传统2D“十字”缝隙型频率选择表面及其级联结构为例,阐述了2D频率选择表面在结构、性能上的优缺点。为了进一步改善滤波性能,分别提出了基于均匀缝隙单元、阶梯阻抗缝隙单元、多模吸波式缝隙单元的3D频率选择结构。该类型频率选择结构可基于传输线理论进行分析,在设计频段内可产生多个谐振模式而展现出高性能滤波响应,故在微波毫米波频段具有良好的应用前景。     

Broadside-Coupled Slot-Line Field Components (Short Paper)

This paper presents expressions for the odd- and even-mode electric field components and also the magnetic field components in the air, overlay, and dielectric regions of the broadside-coupled slot-line structure. These expressions are numerically computed, and the fields in the cross section and the Iongitudinal section are illustrated. The surface current distribution on the metal surfaces are also illustrated.     

Miniature high-Q double-spiral slot-line resonator filters

A new class of low insertion-loss miniaturized filters using slot-line resonators is proposed. Miniaturization is achieved by terminating the slot line with a double-spiral inductive termination at both ends. Using this miniaturized resonator, both positive and negative couplings may be realized, and therefore, both standard coupled-line and cross-coupled quasi-elliptic filters are realizable. The unloaded Q of these slot-line filters is considerably higher than that of miniaturized microstrip filters of comparable dimensions due to the inherent higher Q of the slot line. To demonstrate the validity of the design procedures and the performance characteristics, two different types of filters were fabricated and tested. One is a four-pole Chebyshev filter and the other is a quasi-elliptic filter where, in each case, the full-wave simulations show very good agreement with measurements.     

Study of the dispersion characteristics of planar chiral lines

This paper analyzes the dispersion characteristics of the fundamental modes of some basic chiral planar transmission lines: microstrip, slot-line, coplanar waveguide (CPW), and a coupled microstrip line, including the possible frequency dependence of the chiral parameters. The dispersion characteristics are computed after finding the zeros of the determinantal equation resulting from the application of the Galerkin method in the spectral domain. Because of the biisotropic nature of the substrate, a 4×4 matrix differential equation has been solved to obtain the spectral dyadic Green's function (SDGF). This function is explicitly obtained in terms of a closed-form 4×4 transition matrix that relates the transverse electromagnetic fields at the upper and lower interface of the chiral substrate. This fact is key to developing fast computer codes since it avoids numerical matrix exponentiations. The numerical results have shown that the chiral nature of the substrate basically adds an additional parameter to control the propagation characteristics of the analyzed lines and, in general, makes the lines more dispersive, showing even resonant-like behavior     

Wire-Bond Free Technique for Right-Angle Coplanar Waveguide Bend Structures

This paper presents a new wire-bond free technique for suppressing slot-line mode excitation in coplanar waveguides (CPWs) bends. The suppression of slot-line mode is obtained by applying a slow wave structure to the shorter slot of the right-angle bend. The structure is modified into a circular-shaped bend where the slow wave compensation is then used to equalize the electrical length of the inner and outer slots. The insertion loss of the modified CPW bend with slow wave structure is evaluated on a silicon substrate and is similar to straight CPW lines with return loss $({ S}_{11})$ values below $-$20 dB over a 50-GHz bandwidth.      

3-D CMOS Circuits Based on Low-Loss Vertical Interconnects on Parylene-N

parylene-N is used as a dielectric layer to create ultra low-loss 3-D vertical interconnects and coplanar waveguide (CPW) transmission lines on a CMOS substrate. Insertion loss of 0.013 dB for a 3-D vertical interconnect through a 15-$mu$ m-thick parylene-N layer and 0.56 dB/mm for a 50- $Omega$ CPW line on the parylene-N layer (compared to 1.85 dB/mm on a standard CMOS substrate) are measured at 40 GHz. L-shaped, U-shaped, and T-junction CPW structures are also fabricated with underpasses that eliminate the discontinuities arisen from the slot-line mode and are characterized up to 40 GHz. A 3-D low-noise amplifier using these post-processed structures on a 0.13-$mu$ m CMOS technology is also presented along with the investigation of parasitic effects for accurate simulation of such a 3-D circuit. The 3-D circuit implementation reduces the attenuation per unit length of the transmission lines, while preserving the CMOS chip area (in this specific design) by approximately 25%. The 3-D amplifier measures a gain of 13 dB at 2 GHz with 3-dB bandwidth of 500 MHz, noise figure of 3.3 dB, and output 1-dB compression point of ${+}$ 4.6 dBm. Room-temperature processing, simple fabrication, low-loss performance, and compatibility with the CMOS process make this technology a suitable choice for future 3-D CMOS and BiCMOS monolithic microwave integrated circuit applications that currently suffer from high substrate loss and crosstalk.      

Matching of active millimetre-wave slot-line antennas

The matching of a radiating, resonant structure to an active millimetre-wave device is investigated. As an active device, an IMPATT diode is considered to be matched to a planar slot-line structure. An analytical IMPATT diode model and an equivalent circuit of the slot line are used to calculate possible oscillation frequencies and large-signal modulation parameters of the diode. In the case of matching the output power is predicted. The results are in satisfactory agreement with experimental data and suggest a diode design with shorted drift regions and reduced diode area for optimum impedance matching.<>     

Suspended Slot Line Using Double Layer Dielectric

This paper presents a rigorous analysis of a) slot line on a double layer dielectric substrate, and b) slot line sandwiched between two dielectric substrates. The structure is assumed to be suspended inside a conducting enclosure of arbitrary dimensions. The dielectric substrates are assumed to be isotropic and homogeneous and are of arbitrary thickness and relative permittivity. The conducting enclosure and the zero thickness metallization on the substrate, are assumed to have infinite conductivity. The effect of shielding on the dispersion, characteristic impedance, and the effective dielectric constant are illustrated. These results should find application in the design and fabrication of MIC components and subsystems.     

Modeling of a monopole partially buried in a grounded dielectricsubstrate by the modal expansion method

The input impedance of a monopole antenna partially buried in an infinite grounded dielectric substrate and fed by a coaxial transmission line is calculated by the modal expansion method. The effect of the dielectric substrate on the antenna's radiated power and input impedance is numerically examined     

A New Class of Nonreciprocal Components Using Slot Line (Short Papers)

The authors present an experimental and theoretical study of edge modes in a ferrite-loaded slot line. Nonreciprocal properties are obtained over a broad frequency band. Added microstrip lines provide suitable transitions. A theory based on magnetic boundary conditions shows good agreement with the experimental results and allows a comparison with stripline devices described by Hines. In particular, the characteristics of the slot-line isolators are satisfactorily explained by this theory.     

Microstrip line on an artificial dielectric substrate

This letter presents a new version of an artificial dielectric substrate and a microstrip line built on top of this substrate. The substrate is fabricated as a two-dimensional array of metallic posts separated from the top conductor by a thin dielectric slab. This structure can show a very high effective permittivity and can therefore offer a substantial reduction in the dimensions of microwave circuit elements.     

Characteristic Impedance of Integrated Circuit Bond Wires (Short Paper)

In microwave circuit analysis, bond wires are frequently modeled as lumped elements or sections of microstrip. These models are insufficient since part of the wire is suspended above the substrate. This paper shows numerical results that provide the line impedance and effective dielectric constant for a round wire above a grounded dielectric substrate.     

Dielectric image line groove antennas for millimeter waves, Part I: Theoretical background

Dielectric image line groove antennas are very useful for the application in the millimeter-wave region. In this first part of a two-part paper, three different types of groove discontinuities under a dielectric image line for application in millimeterwave antennas are investigated: the equivalent circuits of 1) a slot discontinuity in a metallic ground plane and 2) a slot discontinuity in the metallization of a substrate material under a dielectric image line are derived theoretically using an approximation for the electromagnetic fields of the slots. 3)The equivalent circuit of cylindrical holes in a metallic ground plane under a dielectric image line is derived from measurements. The results are used to synthesize millimeterwave dielectric image line antenna arrays as described in part II of the paper.     

Multiple microstrip lines on a multilayered cylindrical dielectricsubstrate on perfectly conducting wedge

The quasi-TEM characteristics of a class of cylindrical microstrip lines are rigorously determined. The class of microstrip lines considered consists of multiple infinitesimally thin strips on a multilayered dielectric substrate on a perfectly conducting wedge. Expressions for the potential distribution inside and outside the dielectric substrate, charge distribution on the strips, and capacitance matrix of the microstrip lines are derived. The problems of a microstrip line on a cylindrically capped wedge and on a cylindrical dielectric substrate on perfectly conducting core are also considered as special cases. Sample numerical results based on the derived expressions are given and discussed     

Artificial Dielectric Shields forIntegrated Transmission Lines

We present a novel shielding method for on-chip transmission lines built on conductive silicon substrates. The shield consists of an artificial dielectric with a very high in-plane dielectric constant, built from two patterned metal layers isolated by a very thin dielectric film. Inserted below an integrated coplanar transmission line, the artificial dielectric layer blocks the electric field of the line from entering the silicon substrate. Shielded coplanar waveguides fabricated on a conventional silicon wafer show a two- to three-fold loss reduction compared to unshielded lines at frequencies below 30 GHz.     

The future of substrate data private line networking

Private line networking for data applications using data rates equal to or less than 64 kb/s, referred to as substrate, is reviewed. Examples of substrate data applications include: automatic teller machine networks, banking teller platforms, and airline flight reservation systems. The fundamental point-to-point and multipoint topologies used in substrate data private line networking are described from both primary data and diagnostic network perspectives. Market and technology trends affecting substrate networking, including analog to digital migration, multichannel-multipoint configurations, tail extensions off DS-1 backbones, hybrid networking, service restoration, disaster recovery, LAN interconnection, and multinational networking, are discussed. Brief remarks concerning future technologies, such as ISDN and wireless applications, are presented