Showing papers on "Dielectric resonator antenna published in 2000"

Dual band wideband adjustable antenna assembly

Abstract: A dual frequency wideband antenna assembly for use in a wireless communication device (22). The antenna assembly having a first resonator element (52) disposed away from the ground plane element (28), said first resonator element being operatively coupled at a first location (40) to the ground plane and being operatively coupled at a second location (42) to the RF signal port; a second resonator element (54) disposed away from the ground plane. The first and second resonator elements are coupled via a bridge conductor (56) and a capacitive tuning network (71). The capacitive tuning network may include a discrete capacitor or an adjustable capacitor which varies in response to a signal.

High quality-factor tunable resonator

Abstract: A high quality-factor, tunable radio frequency or microwave resonator is disclosed. The resonator includes one or more microelectromechanical switches positioned along its length. The switches are comprised of metal membrane bridges spanning the microstrip resonator. The bridges are connected to radial stubs that comprise reactive loads. An electrostatic potential differential between the bridge and microstrip resonator causes the bridge to collapse, thereby coupling a radial stub to the microstrip. The imposition of the reactive loads on the resonator causes the resonant frequency to change. Multiple resonators employed in a filter configuration can be variably coupled using microelectromechanical bridges that engage or disengage capacitive air gaps between two microstrip lines, to control filter bandwidth over wide tuning ranges.

Design and analysis of multisegment dielectric resonator antennas

Abstract: The multisegment dielectric resonator antenna (SDRA) has previously been developed to significantly enhance the coupling to a microstrip line. The MSDRA greatly facilitates the integration with a printed feed distribution network for use in a large array environment. The thickness and permittivity of the dielectric insert of the MSDRA can be adjusted to match the element impedance to that of the feed line. A detailed study of the effects of varying the dielectric insert parameters was carried out and useful guidelines are presented for the design of MSDRAs.

Resonator structure and a filter comprising such a resonator structure

Abstract: A resonator structure (1200, 1300, 1400), where a certain wave mode is piezoelectrically excitable, comprises at least two conductor layers (110, 120) and at least one piezoelectric layer (110) in between the conductor layers, said conductor layers and piezoelectric layer extending over a first area of the resonator structure, which first area is a piezoelectrically excitable area of the resonator structure. The resonator structure is characterized in that it comprises a frame-like zone (2, 4) confining a center area (3) within the first area, a cut-off frequency of the piezoelectrically excited wave mode in the layer structure of the frame-like zone is different from that in the layer structure of the center area, and width of the frame-like zone and acoustical properties of the layer structure in the frame-like zone are arranged so that displacement relating to the piezoelectrically excited strongest resonance mode is substantially uniform in the center area of the resonator.

Coaxial dielectric rod antenna

Abstract: An antenna. The antenna (20) includes a first dielectric antenna rod having a first dielectric constant (e3). The first dielectric antenna rod (22) is coupled to a first frequency transmission source (27) for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant (e1). A second dielectric antenna rod (24) is provided having a second dielectric constant (e2). The second dielectric antenna rod is coupled to a second frequency transmission source (28) for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Steerable-beam multiple-feed dielectric resonator antenna of various cross-sections

Abstract: A radiating antenna capable of generating or receiving radiation using a plurality of feeds and a dielectric resonator of various cross-sections is disclosed. The purpose of using multiple feeds with a single dielectric resonator antenna is to produce several beams each having a 'boresight' in a different direction. Several such beams may be excited simultaneously to form a new beam in any arbitrary direction. The new beam may be incrementally or continuously steerable and may be steered through a complete 360 degree circle. The invention may be combined with an internal or external monopole antenna so as to cancel out the antenna backlobe or otherwise resolve the front/back ambiguity that arises with this type of dielectric resonance antenna.

Conformal strip excitation of dielectric resonator antenna

Abstract: A new excitation scheme that employs a conducting conformal strip is proposed for dielectric resonator antenna (DRA) excitation. The new excitation scheme is successfully demonstrated by using a hemispherical DRA whose exact Green function is found using the mode-matching method. The moment method is used to solve the unknown strip current from which the input impedance is obtained. Novel recurrence formulas were obtained so that the impedance integrals are evaluated analytically. This solves the singularity problem of the Green function and substantially reduces the computation time. An experiment was carried out to verify the theory. The co- and cross-polarized field patterns are also shown. In addition, an experimental technique which deals with the problem of an air gap between the DRA and the ground plane is presented.

Circular-polarised dielectric resonator antenna excited by dual conformal strips

Abstract: A circular-polarised cylindrical dielectric resonator antenna excited by dual conformal strips is investigated experimentally. The configuration offers a wide axial-ratio bandwidth of 20%. We measured axial ratio, radiation patterns and antenna gain of the configuration are presented and discussed.

Light modulation in whispering-gallery-mode resonators

Abstract: Techniques to modulate light by using a whispering gallery mode optical resonator. The light modulator uses an optical coupler (121) to input an optical beam (104), from a laser (102), into a wispering gallery mode resonator formed of an Electro-Optic material (110). An electronic driving circuit (140) is coupled to supply the electrical wave to the electrical coupler (130). A control signal (150) can be fed into the circuit (140) to modulate the electrical wave. This modulation is then transferred to the output coupler (122) which provides a modulated optical output (124).

Dielectric waveguide resonator, dielectric waveguide filter, and method of adjusting the characteristics thereof

Abstract: A conducting film is formed on a dielectric block in a dielectric waveguide resonator, and a through-hole is formed in the dielectric block. The unloaded Q is set by selecting the outside dimensions of the dielectric block. The resonance frequency is set by selecting the size and location of the through-hole as well as the outside dimensions of the dielectric block. A terminal electrode is formed on the outer surface of the dielectric block. A coupling hole is formed in the dielectric block and a coupling electrode is formed on the inner surface of the coupling hole. One end of the coupling electrode is connected to the terminal electrode and the other end of the coupling electrode is either connected to the conducting film formed on the outer surface of the dielectric block or terminated inside the dielectric block. The above structure allows an increase in the degree of freedom in the design of the characteristics including the resonance frequency and unloaded Q of the dielectric waveguide resonator. The invention also provides a dielectric waveguide filter with a simple coupling mechanism whereby it is possible to couple to an external circuit without having to use an additional member and without electromagnetic leakage.

Encapsulated packaging for thin-film resonators and thin-film resonator-based filters having a piezoelectric resonator between two acoustic reflectors

Abstract: An acoustic reflector ( 48 ) is applied over a thin-film piezoelectric resonator ( 41, 61 ) which is supported on a semiconductor or semiconductor-compatible substrate ( 42, 62 ) of a microelectronic device ( 40, 60 ), enabling an encapsulant ( 49 ) to be applied over the reflector-covered resonator without acoustically damping the resonator. In one embodiment, alternating high and low acoustic impedance layers ( 51, 53 . . . 55 ) of one-quarter wavelength thicknesses constructively reflect the resonating wavelength to make an encapsulant in the form of an inexpensive plastic molding compound appear as a “clamping” surface to a resonator ( 41 ) peripherally supported over an opening ( 43 ) on a silicon substrate ( 42 ). In another embodiment, an encapsulant- and reflector-covered resonator ( 61 ) is mechanically supported above a second reflector ( 68 ) which eliminates the need for peripheral support, making substrate ( 68 ) also appear as a clamping surface. The invention enables low cost plastic packaging of resonators and associated circuitry on a single monolithic structure. A radio frequency transceiver front-end application is given as an exemplary implementation.

Dual polarization slot antenna assembly

Abstract: The invention discloses a slot antenna assembly for a wireless communications device having a printed wiring board element defining at least a ground plane and an input/output RF connection point. The antenna assembly further includes a dielectric element having a pair of opposed major surfaces; a conductive feed circuit disposed upon one of the major surfaces, said feed circuit coupled to the RF connection point of the printed wiring board; and a resonator circuit including a pair of resonator arms oriented approximately parallel to each other, said pair of resonator arms being coupled together via a conductive connection and defining a substantially elongate slot, one of said pair of resonator arms being conductively coupled to the feed circuit, and the other of said pair of resonator arms being conductively coupled to the ground plane of the printed wiring board. The slot antenna according to the present invention may be disposed within an associated wireless communications device relative to a ground plane element of a printed wiring board, or may be disposed separately away from the associated wireless communications device.

Device including a micromechanical resonator having an operating frequency and method of extending same

Abstract: A flexural-mode, micromechanical resonator utilizing a non-intrusive support structure to achieve measured Q's as high as 8,400 at VHF frequencies from 30-90 MHz is manufactured using polysilicon surface micromachining technology. Also, a method for extending the operating frequency of the resonator as well as other types of micromechanical resonators is disclosed. One embodiment of the method is called a differential-signaling technique. The other embodiment of the method is called a dimple-down technique. The support structure includes one or more torsional-mode support springs (16) in the form of beams that effectively isolate a resonator beam from its anchors (18) via quarter-wavelength impedance transformations, minimizing anchor dissipation and allowing the resonator to achieve high Q with high stiffness in the VHF frequency range. The resonator also includes one or more spacers (26) in the form of dimples formed on the flexural resonator beam (12) or the substrate. In operation, the dimples (26) determine a capacitive-transducer gap of the resonator. When a large DC-bias voltage is applied between a drive electrode (20) and the resonator beam (12), the dimples (26) provide a predetermined minimum distance between the flexural resonator beam (12) and the drive electrode (20).

Localized thermal tuning of ring resonators

Abstract: A thermally tunable resonator includes a resonator body having a resonance wavelength which changes as a function of temperature, a trench formed inside the resonator body, and a disk formed inside the trench and which is made from semiconductor layers, the layers being doped to form a forward biased junction. A first electrode, which does not cover the resonator body, is located atop the disk and in electrical contact with the forward biased junction, and a second electrode is located beneath and in electrical contact with the forward biased junction. When current is applied through the electrodes, heat is generated, changing the resonator body's resonance wavelength. Another thermally tunable resonator has a resonator body and heater in which two contact pads are electrically connected to a resistance above the resonator body. When current is applied to the resistance, heat is generated, changing the resonator body's resonance wavelength. A temperature sensor can be used to sense the resonator body's temperature.

Circularly polarized circular sector dielectric resonator antenna

Abstract: A circular sector dielectric resonator antenna (DRA) with circular polarization and a single feed is investigated and demonstrated The design utilizes the radius to height ratio and feed position of the circular sector DRA to excite two resonant modes that are spatially orthogonal in polarization and in phase quadrature Experimental results are provided for the design and these demonstrate that the circular sector DRA produces circular polarized radiation with axial ratio less than 3 dB over a 10% bandwidth

Electronic tunable filters with dielectric varactors

Abstract: A radio frequency electronic filter includes an input, an output, and first and second resonators coupled to the input and the output, with the first resonator including a first voltage tunable dielectric varactor and the second resonator including a second voltage tunable dielectric varactor. The resonators can include a lumped element resonator, a ceramic resonator, or a microstrip resonator. Additional voltage tunable dielectric varactors can be connected between the input and the first resonator and between the second resonator and the output. Voltage tunable dielectric varactors can also be connected between the first and second resonators.

Temperature compensation mechanism for a micromechanical ring resonator

Abstract: There is described a time base comprising a resonator (4) and an integrated electronic circuit (3) for driving the resonator into oscillation and for producing, in response to the oscillation, a signal having a determined frequency. The resonator is an integrated micromechanical ring resonator supported above a substrate (2) and adapted to oscillate around an axis of rotation (O) substantially perpendicular to the substrate, the ring resonator comprising a central post (5) extending from the substrate along the axis of rotation, a free-standing oscillating structure (6) connected to the central post and including an outer ring (60) coaxial with the axis of rotation and connected to the central post by means of a plurality of spring elements (62), and electrode structures (9; 9*) disposed around the outer ring and connected to the integrated electronic circuit. The free-standing oscillating structure further comprises a plurality of thermally compensating members (65) which are adapted to alter a mass moment of inertia of the free-standing oscillating structure as a function of temperature so as to compensate for the effect of temperature on the resonant frequency of the ring resonator.

Electronic part, dielectric resonator, dielectric filter, duplexer, and communication device comprised of high TC superconductor

Abstract: In a dielectric resonator, a superconductor is formed on two neighboring surfaces of a cubic dielectric body, and the superconductors formed on each two neighboring surfaces are connected by a silver electrode formed in the vicinity of the edge where the neighboring two surfaces join.

A Ka-Band Dielectric Resonator Antenna Reflectarray

Abstract: A reflectarray that uses a Dielectric Resonator Antenna (DRA) as the radiating element has been developed at Ka-Band. A variable length DRA provides the required phase shift at each cell on the reflectarray surface. Experimental results for this configuration show a similar performance to reflectarrays based on microstrip patch antennas.

Dielectric-patch resonator antenna

Abstract: A dielectric-patch resonator antenna having a resonator formed from a dielectric material mounted on a ground plane with a conductive skirt, and a patch element disposed inbetween. The ground plane and patch are formed from conductive materials. First and second probes are electrically coupled to the resonator for providing first and second signals, respectively, to or receiving from the resonator. The first and second probes are spaced apart from each other. The first and second probes are formed of conductive strips that are electrically connected to the perimeter of the resonator and are substantially orthogonal with respect to the ground plane. A dual band antenna can be constructed by positioning and connecting two dielectric resonator antennas together. Each resonator in the dual band configuration resonates at a particular frequency, thereby providing dual band operation. The resonators can be positioned either side by side or vertically.

Optical resonator microsphere sensor with altering Q-factor

Abstract: An optically based resonating sensor useful for detecting and discriminating specified substances present in the environment is provided. The resonating sensor comprises a light source and a coupler adapted to allow light to pass from the light source to a resonator wherein the light is stored for a specified period of time. The resonator is coupled to the coupler such that some portion of the light passing through the coupler enters the resonator and some portion of the light resonating within the resonator exits the resonator to the coupler. The outer surface of the resonator is modified such that the interaction of the modified outer surface of the resonator with a specified substance in the environment alters some characteristic of the light flowing through the sensor system. A detector is arranged to observe and detect the interactions between the modified outer surface and the light flowing through the system.

Resonator structure embedded in mechanical structure

Abstract: An assembly for supporting a substrate of an integrated circuit and forming a cavity resonator with the substrate. The assembly includes a baseplate in which a cavity for the cavity resonator is integrally formed. A substrate is mounted over the cavity resonator in the baseplate and an excitation coupling extends into the cavity of the cavity resonator.

Optical routing/switching based on control of waveguide-ring resonator coupling

Abstract: An optical wave power control device and method enables signal control, such as modulation and switching, to be effected with the application of very low power to a controller which is in optical communication with a recirculating mode resonator (200) and an optical propagation element. The propagation element is in power communication with a high-Q volumetric resonator. Power of a chosen resonant wavelength is coupled into the resonator, where it circulates with very low loss and returns to the propagation element. By applying a control signal into the controller, the propagated power can be varied between substantially full and substantially zero amplitudes. Loss factors can be maintained such that the resonator is overcoupled (i.e. parasitic losses are less than coupling losses). A critical coupling condition can be induced by a small swing in the controller, causing a disproportionate change in the output optical signal. The controller is preferably embodied in an interferometer (116) in the optical path of the resonator, and the control signal can be an applied voltage, current, or optical signal.

Broadband coaxial cavity resonator for complex permittivity measurements of liquids

Abstract: A novel cavity perturbation technique using coaxial cavity resonators for the measurement of complex permittivity of liquids is presented. The method employs two types of resonators (Resonator I and Resonator II). Resonator I operates in the frequency range 600 MHz-7 GHz and resonator II operates in the frequency range 4 GHz-14 GHz. The introduction of the capillary tube filled with the sample liquid into the coaxial resonator causes shifts in the resonance frequency and loaded Q-factor of the resonator. The shifts in the resonance frequency and loaded Q-factor are used to determine the real and imaginary parts of the complex permittivity of the sample liquid, respectively. Using this technique, the dielectric parameters of water and nitrobenzene are measured. The results are compared with those obtained using other standard methods. The sources of errors are analyzed.

Analysis of resonator eigenmodes in symmetric quasi-stadium laser diodes

Abstract: Resonator eigenmodes in symmetric quasi-stadium laser diodes consisting of two curved end-mirrors and two straight side-wall mirrors are theoretically studied. We obtained the resonator eigenmodes under typical resonator conditions, namely, a concentric and a near-concentric resonator conditions, a confocal resonator condition, and a geometrically unstable resonator condition. We used the extended Fox-Li mode calculation method which includes the effect of the total internal reflection at the side-wall mirrors. Unique resonator eigenmodes are obtained. Under the concentric and the near-concentric resonator conditions, not only the Hermite-Gaussian modes but also ring-trajectory modes are obtained. Under the unstable resonator condition, the diffraction loss of the resonator eigenmode significantly depends on the wavelength. At the wavelength of minimum diffraction loss, the highly directional beams propagate along the closed repetitive trajectories inside the resonator.

Cylindrical microwave resonator sensors for measuring materials under flow

Abstract: Dissertation for the degree of Doctor of Science in Technology to be presented with due permission for public examination and debate in Auditorium S4 at the Helsinki University of Technology (Espoo, Finland) on the 26 th of May, 2000, at 12 o'clock noon. I wish to express my gratitude to Hans-Olav Hide, Arnstein Wee, and my other colleagues at Multi-Fluid/Roxar, who gave me the opportunity to work with the development of microwave sensors for the oil industry and fuelled my interest by providing research and development challenges, and for many interesting discussions regarding the applications. Especially I am grateful to Årstein Bringsvor, Jörn Bolstad, Jone Mellemstrand, and Stein Rörtveit, who have participated in the projects in various ways, and to Frode Knudsen, who initially asked the question that ignited the research on sectorial and semisectorial waveguides and their applications. Finally, I wish to express my deep gratitude to my parents Marita and Börje, and my wife Brit and our children Malin and Emil for their support and patience. ABSTRACT In this thesis the various possibilities of implementing microwave sensors for measureing materials flowing in pipes are studied, with special emphasis on full-bore resonator sensors. With such resonator sensors a method to confine the electromagnetic energy in the sensor must be used. Two main principles are studied in detail, the principle of resonance below cutoff , and the design using end grids. The first principle is shown to allow sensors with fairly open, or even completely nonintrusive structures to be designed. The second often involves sectorial or semisectorial structures. The waveguide modes in sectorial and semisectorial waveguides are therefore analyzed. From the analysis of the sectorial waveguides came the idea for a new type of resonator sensor based on the principle of resonance below cutoff , the cylindrical fin resonator sensor (CFR). Various design aspects of this sensor are studied based on calculations, measurements, and simulations using the Hewlett-Packard HFSS software. A sensor suitable for measuring the composition of mixtures of hydrocarbons and water is developed based on the discussion. The sensor has a simple mechanical structure and is less expensive to manufacture than the end grid sensors. Various designs of end grids are compared based on theoretical considerations, simulations, and measurements, and recommendations for optimized designs are given. The ring grid with eight sectors and a ratio of radii of roughly 40% is shown to provide the best isolation for …

Tunable dielectric resonators with dielectric tuning disks

Abstract: Turnable dielectric resonators with dielectric tuning disks in cylindrical and rectangular enclosures are modeled by mode matching method. Tuning properties of TE/sub 01/ mode such as tuning ranges, spurious mode separation, unloaded quality factors, couplings, etc., are investigated for both rod- and ring-type dielectric resonators. Wide tuning ranges are obtained while other properties of resonators are maintained over the tuning ranges.

Single and multiband quarter wave resonator

Abstract: A single or multiple band quarter wave resonator antenna assembly for a communications device including a resonator element as a substrate element having disposed thereupon at least a pair of conductor trace elements. The conductor trace elements are disposed upon opposite sides of the substrate element and are operatively coupled to the communications device. The antenna assembly further including a separate conductive member having an approximate ¼ wavelength or greater dimension, which may be defined as the internal printed wiring board ground plane of the communications device.

Adjusted directivity dielectric resonator antenna

Abstract: A dielectric resonator antenna having a resonator formed from a dielectric material mounted on a ground plane with a conductive skirt. The ground plane is formed from a conductive material. First and second probes are electrically coupled to the resonator for providing first and second signals, respectively, to or receiving from the resonator. The first and second probes are spaced apart from each other. The first and second probes are formed of conductive strips that are electrically connected to the perimeter of the resonator and are substantially orthogonal with respect to the ground plane. A dual band antenna can be constructed by positioning and connecting two dielectric resonator antennas together. Each resonator in the dual band configuration resonates at a particular frequency, thereby providing dual band operation. The resonators can be positioned either side by side or vertically. Further advantage is obtained by mounting the dual antenna stack within a radome.