Showing papers on "Microstrip published in 1993"

Analysis of a reflectarray antenna using microstrip patches of variable size

Abstract: Microstrip reflectarrays typically use tuning stubs on each element to adjust the phase of the reflected field. The authors describe a new approach in which the need for tuning stubs is eliminated and phase control is achieved simply by adjusting the resonant length of the patch elements. The advantages of this approach are described, as are a full-wave analysis technique for computing the phase of the reflected field as a function of patch size and a design curve giving the change in patch size for a desired reflected field phase shift.< >

Design of wideband circularly polarized aperture-coupled microstrip antennas

Abstract: Two variations of a novel feeding technique for a wideband circularly polarized aperture-coupled microstrip antenna are described. Prototype designs for wideband linearly polarized elements are first presented, and then used for circularly polarized designs. Techniques used for design of the feed network are detailed, for both series feed and parallel feed versions. Experimental results are shown for each antenna, and results for the two designs are compared. The impedance and axial ratio bandwidths for these antennas are among the best yet achieved for microstrip antenna elements. Several design variations are also discussed. >

Microstrip patch designs that do not excite surface waves

Abstract: Two variations of a circular microstrip patch design are presented which excite very little surface wave power. Both of the designs are based on the principle that a ring of magnetic current in a substrate (which models the patches) will not excite the dominant TM/sub 0/ surface wave if the radius of the ring is a particular critical value. Numerical results for radiation efficiency and radiated field strength from a ring of magnetic current are shown to verify this basic design principle. The proposed patch designs are chosen to have a radius equal to this critical value, while maintaining resonance at the design frequency. The designs excite very little surface-wave power, and thus have smoother radiation patterns when mounted on finite-size ground planes, due to reduced surface-wave diffraction. They also have reduced mutual coupling, due to the reduced surface-wave excitation. Measured results for radiation patterns and field strength within the substrate are presented to verify the theoretical concepts. >

Analysis of a wide radiating slot in the ground plane of a microstrip line

Abstract: An analysis of a wide rectangular radiating slot excited by a microstrip line is described Coupled integral equations are formulated to find the electric current distribution on the feed line and the electric field in the aperture The solution is based on the method of moments and using the space domain Sommerfeld-type Green's function The information about the input impedance or reflection coefficient is extracted from the electric current distribution on the microstrip line utilizing the matrix pencil technique The theoretical analysis is described and data are presented and compared with other theoretical and experimental results >

Broad-band uniplanar hybrid-ring and branch-line couplers

Abstract: Novel uniplanar 180 degrees and 190 degrees hybrids suitable for MIC and MMIC applications are described. The uniplanar crossover hybrid-ring coupler using a coplanar waveguide (CPW) and slotline provides substantially improved amplitude and phase characteristics over a broad bandwidth compared to conventional microstrip hybrid-ring couplers. Experimental results show that the new coupler has a bandwidth of more than one octave from 2 GHz to 4 GHz with a +or-0.4-dB power dividing balance and a +or-1 degrees phase balance. A uniplanar two-branch directional coupler using a coupled rectangular slotline ring has also been developed. CPW-to-slotline transitions using uniform and nonuniform CPWs or slotlines are also discussed. These transitions are uniplanar and simple to fabricate. No via-holes are needed for ground connections, and integration with solid-state devices is easy. A pair of broadband transitions using CPW shorts and slotline radial stubs is demonstrated with a 1-dB bandwidth of more than 5.2:1. >

Non-destructive characterization of materials by evanescent microwaves

Abstract: A microstrip quarter wavelength ( lambda g/4) resonator in conjunction with a small probe is used to resolve objects with characteristic dimensions as small as a thousandth of the wavelength ( lambda g/1000). The characteristic length for the decay of the evanescent waves at the tip of the probe was measured to be approximately 100-150 mu m at a microwave frequency of 1 GHz ( lambda free approximately=30 cm). The authors applied this technique to map microwave conductivity of metallic lines on glass and printed circuit boards and to investigate conductivity variations across a silicon wafer. It was possible to detect holes in printed circuit boards that were covered with solder and were not detectable otherwise.

High performance direct coupled bandpass filters on coplanar waveguide

Abstract: This paper describes the design and performance of shunt inductively coupled bandpass filters implemented on an open coplanar waveguide. This new structure exhibits low radiation loss due to the removal of the capacitively coupled gaps encountered in end or edge coupled filters. Unloaded Qs greater than 540 have been achieved in unshielded single section resonators at 4 GHz on very thin substrates. These high Qs enable the design of filters with low insertion loss and good stopband rejection. Applications include low insertion loss, high and printed filters where no screening is required, low noise oscillators and superconducting filters. >

Aperture fed rectangular and triangular dielectric resonators for use as magnetic dipole antennas

Abstract: The Letter reports the results of investigations on aperture-fed rectangular and triangular shaped dielectric resonators for use as magnetic-dipole antenna elements. Measured results show that both antennas have a large bandwidth (>10%) and their far field patterns are similar to that of a magnetic dipole.

Modeling and analysis of vias in multilayered integrated circuits

Abstract: A method for modeling and analyzing vias the multilayered integrated circuits is presented. The model is based on microwave network theory. The whole via structure is divided into cascaded subnetworks, including a vertical via passing through different layers and transitions from the microstrip line and/or striplines to the vertical via. The parameters of each subnetwork are obtained from electromagnetic field analysis. Numerical results in the frequency domain and the time domain are presented. Validation of the model has been carried out by both measurements and finite-difference-time-domain (FDTD) modeling. The results show good agreement with the measurements in the frequency range for which the components of the experimental model are within specification. The time domain simulation results also agree well with the FDTD results. >

Multiple band antenna

Abstract: An antenna for reception of signals in a plurality of frequency bands employed in portable and vehicular communications is constructed of a dielectric layer disposed on a metallic plate which serves as a ground plane. Microstrip antenna elements in the form of a planar radiator encircled by a loop radiator are disposed upon the dielectric layer. A rod radiator oriented normally to the plate extends through the patch radiator and the dielectric layer, and is surrounded by a dielectric cylinder which insulates the rod radiator from the planar radiator and the plate. The planar radiator may be configured as a patch radiator, a spiral radiator, or a crossed dipole radiator. Also, one or more additional layers of patch radiator elements may stacked upon the patch radiator to provide a stacked microstrip radiator. Terminals are positioned about the planar radiator for extracting orthogonal components of a circularly polarized electromagnetic signal. All radiators are smaller than approximately one-half wavelength of the shortest wavelength signal to be received by the antenna. The antenna is useful for receiving vehicular signals such as telephony, keyless door lock operation, ground positioning satellite signals, as well as AM/FM radio.

A fiber chromatic dispersion compensation technique with an optical SSB transmission in optical homodyne detection systems

Abstract: A fiber chromatic dispersion compensation technique with optical single-sideband (SSB) transmission in optical homodyne detection systems is described. The chromatic dispersion compensation technique is demonstrated in a 6-Gb/s SSB phase-shift-keying (PSK) homodyne detection system equivalent experiment. A 270-km conventional single-mode fiber is used as a transmission medium at 1.55 mu m, and a microstrip line is used as a delay equalizer. The effect of compensating for the chromatic dispersion with the microstrip line is verified by improvement of eye-opening. >

Transmission characteristics of finite-width conductor-backed coplanar waveguide

Abstract: This paper presents theoretical and experimental results for a finite-width conductor-backed coplanar waveguide (FW-CBCPW). The guiding characteristics of FW-CBCPW are investigated first by the rigorous method of mode matching. An FW-CBCPW through line is then placed within a test fixture commonly used in laboratories, and the scattering parameters of the through line are obtained theoretically by approximating the FW-CBCPW as a simple system of coupled transmission lines. Experimental results are shown to agree very well with the theoretical ones. In particular, the anomalous behavior observed in the transmission characteristic of the through line is related to the resonant phenomenon of the terminated side planes which are short-circuited at both input and output ends due to the test fixture. Finally, a technique of mode suppression in the side-plane regions is suggested for the improvement of signal transmission over a broad band of frequency spectrum. The effects of extra higher order modes on the transmission characteristics at high frequencies are also discussed. >

Mode Analysis and Stabilization of a Spatial Power Combining Array with Strongly

Abstract: In order to attain stabilized power-combining opera- tions of a strongly coupled active antenna array, mode analysis for the multi-moding problem of the array is presented, and an effective method for exciting only the in-phase power-combining mode is proposed. In a one-dimensional array of active antennas coupled mutually through microstrip lines, the frequencies and the voltage distributions of the normal modes are obtained. Stable modes of the array are identified using the averaged potential theory. Time evolutions of the mode amplitudes are also calculated. In order for only the desired power-combining mode to oscillate, appropriate resistors are introduced at the midpoints of the coupling lines between the active antennas. An experiment for the arrays with up to eight active antennas has been carried out using Gunn diodes. It has been confirmed that the introduction of the resistors is effective for stable excitation of the in-phase power-combining mode.

Analysis of finite phase arrays of microstrip patches

Abstract: A method for the analysis of large phased arrays of microstrip patches is presented. It is based on an infinite array approach where the edge effects are taken into account through the convolution with a proper window function. In the first step, a rigorous Green's function corresponding to a finite array of elementary sources is derived. This Green's function is then used to analyze the finite phased array of microstrip patches. Results are shown for the active impedance and element patterns of several arrays, and compared with measurements or, in the case of small arrays, with results obtained by a rigorous element-by-element approach. It is shown that the method, even if developed for the analysis of large arrays, is able to handle small arrays. Indeed, the results obtained are good even for single patches. Although the method has been developed for the microstrip phased array case, the results are general and are valid for any phased array with a rectangular grid. >

Identification of propagation regimes on integrated microstrip transmission lines

Abstract: There has been a resurgence of interest in the propagation characteristics of open integrated microstrip transmission lines. This is due in part to the discovery of diverse propagation regimes for higher-order modes on open lines. In contrast to the dominant EH/sub 0/ mode, three distinct propagation regimes exist for higher-order modes on microstrip transmission lines. In this paper, a rigorous spectral-domain integral equation formulation is used to analyze propagation in all three regimes. This formulation provides a clear physical picture of the different propagation regimes based on the mathematical location of poles and branch points in the complex spectral-variable plane. As an illustration, the formulation is applied to the case of an isolated uniform microstrip transmission line. The integral equation is discretized via the method of moments, and entire-domain basis functions incorporating suitable edge behavior are utilized to provide convergence with relatively few terms. The results obtained are compared to the results of other workers, and good agreement is observed. >

Tuning of microstrip antenna on ferrite substrate

Abstract: The permeability variation of a ferrite substrate with an axial DC magnetic bias field along with the RF excitation of a microstrip antenna leads to multiresonant behavior. A study of tuning the patch antenna on a ferrite substrate to exploit this feature is reported, along with the associated theoretical analysis and experimental findings. >

Transmission of single-flux-quantum pulses along superconducting microstrip lines

Abstract: The authors analyzed, designed, and tested drivers and receivers which make it possible to connect distant circuits of the rapid single-flux-quantum (RSFQ) logic/memory family by passive superconducting microstrip lines Using these circuits implemented with a niobium trilayer fabrication technology, reliable transmission and reception of the SFQ pulses over distances up to 1 cm, with margins of bias currents as wide as +or-30%, have been demonstrated The pulses can be passed along wide lines (20 mu m for 35 mu Nb-Al/sub 2/O/sub 3/-Nb Josephson junction technology) over such distances and can be picked up by the RSFQ receiver >

A new compact wideband balun

Abstract: A novel wideband balun has been developed for MMIC (monolithic microwave integrated circuit) applications Simple RF reflection and coupling principles are used to achieve a wideband performance in a simple microstrip configuration The design was intended for 8- to 18-GHz wideband mixer applications According to the predicted performance the insertion loss was better than 2 dB from 7 to 19 GHz, the amplitude balance was less than 1 dB, and the phase balance was less than 5 degrees from the 180 degrees phase difference Experimental results show very good agreement with the predicted performance >

Mode analysis and stabilization of a spatial power combining array with strongly coupled oscillators

Abstract: In order to attain stabilized power-combining operation of a strongly coupled active antenna array, a mode analysis for the multimoding array problem is presented, and an effective method for exciting only the in-phase power-combining mode is proposed. In a one-dimensional array of active antennas coupled mutually through microstrip lines, the frequencies and the voltage distributions of the normal modes are obtained. Stable modes of the array are identified using the averaged potential theory. Time evolutions of the mode amplitudes are also calculated. In order for only the desired power-combining mode to oscillate, appropriate resistors are introduced at the midpoints of the coupling lines between the active antennas. An experiment for arrays with up to eight active antennas has been carried using Gunn diodes. It has been confirmed that the introduction of the resistors is effective for stable excitation of the in-phase power-combining mode. >

High frequency ceramic multi-layer substrate

Abstract: A high frequency ceramic multi-layer substrate includes a stripline (1) embedded between two dielectric layers (2,2') having ground electrodes (3,4) at the top surface and at the bottom surface thereof and an electric circuit formed on another dielectric layer (5) applied to one of the ground electrodes. The stripline is connected to the electric circuit through via holes (6,6') provided through the dielectric layers. The equivalent length from the stripline to the electric circuit is a fourth of the wavelength of an input high frequency signal, to result in high frequency attenuation circuit. Another high frequency ceramic multi-layer substrate includes further another electrode provided via another dielectric layer of larger dielectric constant to form a capacitor with one of the ground electrodes, and a further dielectric layer for forming an electric circuit thereon is applied to the electrode. The stripline is connected to the electric circuit through via holes provided through dielectric layers. The electric circuit may be an impedance matching circuit of the stripline or a direct current bias circuit (8). This multi-layer structure makes the high frequency substrate compact and improves high frequency characteristics.

Waveguide to microstrip conversion means in a satellite broadcasting adaptor

Abstract: A waveguide to microstrip converter allowing size reduction as well as providing good cross polar discrimination and input VSWR characteristic. The waveguide to microstrip converter includes a structure of an orthogonal transducer formed of a circular waveguide and a rectangular waveguide integrally formed with and orthogonal to the circular waveguide. A first probe and a second probe are respectively coupled to the circular waveguide and rectangular waveguide. An output terminal of the first probe and an output terminal of the second probe are formed on the same plane and connected to respective microstrip lines.

Superconducting microstrip antennas: an experimental comparison of two feeding methods

Abstract: The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gas-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals. >

Research on planar antennas and arrays: 'structures Rayonnantes'

Abstract: The basic research on radiowave systems dealing with electromagnetism, electronics, and signal processing at the University of Rennes is discussed. The fusion of these different domains occurs for studies concerning systems where radiating structures, active devices and interfaces, and signal processing play a fundamental role and cannot be separated. Different geometries and methods developed for various types of patches, dipoles, and slot antennas, including patch antennas with coaxial or microstrip feeds, printed slot antennas, slot-fed patches, slot-loaded patches, and electromagnetic coupled dipoles and patches, are described. Different kinds of arrays have been designed with active or passive feed networks. The analysis includes mutual-coupling effects, especially when beam steering is considered with small element spacing. Arrays considered include planar phased arrays, planar passive arrays, dual-beam printed antennas, and arrays of microstrip dipoles. >

Micromachined circuits for millimeter- and sub-millimeter-wave applications

Abstract: Two approaches for the development of micromachined circuits for millimeter- and submillimeter-wave applications are discussed. These technologies provide a means to overcome the drawbacks typically associated with conventional planar transmission lines, such as microstrip and coplanar waveguides. Examples demonstrating the use of micromachining to effectively incorporate a third dimension into the geometry of monolithic circuits are presented. This introduces additional parameters in the design and results in structures with superior electrical performance, such as membrane-supported circuits, and reduced volume and weight, such as micromachined-shielded circuits. Micromachined circuits which incorporate miniaturized shielding packages in a monolithic design are described. The performance of these circuits shows that the low-volume, low-weight packaging is effective in reducing signal loss, without degrading the desired frequency response. >

Resonance in a superstrate-loaded cylindrical-rectangular microstrip structure

Abstract: The complex resonant frequencies of the cylindrical-rectangular microstrip structure loaded with a dielectric superstrate layer is studied using a rigorous full-wave analysis, and the numerical results are obtained using the Galerkin moment method calculation. The numerical convergence for the selected sinusoidal basis functions with and without the edge singularity condition is also discussed. Numerical results for the dependence of the real and imaginary parts of the complex resonant frequencies on the superstrate permittivity and thickness are calculated and analyzed, and are compared with those obtained for the planar microstrip structure. >

Resonance of a rectangular microstrip patch on a uniaxial substrate

Abstract: Effects of uniaxial anisotropy in the substrate on the complex resonant frequency of the microstrip patch antenna are investigated in terms of an integral equation formulation. The complex resonant frequency of the microstrip patch antenna is calculated using Galerkin's method to solve the integral equation. The sinusoidal functions that are selected as the basis functions, which show fast numerical convergence. Numerical results indicate that both the resonant frequency and the half-power bandwidth are increased due to positive uniaxial anisotropy and decreased due to negative uniaxial anisotropy. >

Superconducting millimeter wave oscillators and SIS mixers integrated on a chip

Abstract: All-refractory material superconducting millimeter-wave oscillators have been designed and investigated experimentally with different superconductor-insulator-superconductor (SIS) mixers integrated on the same chip. Tested structures include a flux-flow oscillator (FFO) based on a long Josephson junction, a coupling section, and an SIS detector with tuned out junction capacitance. Coupling sections were designed as multistep microstrip quarter-wave impedance transformers. All junctions have been fabricated on the basis of a high-quality trilayer Nb-AlO/sub x/-Nb process. Microwave oscillations in the frequency range 75-500 GHz have been detected experimentally. The level of delivered power was estimated from the pumped I-V curve of the strongly coupled single junction detector. Coupled power levels higher than 0.1 mu W at 256 GHz were achieved. A spectral linewidth of the FFO of less than 1 MHz has been estimated experimentally. The first attempt to create an integrated receiver based on an FFO and an SIS array mixer integrated on the same chip was made in the 2-mm wavelength band. >

Print dipole antenna

Abstract: PURPOSE:To realize the print dipole antenna having a wider band characteristic. CONSTITUTION:The above antenna is provided with dipole antennas 1a, 1b, a parallel 2-wire 2, taper lines 3a, 3b, and microstrip lines 4a, 4b. The system is added with a matching circuit 7 whose characteristic is adjusted to obtain a desired band width and comprising one or plural open stubs 6a, 6b when viewing the dipole antenna 1 from input terminal of the microstrip line 4. Thus, a reflection quantity is reduced and the wider band characteristic is provided.

Comparison of three series fed microstrip array geometries

Abstract: The authors describe three different design approaches for series-fed broadside microstrip arrays having a center feed point. The first array uses a standard standing-wave feed design, but with the novel feature that the patch width is varied in order to obtain the desired amplitude taper. The second design also uses patches of varying widths, but the main feed line is designed to be matched at each patch tap point. The third array uses a center-fed feed network with each half of the array designed as a traveling-wave array with a main beam angle slightly off broadside. As a comparative example, the authors have designed and tested a 16-element array with a 22-dB sidelobe level for each of the above designs. Patterns, bandwidth, gain, and directivity have been compared for the three designs. >

Microstrip circuit design using neural networks

Abstract: A novel technique that uses neural networks to efficiently design microstrip circuits is presented. A full-wave analysis is employed to rigorously characterize a microstrip circuit, which results in a finite set of pairs of input and output parameter vectors. The neurons, arranged as a three-layer network, are used to learn the mappings from input to output and then give accurate approximations for the output vectors at any arbitrary input. It is emphasized that a three-layer neural network is capable of performing any mapping if the right connections among the neurons can be made. A real example involving microstrip corporate feed design is given to illustrate the potential power of this technique. >