Showing papers on "Dielectric resonator antenna published in 2003"

Dielectric resonator type antennas

Abstract: The present invention relates to a dielectric resonator antenna comprising a block (10) of dielectric material of which a first face intended to be mounted on an earth plane is covered with a metallic layer (11). According to the invention, at least one second face perpendicular to the first face is covered with a partial metallic layer (12) having a width less than the width of this second face. The invention applies in particular to DRA antennas for domestic wireless networks.

Numerical analysis of stacked dielectric resonator antennas excited by a coaxial probe for wideband applications

Abstract: The objective of the present study is to improve the bandwidth of the dielectric resonator antenna (DRA) excited by a coaxial probe by using a stacked DRA configuration above an infinite ground plane. The DRA is axisymmetric and a coaxial probe is placed off the antenna axis to excite the HEM/sub 11/spl delta// mode in the DRA, resulting in a broadside radiation pattern. A surface integral equation formulation and the method of moments are used for the numerical analysis. The input impedance and the far field radiation patterns have been computed and the effects of different parameters on the antenna performance have been investigated. With the proper excitation and selection of the resonator parameters, a bandwidth of 35% has been achieved for the stacked DRA configuration based on a -10 dB reflection coefficient on a 50 /spl Omega/-transmission line. An equivalent circuit model is postulated to describe the dual-resonance behavior of the stacked antenna system.

Input/output coupling structure for dielectric waveguide resonator

Abstract: Disclosed is an input/output coupling structure for a dielectric waveguide resonator to be mounted on a printed circuit board, which comprises; a region defined in the printed circuit board and surrounded by a first conductive film formed on the front surface of the printed circuit board and connected to a microstrip line on the printed circuit board, a second conductive film formed on the back surface of the printed circuit board, and a conductive wall connecting the respective peripheries of the first and second conductive films; a first slot formed in the front surface of the region; and a second slot formed in a surface of the dielectric waveguide resonator which is disposed to be opposed to the region of the printed circuit board. The first and second slots are adapted to be disposed in opposed relation to one another. The coupling structure can achieve the connection between a dielectric waveguide resonator and a microstrip line without forming any input/output electrode on the resonator, to facilitate the application of the dielectric waveguide resonator to an electronic circuit even if it is intended to be used in millimetric-wave band.

Wide-band truncated tetrahedron dielectric resonator antenna excited by a coaxial probe

Abstract: A truncated tetrahedron dielectric resonator antenna is examined numerically and experimentally. The tetrahedron base is an equilateral triangular over a ground plane and excited by a coaxial probe to provide a broad side radiation pattern. Three different configurations are analyzed: the truncated tetrahedron when the wide base is attached to the ground plane, the narrow base attached to the ground plane, and the equitriangular cylinder. Results are verified experimentally and numerically. The tetrahedron with narrow base attached to the ground plane achieves wide-band performance for the impedance match and the radiation patterns of about 40%.

Isolated planar gyroscope with internal radial sensing and actuation

Abstract: The present invention discloses an inertial sensor comprising a planar mechanical resonator with embedded sensing and actuation for substantially in-plane vibration and having a central rigid support for the resonator. At least one excitation or torquer electrode is disposed within an interior of the resonator to excite in-plane vibration of the resonator and at least one sensing or pickoff electrode is disposed within the interior of the resonator for sensing the motion of the excited resonator. In one embodiment, the planar resonator includes a plurality of slots in an annular pattern; in another embodiment, the planar mechanical resonator comprises four masses; each embodiment having a simple degenerate pair of in-plane vibration modes.

Theory and experiment of circularly polarized dielectric resonator antenna with a parasitic patch

Abstract: The use of a single parasitic patch for circular polarization (CP) excitation of the dielectric resonator antenna (DRA) is investigated. For demonstration, the technique is applied to the conformal-strip fed hemispherical DRA, excited at the fundamental TE/sub 111/ mode. Using the Green's function approach, the integral equations for the conformal-strip and parasitic-patch currents are formulated by matching the appropriate boundary conditions. The equations are then solved using the method of moments (MoM). In using the MoM, both the rigorous and simplified current expansions are used for the parasitic patch, and their results are compared with each other. In each case, the impedance integrals are evaluated by virtue of newly obtained recurrence formulas and direct analytical integration. Hence, the results can be calculated very efficiently without the need for any numerical integration, which greatly facilitates the numerical implementation. The input impedance, axial ratio, and radiation patterns of the CP DRA are calculated, and the results are in good agreement with measurements.

Bulk acoustic wave resonator and circuit comprising same

Abstract: The invention relates to a resonator operating with bulk acoustic waves (BAW resonator, BAW=Bulk Acoustic Wave) and band-pass filters constructed of such resonators. To increase the edge steepness of the transmission band of a BAW band-pass filter, the invention proposes reducing the effective coupling of a BAW resonator by using the connection in parallel of a BAW resonator and a capacitor instead of only one resonator. In addition, to increase the edge steepness of the transmission band, the use of a connection of coupled BAW resonators in the serial branch of a filter circuit with another resonator or resonator stack in the parallel branch of the filter circuit is proposed, the additional resonator or resonator stack being connected to the center electrode of the resonator stack specified initially.

Method and apparatus for intracorporeal medical imaging using a self-tuned coil

Abstract: Disclosed herein is an RF probe for use with a medical imaging apparatus, the probe comprising an intracorporeal self-tuned resonator coil for receiving a signal indicative of an image of an interior portion of a body. The resonator coil is preferably coupled to a transmission medium having a characteristic impedance such that the resonator coil is substantially self-matching with the transmission medium's characteristic impedance. Preferably the resonator coil comprises an open wound conductor having a plurality of turns. The length of the resonator coil can be used to tune the resonator coil to a desired frequency, such as the Larmour frequency. Further, a return lead of the transmission medium is preferably coupled to an end of the conductor, and a signal lead of the transmission medium is preferably coupled to a point on the winding, thereby defining a turns ratio for the resonator coil. The turns ratio of the resonator coil can be used to match the resonator coil to the characteristic impedance of the transmission medium. Because the resonator coil of the present invention is self-tuning and self-matching, it avoids the use of bulky and relatively expensive tuning and matching circuits.

Dual-band power divider based on semiloop stepped-impedance resonators

Abstract: Presents a power-divider architecture whose characteristics are adjustable independently at two frequencies. The circuits uses a single semiloop stepped-impedance resonator filter coupled to the input and output lines. A specific methodology has been developed to design such a circuit.

An elliptic dielectric resonator antenna designed for circular polarization with single feed

Abstract: A single-fed elliptic dielectric resonator antenna is designed for circular polarization. The feed is a coaxial probe chosen with the proper parameters to achieve wideband matching and good circular polarization properties. The analysis is performed numerically using WIPL-D. The single-fed DRA achieves 3.5% circular polarization bandwidth and 14% matching bandwidth. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 454–456, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10948

Dielectric resonator antenna, a candidate for radar applications

Abstract: Dielectric resonator antennas (DRA) are newly developed antennas that are wideband, small size and have high radiation efficiency. An overview of the DRA is presented to show some of their characteristics, such as geometry, matching bandwidth, radiation patterns, etc. Radiation patterns for some arrays are presented for a linearly polarized linear phased array. The circularly polarized DRA in the array environment is discussed. Advantages of using DRA in the radar system are highlighted indicating that the DRA is an appropriate candidate for radar applications mainly because of high efficiency and wideband performance.

Adjusting the frequency of film bulk acoustic resonators

Abstract: A material may be removed from the top electrode of a film bulk acoustic resonator to alter the mass loading effect and to adjust the frequency of one film bulk acoustic resonator on a wafer relative to other resonators on the same wafer. Similarly, the piezoelectric layer or the bottom electrode may be selectively milled with a focused ion beam to trim the resonator.

Design of coupled resonator filters using admittance and scattering matrices

Abstract: The longitudinal coupling of thin film bulk acoustic resonator (FBAR) is investigated in order to design coupled resonator filter (CRF). Such devices are dedicated to high-frequency filter applications. A scattering matrix algorithm that was already used to simulate simple FBARs devices is used to study the behavior of these structures. The principle of the algorithm is recalled and is explained how it can be adapted to the simulation of multiport devices. Then an example of filter design is given.

Apparatus for adjusting the resonance frequency of a microelectromechanical (MEMS) resonator using tensile/compressive strain and applications thereof

Abstract: A method for varying the resonance frequency of a resonator beam is disclosed. The method comprises first manufacturing a resonator beam having a first end and a second end. The resonator beam is suspended above a substrate by the first end and the second end. At least one end of the resonator beam is connected to an actuator that applies an actuation force to the resonator beam to apply tensile strain or compressive strain onto said resonator beam. By varying the amount of actuation force, the resonance frequency of the resonator beam may be tuned. Additionally, by varying the magnitude and direction of the actuation force, the resonator beam may be used as a temperature sensor or a temperature compensated resonator.

Precise measurements of the complex permittivity of dielectric materials at microwave frequencies

Abstract: Overview of precise resonant measurement methods for complex permittivity determination of low and medium loss dielectrics is presented. The following techniques are discussed: split post dielectric resonator (SPDR), TE 0 1 1 resonator, TE 0 1 δ mode dielectric resonator, and whispering gallery mode resonators (WGMR). Applications of split post dielectric resonators (SPDR) for measurements of specific materials like ferroelectrics and thin laminar materials are highlighted. It is shown that TE 0 1 δ mode dielectric resonator technique is one of the most accurate for permittivity, dielectric loss tangent and thermal coefficients of permittivity measurements of low and medium loss dielectrics having arbitrary permittivity value. Precise measurements of low permittivity dielectrics require spurious modes analysis and proper choice of sample size and its aspect ratio. Conductor and radiation loss limits are discussed for open and closed whispering gallery mode resonators.

Shell-type micromechanical actuator and resonator

Abstract: Dome-shaped radio-frequency micromechanical resonators were fabricated by utilizing the buckling of a prestressed thin polysilicon film. The enhanced rigidity of the dome structure leads to a significant increase of its resonant frequency compared to a flat plate resonator. The shell-type geometry of the structure also provides an imbedded actuation mechanism. Significant out-of plane deflections are actuated by mechanical stress introduced within the plane of the shell. We demonstrate that thermomechanical stress generated by a focused laser beam, or microfabricated resistive heater, provides an effective and fast mechanism to operate the dome as an acoustic resonator in the radio-frequency range. All-optical operation of the shell resonator and an integrated approach are discussed.

Rectangular waveguide excitation of dielectric resonator antenna

Abstract: In this communication, the waveguide-fed dielectric resonator antenna (DRA) is proposed and investigated. The waveguide is terminated by a baffle ground plane in which a coupling slot is cut, and the DRA resides above the coupling slot. To enhance the coupling, a second DR is placed on the other side of the slot inside the waveguide. The measured return loss, radiation patterns, and antenna gain of this novel configuration are discussed in this paper.

Method and apparatus for modulating an optical beam with a ring resonator having a charge modulated region

Abstract: An apparatus and method for modulating an optical beam by modulating charge in ring resonator to modulate a resonance condition of the ring resonator. In one embodiment, an apparatus (101) according to embodiments of the present invention includes a ring resonator (107) having a resonance condition disposed in semiconductor material. An input optical waveguide (105) disposed in the semiconductor material is optically coupled to the ring resonator. An output optical waveguide (109) is disposed in the semiconductor material and is optically coupled to the ring resonator. A charge modulated region (121) is disposed in the ring resonator and the charge modulated region is adapted to be modulated to adjust a resonance condition of the ring resonator.

Transparent miniature dielectric resonator for electron paramagnetic resonance experiments

Abstract: A novel miniature (∼2×2×1 mm) dielectric resonator for X-band electron paramagnetic resonance experiments is presented The resonator is based on a single crystal of KTaO3, which is excited to its TE01δ resonance mode by means of a simple iris-screw coupling Several configurations of resonators are considered and discussed with respect to their filling factor, power conversion ratio, and optical excitation efficiency Our findings are presented in terms of both experimental and theoretical studies For small samples, the high filling factor of this resonator results in a signal increase by a factor of 140–800 (assuming nonsaturating conditions) as compared to a rectangular X-band cavity The high power conversion factor (∼40 G/W), should enable one to perform pulse experiments employing power amplifiers, with ∼100-fold less peak power used for rectangular cavities With an antireflective layer, the crystal’s transparency enables efficient laser illumination of the sample in light-induced experiments

Methods for forming a frequency bulk acoustic resonator with uniform frequency utilizing multiple trimming layers and structures formed thereby

Abstract: A method of forming a tuned resonator structure by first forming a base resonator structure that comprises a trimming layer on a resonator structure, wherein the trimming layer comprises at least one first low loss acoustic layer on the resonator structure, and at least one second low loss acoustic layer on the first low loss acoustic layer. Then, a “tuned” resonator structure is formed by measuring the frequency of the base resonator structure and removing the number of each of the two different low loss acoustic layers determined to be necessary to achieve the targeted frequency of the base resonator structure, thus improving the frequency control, reliability and performance of the resonating structure.

Piezoelectric resonator device having detuning layer sequence

Abstract: A resonator device includes a piezoelectric resonator having a detuning layer sequence arranged on the piezoelectric resonator. The detuning layer sequence includes at least a first layer having a high acoustic impedance and a second layer having a low acoustic impedance.

Micro-ring resonator

Abstract: A resonator structure is presented comprising a closed loop resonator waveguide having a width varying over the circumferential region of the resonator waveguide. The resonator structure can be used in various applications, such as optical filters, lasers, modulators, spectrum analyzers, wavelockers, interleave filters, and optical add drop multiplexers.

Resonator and component with hermetic encapsulation

Abstract: Proposed is a resonator which works with bulk acoustic waves and is based on a layer structure known in the art, which is arranged over a substrate. According to the invention, the total surface of the layer structure, including all resonators contained therein, is covered with a dielectric layer and a metal layer which together form an acoustic mirror, a low-k dielectric being used for the dielectric layer. The total-surface mirror offers broadband functionality over a suitable frequency range. The dielectric contained within the mirror acts as a sealing protective layer for the resonator or resonators.

Ladder-type filter, branching filter, and communication device

Abstract: In a ladder type filter, a first inductor is connected in series with a parallel resonator. A second inductor is connected in parallel to a series resonator. The resonant point of the parallel resonator having the first inductor connected in series and the anti-resonant point of the series resonator developed on the lower frequency side of the resonant point of the series resonator, caused by the second inductor connected in parallel, substantially coincide with each other.

Compact dielectric resonator antenna for WLAN applications

Abstract: A new dielectric resonator antenna (DRA) with reduced size for WLAN applications is presented. The proposed antenna consists of a rectangular dielectric resonator with partial vertical and horizontal metallisations which is coupled to a microstrip line through a rectangular aperture in the ground plane. A 9.6 reduction coefficient is obtained compared to the volume of an equivalent isolated DRA. An experimental 12% bandwidth is also achieved in spite of the compact size.

Packaged integrated antenna for circular and linear polarizations

Abstract: A high radiation efficiency antenna system in a package is achieved by the provision of a Dielectric Resonator Package. A Dielectric resonator package comprises a dielectric body of the package forming a dielectric resonator that resonates at radio frequency and a feed substrate having an upper and a lower surface, a feed structure formed on the upper surface of the feed substrate, and RF circuitry mounted on the lower surface of the feed substrate. The feed substrate is attached to the dielectric body of the package from the side of the feed structure.

Performance of planar four-element array of single-fed circularly polarized dielectric resonator antenna

Abstract: A single-fed circularly polarized dielectric resonator antenna is analyzed numerically. The element is a perturbed rectangular dielectric resonator excited by a coaxial probe and is used in a four-element planar array. Different arrangements and excitations for the elements are used to study their effect on the circular polarization bandwidth. The circular polarization (cp) bandwidth for the sequential rotation feeding is found to be the best method and the broadside radiation cp is frequency independent. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 381–384, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11066

Grating-outcoupled cavity resonator having uni-directional emission

Abstract: A grating-outcoupled microcavity disk resonator has whispering gallery modes existing in a nearly circular resonator. Light is outcoupled by providing a grating region in the plane of the grating-outcoupled microcavity disk resonator. The grating region provides an outcoupling or lass mechanism that symmetrically interacts with the clockwise and counterclockwise whispering gallery modes, thereby making the resonator capable of surface emission.

Method of temporarily adjusting the index of refraction of ring resonator with precision laser micromachining

Abstract: A tuned optical resonator having a substrate and an input waveguide and an optical resonator waveguide formed on the substrate The optical resonator waveguide has a resonant frequency, exhibits a first index of refraction, temporarily exhibits a second index of refraction responsive to application of laser energy, and temporarily resonates at the resonant frequency while the laser energy is being applied

Micromechanical resonator having short support beams

Abstract: The illustrative embodiment of the present invention is a vertical-mode, free-free beam resonator, and micromechanical circuits that include one or more such resonators. In accordance with the illustrative embodiment, the resonator comprises a movable beam that overlies a drive electrode. The movable beam is supported by a plurality of supports, the length of which is substantially less than one-quarter of a wavelength of the resonant frequency of the resonator.