Abstract: The Vivaldi antenna, a form of tapered slot radiator, has been shown to produce good performance over a wide bandwidth, limited only by the traditionally used slotline to microstrip feed transition. The authors present a new antenna, the balanced antipodal Vivaldi, which incorporates an ultrawide bandwidth transition and overcomes the poor polarisation performance of the antipodal form. Good performance over a 1 to 40 frequency range has been obtained. The use of the antenna in a linear phased array has also been investigated using elements constructed on high permittivity substrate. Wideband wide angle scanning with good cross-polarisation levels is obtained.

Abstract: A novel approach for accurate and efficient modeling of monolithic microwave/millimeter wave integrated circuit (MMIC) components by using electromagnetically trained artificial neural network (EM-ANN) software modules is presented. Full-wave EM analysis is employed to characterize MMIC components. Structures for simulation are chosen using design of experiments (DOE) methodology. EM-ANN models are then trained using physical parameters as inputs and S-parameters as outputs. Once trained, the EM-ANN models are inserted into a commercial microwave circuit simulator where they provide results approaching the accuracy of the EM simulation tool used for characterization of the MIMIC components without increasing the analysis time significantly. The proposed technique is capable of providing simulation models for MMIC components where models do not exist or are not accurate over the desired region of operation. The approach has been verified by developing models for microstrip vias and interconnects in dataset circuits. A new hybrid (/spl Delta/S) modeling approach which makes use of existing approximate models for components is introduced and shown to be a more efficient method for developing EM-ANN models. An example of using EM-ANN models to optimize the component geometry is included.

Abstract: A planar lens antenna based on aperture coupled microstrip patch elements with stripline delay lines is described. Features of this design are discussed, and results for transmission coefficient magnitude against frequency are presented. The background for the development of this lens configuration is discussed in terms of a natural progression from frequency selective surfaces, and the inadequacies of simpler geometries are explained.

Abstract: PROBLEM TO BE SOLVED: To provide an integrated circuit package which can realize an ultra- high-speed operation with a simple arrangement. SOLUTION: A bias conductor pattern 6b and a signal conductor pattern 6s of a coplanar or a microstrip shape are provided on a support substrate 2 carried on a metal base 1, and a bare-chip integrated circuit 12 is mounted onto the conductor patterns 6b and 6s in the form of a flip chip. A light receiving element 11 is provided on a lower side of the bare-chip integrated circuit at a position corresponding to a groove 8 of the support substrate as a flip chip to realize an ultra-high-speed integrated circuit package. The coplanar signal line pattern 6s is provided on the upper side of the support substrate 2 whose back side is supported by the metal base 1. The bare-chip integrated circuit is die-bonded adjacent to the coplanar signal line pattern 6s so that a connection substrate 16 having a coplanar line pattern achieves connection between the coplanar signal line pattern 6s and the signal electrode on the bare-chip integrated circuit.

Abstract: Oscillators and Synchronization. Antennas and Arrays. Power Combining. Integrated and Active Antenna Testing. Active Antennas: Early Work Before 1987. Active Microstrip Patch Antennas and Power Combining. Integrated and Active Grids. Endfire Notches and Other Slotline Active Antennas. Integrated and Active Inverted Stripline Antennas and Other Active Antenna Configurations. Integrated Antennas with Passive Solid-State Devices. Beam Steering for Active Antenna Arrays and Spatial Power Combiners. Index.

Abstract: We have developed a new permeance meter in the 1 MHz-1.5 GHz range using either a microstrip pickup coil or a shielded loop pickup coil. Both pickup coils and the driving plates are free from LC resonance due to impedance matching. In the MHz range we must consider signal-to-noise ratio of the pickup coil. In the GHz range we must eliminate the voltage induced by the electric field, and an electromagnetic higher order mode in the driving plates.

Abstract: Results are presented for high performance planar W-band filters based on silicon micromachining techniques common in microsensor fabrication. Two types of micromachined planar transmission lines are studied: microshield line and shielded membrane microstrip (SMM) line. In both of these structures, the conducting lines are suspended on thin dielectric membranes. These transmission lines are essentially "floating" in air, possess negligible levels of dielectric loss, and do not suffer from the parasitic effects of radiation and dispersion. A 90 GHz low pass filter and several 95 GHz bandpass filters are tested and display excellent performance which cannot be achieved with traditional substrate supported circuits in CPW or microstrip configurations. A full-wave finite-difference time-domain (FDTD) technique verifies the measured performance of the W-band circuits and provides a basis for comparison between the performances of membrane supported circuits and equivalent substrate supported circuits.

Abstract: Dielectric resonator antennas (DRA?s) excited by a narrow-slot aperture in a conducting ground plane are analyzed using a numerical technique based upon a surface-integral equation formulation for bodies of revolution (BOR's) coupled to non-BOR geometries. An efficient matrix-solution algorithm, together with a simple microstrip transmission-line model or a delta-source model are used to comnute the antenna inmt impedance. Input impedances obtained with this technique show favorable agreement to those obtained via another numerical technique, as well as to those obtained by measurement.

Abstract: The finite-difference time-domain (FDTD) method is being widely applied to antenna and microstrip calculations. One aspect of this application is accurately and efficiently modeling antenna and microstrip feeds within the constraints of the FDTD approximations. Several relatively straightforward approaches have been suggested, including gap and frill feeds. More complicated approaches, which involve including the coaxial feed cable in the FDTD calculation space, have also been suggested. A related aspect is the desirability of reducing the number of time steps required for the FDTD calculations to converge, especially for transient excitation. We illustrate that for many geometries a simple gap model with an internal source resistance provides accurate results while greatly reducing the number of time steps required for convergence.

Abstract: The increasing complexity of electronic systems has introduced an increased potential for electromagnetic interference (EMI) between electronic systems. We analyze the radiation from a microstrip transmission line and calculate the total radiated power by numerical integration. Reverberation chamber methods for measuring radiated emissions and immunity are reviewed and applied to three microstrip configurations. Measurements from 200 to 2000 MHz are compared with theory, and excellent agreement is obtained for two configurations that minimize feed cable and finite ground plane effects. Emissions measurements are found to be more accurate than immunity measurements because the impedance mismatch of the receiving antenna cancels when the ratio of the microstrip and reference radiated power measurements is taken. The use of two different receiving antenna locations for emissions measurements illustrates good field uniformity within the chamber.

Abstract: Recently, dielectric resonator antennas (DRA) have been proposed as an alternative to the popular microstrip patch. Since then, research has continued, extending their performance capabilities and confirming their potential as low profile and efficient antenna elements for array applications. Also a single-point fed dielectric resonator antenna has been reported, capable of radiating a circularly polarized signal with a much wider axial ratio bandwidth than a similar single-point fed microstrip patch. Further capability enhancements of a dielectric resonator antenna have recently been demonstrated by fabricating the antenna from ferrite material. With a properly biased static magnetic field, it has been shown to possess frequency tuning and polarization diversity properties. The purpose of this paper is to present a novel development of a DRA which possesses a much wider operational bandwidth than previously reported. This improvement can be accomplished with a simple slot feed and without an elaborate matching circuit or a complicated stacking procedure which is generally required by the microstrip patch.

Abstract: A new stacked microstrip reflectarray, based on patches of variable size, is proposed for dual frequency operation A progressive phase distribution is achieved for the reflected wave at both frequencies by adjusting the resonant length of the patches in each elementary cell of the reflectarray

Abstract: A simple, efficient, and unified source excitation scheme for the finite-difference time domain (FDTD) analysis of both waveguides and microstrip circuits is developed and validated. In this scheme, by moving the source plane several cells inside the terminal plane and adding the excitation wave as an extra term in the FDTD equation, the interaction between the excitation and reflected waves are totally separated in time domain. Hence, for both waveguide and microstrip discontinuities, absorbing boundary conditions can be applied on the terminal plane directly. In particular, for microstrip circuits, our scheme does not induce any source distortions when a simplified field distribution is used as the excitation. Consequently, the terminal plane can be moved very close to the discontinuity and thus significant computational savings are achieved. In addition, for microstrip systems, the validity and efficiency of the Mei's simplified field distribution are evaluated and confirmed for the first time.

Abstract: The signal integrity issues at split ground and power planes are studied by 3D, time-domain, full-wave simulations and SPICE circuit simulations. Dynamics of the mode conversion between microstrip line mode and slotline mode is presented as a series of snapshots of a computer animation. Equivalent circuits based on transmission line model and mode conversion are developed and validated by published experimental data. It is also demonstrated that under certain resonance conditions, the unwanted noise coupling between two signal lines that cross the same ground slot can reach a very high percentage. Design rules for choosing the slot width for isolated ground and power islands in mixed-signal environment are also discussed.

Abstract: An accurate and efficient technique is presented for the analysis of large microstrip antenna arrays. The technique consists of an amalgamation of a spatially discrete scheme, consisting of the CG-FFT method and the complex discrete image (CDI) technique. The unique feature of this approach is the use of the spatially discrete CG-FFT for analyzing microstrip structures. The aliasing and truncation errors are thoroughly eliminated in this approach. In addition, the grad-div operators are transformed from singular Green's functions to differentiable expansion and testing functions by using Galerkin's procedure, thereby improving the accuracy and the rate of convergence. To show the accuracy and efficiency of this technique, a number of microstrip arrays, including a large microstrip reflectarray, have been studied. It is found that the simulations carried out using this technique are in very good agreement with measurements.

Abstract: A low cost window-mounted antenna system for mobile communication systems operating at frequencies in and above the 1.5 GHz band includes an annular ring aperture coupler fabricated on printed circuit boards on each side of the window, with a microstrip line etched on each of the printed circuit boards. A collinear array-type whip antenna with a 1/2-wavelength lower section is used with the coupler. A coplanar waveguide trace is printed on the outside coupling unit to form an impedance matching network for the active element. The RF signal is thus electro-magnetically coupled through the window.

Abstract: This paper describes a cavity-backed patch-antenna geometry, which features multiple dielectric layers and shorting posts. These features are exploited to design antennas which retain many of the desirable characteristics of conventional microstrip antennas, yet overcome some of their inherent disadvantages.

Abstract: A newly discovered leaky dominant mode is reported for conventional microstrip line on an isotropic substrate, at higher frequencies. The existence of this leaky mode has been confirmed both numerically and experimentally. This new mode exists independently of, and in addition to, the customary bound dominant mode. It leaks power away from the line into the fundamental TM/sub 0/ surface wave of the surrounding grounded substrate, and may therefore be responsible for spurious microstrip circuit performance at higher frequencies. This could have important implications for millimeter-wave circuits.

Abstract: Miniature microstrip stepped impedance resonator bandpass filters and diplexers for satellite mobile communications have been developed. A very high dielectric constant substrate (/spl epsiv//sub r/=89 and h=2 mm) is used. Experimental results show that an unloaded half wave resonator quality factor as high as 400 at 1.5 GHz, with such substrate, may be possible. The merit of this circuit lies in the simplicity of design procedure, the possibility of developing this filter with quite a variety of high dielectric constant substrate materials and the simplicity of simulation with most commercial software packages. A four resonator bandpass filter with 35 MHz bandwidth at 1.55 GHz was designed and implemented with this substrate. Based on this filter, a diplexer which meets satellite mobile communications performance has been developed. Experimental results are in good agreement with theoretical predictions.

Abstract: The results of a comprehensive investigation into the characteristics and optimization of inductors fabricated in the top-level metal of a sub-micron silicon VLSI process are presented. A computer program which extracts a physically-based model of microstrip components which is suitable for circuit (SPICE) simulation has been used to evaluate variations in metallization, layout geometry and substrate parameters upon inductor performance. 3-D numerical simulations and experimental measurements of inductors were also used to benchmark the model accuracy. It is shown in this work that low inductor Q is primarily due to the restrictions imposed by the thin interconnect metallization available in most VLSI technologies, and that computer optimization of the inductor layout can be used to achieve a 50% improvement in component Q-factor over unoptimized designs.

Abstract: A new fullwave global analysis of complex inhomogeneous structures including passive or active, linear or non linear lumped elements is presented. Only one electromagnetic simulation of the distributed part, by a 3D finite element method using edge elements, is needed corresponding to the insertion of several lumped elements placed at the same position. Results for a resistor, a diode inserted in a microstrip circuit as well as a Gunn diode amplifier are presented and comparisons with measurements are given for an active structure.

Abstract: This paper reports on the basic theory of operation and experimental results obtained from an electric field imaging system for planar microwave circuits that employs the method of modulated scattering with monolithically integrated probes. The low-cost system is capable of mapping the normal and tangential electric field intensities and electrical phase delays above reciprocal microwave circuits in the frequency range of 0.5-18 GHz with a spatial electric field resolution of better than 100 /spl mu/m. Monolithic probes incorporating silicon Schottky diodes integrated with electrically small dipole and monopole antenna scatterers on a 40-/spl mu/m-thick high-resistivity silicon substrate are used. Electric field intensity and electrical phase delay images are presented for a 55-/spl Omega/ coplanar waveguide line (CPW), a three-turn microstrip meander line at 8.8, 11.7, and 13.4 GHz, a microstrip coupled-line directional coupler at 10 GHz, and a microstrip patch antenna at 12.85 GHz. The results demonstrate that the modulated scattering technique is a valuable low-cost tool for microwave circuit diagnostics.

Abstract: A new type of microstrip to waveguide transition is presented, based on slot coupling and a dielectric quarter wave transformer. For a return loss of 20 dB, a relative bandwidth of 16% was achieved. The structure is compact, MMIC-compatible and can be made hermetic.

Abstract: A microstrip EMI shunt for an implantable medical device (e.g., an ICD) which includes a microstrip transmission line secured to an interior surface of a housing of the device, the microstrip transmission line having a first end secured to a connector wire which is electrically coupled to internal electronics of the device, and a second end which is open-circuited. The microstrip transmission line has a length nλ/4, where λ is the wavelength of EMI (in the microstrip medium) having a selected frequency f which is desired to be shunted, and n is an odd integer ≧1. In operation, EMI of the frequency f is shunted via the microstrip transmission line prior to reaching the internal electronics of the device. Additional microstrip transmission lines having appropriately chosen lengths to shunt EMI of different frequencies can also be provided.

Abstract: The paper presents a study of some elementary antennas, such as a dipole, a waveguide aperture, a microstrip patch, a spiral and a helix, when they are mounted on a ground plane with circular corrugations acting as a soft surface. The results of both experiments and calculations are described. The latter have been done either by the uniform geometrical theory of diffraction (UTD) or by the moment method (MM), and are in good agreement with the measurements. It is found that the corrugated soft ground plane makes the radiation patterns of all the antennas more rotationally symmetric with lower sidelobe levels and lower crosspolarisation when compared to using a smooth conducting ground plane.

Abstract: Microstrip reflectarrays utilize the advantages of planar antenna technology in providing an alternative to parabolic reflectors. The main barrier to implementing a microstrip reflectarray in many applications where reflectors have traditionally been used is that the gain bandwidth is typically only 5 percent (defined for a 1 dB drop from peak gain) for a microstrip reflectarray. Factors that limit reflectarray gain bandwidth are discussed. Reflectarrays can be designed with a prime focus feed, or an offset feed. Using a prime focus feed is the most straightforward approach, however this configuration results in aperture blockage effects. Also, in reflectarrays which are scanned off broadside, beam squint with frequency will occur for a prime focus feed. The offset feed is more attractive in that aperture blockage effects are minimized, at the expense of a slightly more complicated design and analysis procedure. A further advantage is that the effect of beam squint with frequency can be greatly minimized by choosing the correct offset position. In this paper a comparison of beam squint in prime focus and offset fed microstrip reflectarrays is investigated. A simple criterion for minimizing beam squint with frequency is presented, and results from an analysis of a linear reflectarray are discussed.

Abstract: A switchable microwave signal mixing circuit is disclosed which comprises: an osc 3 for generating an osc signal; 1st and 2nd microstrip lines 6, 7, coupled to the oscillator, for receiving 1st and 2nd microwave signals and the osc signal respectively; a bias voltage control circuit 54 for alternatively generating 1st and 2nd control bias voltages; 1st and 2nd FETs 8, 9, having 1st and 2nd gates supplied with the 1st and 2nd control bias voltages and coupled to the 1st and 2nd microstrip lines, drains supplied with bias voltages, and sources respectively, for alternatively generating 1st and 2nd IF signals from the 1st and 2nd microwave signals and the osc signal from the 1st and 2nd microstrip lines according to the control bias voltages; and an IF signal outputting circuit 14-18, 21 for outputting one of the IF signals selectively generated. In addition, a Wilkinson's divider 14-16 may be provided between the 1st and 2nd FETs and the outputting circuit for providing an isolation between the 1st and 2nd FETs. In addition, 1st and 2nd probing circuits 24, 25 coupled to the 1st and 2nd microstrip liens, for converting the 1st and 2nd microwaves into the 1st and 2nd microwave signals including 1st and 2nd TEM waves may be provided.

Abstract: A miniaturized Wilkinson power divider using three-dimensional (3-D) monolithic microwave integrated circuit (MMIC) technology is presented. The new power divider utilizes stacked thin film microstrip (TFMS) lines that sandwich a ground plane with a slit between the TFMS lines. The slit effectively widens the upper and lower TFMS-line widths, which makes it possible to stack high-impedance lines with a reasonable conductor strip width and lower loss. The proposed structure also exhibits a coupling between the quarter-wavelength conductor strips of less than -15 dB, simplifying the design for each TFMS line. A fabricated 15-25 GHz Wilkinson power divider, the area of which is only 0.31 mm/spl times/0.52 mm, exhibits a coupling of -4.5/spl plusmn/0.5 dB, isolation of greater than 15 dB, and a phase deviation of less than 3 degrees.