Showing papers on "Dielectric resonator antenna published in 2001"

Dielectric resonator antenna array with steerable elements

Abstract: An array of dielectric resonator antenna elements (1), each element (1) being composed of a dielectric resonator disposed on a grounded substrate (3), a plurality of feeds (2) for transferring energy into and from the dielectric resonator elements (1), wherein the feeds (2) of each element (1) are activatable either individually or in combination so as to produce at least one incrementally or continuously steerable beam which may be steered through a predetermined angle. Both the element beam patterns generated by the individual elements (1) and the array factor generated by the array as a whole may be independently steered. When these are steered in synchronism, it is possible to improve the overall gain of the array in any particular direction.

Dual-mode stepped-impedance ring resonator for bandpass filter applications

Abstract: It is well known that two orthogonal resonant modes exist within a one-wavelength ring resonator. In this paper, we focus on a ring resonator possessing an impedance step as a form of perturbation. A convenient analyzing method for obtaining the resonance characteristics of this resonator structure is presented. Furthermore, generation of attenuation poles obtained by the dual-mode ring resonator is discussed. In addition, a filter design method based on this resonator is explained, followed by experimental results, which prove the validity of the proposed design method.

Dielectric resonator antenna for a mobile communication

Abstract: A hemispherical dielectric resonator is arranged on a metal substrate to make a flat surface of the hemispherical dielectric resonator contact with the metal substrate, and a dielectric wave-guiding channel is connected with a curved side surface of the hemispherical dielectric resonator. Therefore, a dielectric resonance antenna in which the hemispherical dielectric resonator and the dielectric wave-guiding channel are placed on the same metal substrate is obtained. A signal transmitting through the dielectric wave-guiding channel is fed in the hemispherical dielectric resonator, the hemispherical dielectric resonator is resonated, and an electromagnetic wave is radiated. Therefore, the dielectric resonance antenna functions as a wave radiation device.

Coaxial dielectric rod antenna with multi-frequency collinear apertures

Abstract: An antenna. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source 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.

Method of providing differential frequency adjusts in a thin film bulk acoustic resonator (FBAR) filter and apparatus embodying the method

Abstract: A method for fabricating a resonator, and in particular, a thin film bulk acoustic resonator (FBAR), and a resonator embodying the method are disclosed. An FBAR is fabricated on a substrate by mass loading piezoelectric (PZ) layer between two electrodes. For a substrate having multiple resonators, only selected resonator is mass loaded to provide resonators having different resonance frequencies on the same substrate.

Improved bulk wave resonator coupling coefficient for wide bandwidth filters

Abstract: Resonator coupling coefficient plays a key role in determining the bandwidth of acoustically or electrically coupled resonator filters. This paper presents a method using high mechanical impedance electrodes to increase the effective coupling coefficient for bulk acoustic wave (BAW) resonators in the solidly mounted resonator (SMR) or membrane (FBAR) configurations.

Bandwidth enhancement for split cylindrical dielectric resonator antennas

Abstract: A numerical study of split cylindrical dielectric resonator antennas on a conducting ground plane excited by a coaxial probe is presented. The numerical solution is based on the method of moments for a body of revolution coupled to a wire. We consider in this study bandwidth enhancement for dielectric resonators excited in the HEM 11 and HEM 12 modes for the split dielectric cylinder. A wideband performance of about 35% has been achieved for the antenna and experimental measurements have verified this finding.

Radio communication device with integrated antenna, transmitter, and receiver

Abstract: First to third dielectric layers (201-203) are deposited to form a multilayered dielectric substrate (220). A plurality of conductor patches (204a-204d) are formed on the surface of the first dielectric layer (201). An antenna-feeding microstrip line (205) is formed between the first and second dielectric layers. A ground layer (206) is formed between the second and third dielectric layers (202, 203). Microstrip lines (208a, 208b) for high-frequency circuits are formed on the back of the third dielectric layer (203). The ground layer (206) has a slot (207) though which the antenna-feeding microstrip line (205) and the high-frequency microstrip line (208a) are coupled electromagnetically. Thus, the efficiency and directivity of an antenna are improved.

Micromechanical resonator device and micromechanical device utilizing same

Abstract: A micromechanical resonator device and a micromechanical device utilizing same are disclosed based upon a radially or laterally vibrating disk structure and capable of vibrating at frequencies well past the GHz range. The center of the disk is a nodal point, so when the disk resonator is supported at its center, anchor dissipation to the substrate is minimized, allowing this design to retain high-Q at high frequency. In addition, this design retains high stiffness at high frequencies and so maximizes dynamic range. Furthermore, the sidewall surface area of this disk resonator is often larger than that attainable in previous flexural-mode resonator designs, allowing this disk design to achieve a smaller series motional resistance than its counterparts when using capacitive (or electrostatic) transduction at a given frequency. Capacitive detection is not required in this design, and piezoelectric, magnetostrictive, etc. detection are also possible. The frequency and dynamic range attainable by this resonator makes it applicable to high-Q RF filtering and oscillator applications in a wide variety of communication systems. Its size also makes it particularly suited for portable, wireless applications, where, if used in large numbers, such a resonator can greatly lower the power consumption, increase robustness, and extend the range of application of high performance wireless transceivers.

Thin film bulk acoustic resonator (FBAR) and inductor on a monolithic substrate and method of fabricating the same

Abstract: An apparatus having both a resonator and an inductor fabricated on a single substrate and a method of fabricating the apparatus are disclosed. The apparatus includes a resonator and an inductor that is connected to the resonator. Both the resonator and the inductor are fabricated over their respective cavities to produce a high Q-factor filter circuit.

Near-field scanning microwave probe based on a dielectric resonator

Abstract: We report a near-field microwave microscopy based on a novel scanning probe—a long and narrow slot microfabricated on the convex surface of the dielectric resonator. The probe is mounted in the cylindrical waveguide. Tunable coupling to the probe is effectuated through the variable air gap. The whole probe is very compact, has a coaxial input, operates at 25–30 GHz, has a spatial resolution of 1–10 μm and, most important, has a low impedance of ∼20 Ω. This allows us to use it for characterization of metallic layers with high conductivity, in particular, thickness mapping.

Dielectric resonators raise your high-Q

Abstract: High-quality resonating elements are the key to the function of most microwave circuits and systems. They are fundamental to the operation of filters and oscillators, and the performance of these circuits is primarily limited by the resonator quality factor. At microwave frequencies, the quality factor (Q) of metal transmission line resonant circuits is proportional to volume. As a result, waveguide structures are often employed to increase Q at the expense of size, weight, and cost. Dielectric resonators overcome these limitations due to the fact that their losses are dominated by dielectric loss (loss tangent), and only in small part to metallic losses (housing). Dielectric losses are improving constantly, whereas metal losses, with the exception of superconductors, have remained substantially the same. These resonators can be made to perform the same functions as waveguide filters, but are, in contrast, very small, stable and lightweight. The popularization of low-loss dielectric resonators roughly coincides with the miniaturization of many of the other associated elements of most microwave circuits. When taken together, these technologies permit the realization of small, reliable, lightweight and stable microwave systems.

Micromechanical tunable capacitor and an integrated tunable resonator

Abstract: The invention relates to an arrangement for an integrated tunable resonator for radio and a method for producing the same. In particular the invention relates to an RF resonator realised with a micromechanical tunable capacitor with high Q- (quality factor) value and a method for fabricating the same. In one particular embodiment of the arrangement in accordance with the invention the first conducting layer (4) forms the first capacitor electrode (8), and/or the electrodes (9) to create the electrostatic force on the movable micromechanical structure (2), and the interconnecting wire (10) between the inductor coil (1) and the capacitor electrode. The invention presents a substantial improvement to the linearity, power consumption, occupation space and reliability of RF resonator circuits.

Surface-acoustic-wave pressure sensor and associated methods

Abstract: A pressure and temperature sensor includes a sealed insulating package and an elastic, piezoelectric substrate deformably supported within the package. At least three surface-acoustic-wave resonators are affixed to a bottom of the substrate. A first and a second resonator are positioned in parallel relation along the substrate. A third resonator has a long axis nonparallel to the long axes of the first and the second resonator. The temperature coefficients of the first and second resonators are substantially equivalent; that of the third is different from those of the first and the second resonator, for permitting a temperature change to be sensed. Electrical connectors extend between the resonators to the outside of the package. A sensing system also includes an antenna for sending and receiving electromagnetic signals to and from the device.

Frequency-tunable microwave dielectric resonator

Abstract: A new type of tunable composite dielectric resonator (DR) has been designed, In the structure of this DR, a controllable insert was used to change the resonance frequency (f/sub 0/) in a wide spectral range, while preserving a high quality factor. The simplest of proposed resonance systems for obtaining f/sub 0/ control is a microwave DR crossed by an air slot, which is controlled by fast piezoelectric actuator. Analytical and experimental techniques were employed for optimization of the composite DR structure. It has been observed that this device can create a change up to 20%-25% in its resonance frequency.

Thin film resonator and method for manufacturing the same

Abstract: A thin film resonator having enhanced performance and a manufacturing method thereof are disclosed. The thin film resonator includes a supporting means, a first electrode, a dielectric layer and a second electrode. The supporting means has several posts and a supporting layer formed on the posts. The first electrode, the dielectric layer and the second electrode are successively formed on the supporting layer. The thin film resonator is exceptionally small and can be highly integrated, and the thickness of the dielectric layer of the resonator can be adjusted to achieve the integration of multiple bands including radio, intermediate and low frequencies. Also, the thin film resonator can minimize interference and has ideal dimensions because of its compact substrate, making the thin film resonator exceptionally small, yet comprising a three-dimensional, floating construction.

Wavelength selective optical add/drop multiplexer and method of manufacture

Abstract: One embodiment of the present invention is an exemplary wavelength selective optical coupling device. This exemplary device includes two waveguides, a ring or disc resonator, and resonator coupling elements. The waveguides are disposed on top of a substrate, not in contact with each other. The waveguides may transmit multiple wavelengths of light. The ring or disc resonator includes a dielectric member which extends parallel to the top of the substrate and overlaps, without contacting, the waveguides. The resonator is sized to resonate at a subset of resonant wavelengths. The resonator coupling elements couple the resonator to the substrate. The resonator coupling elements may include a bridge coupled to the top surface of the substrate and electrically coupled to control circuitry within the substrate. A waveguide coupling signal from the control circuitry causes the bridge to deform, translating the resonator up and down, thereby intermittently coupling and decoupling the waveguides.

Use of parasitic strip to produce circular polarisation and increased bandwidth for cylindrical dielectric resonator antenna

Abstract: An experimental investigation is undertaken to determine the effect on the bandwidth and polarisation of a cylindrical dielectric resonator antenna when a parasitic strip is attached to its surface. Particular configurations are found that increase the bandwidth and produce circular polarisation.

1-D photonic bandgap resonator antenna

Abstract: This paper presents a theoretical method used to realize a 1-D photonic bandgap (PBG) resonator antenna. Studies in the frequency and space domain were made to determine the properties of the material. Then a 1-D PBG resonator antenna was designed, and some characteristics of the antenna were shown as the radiation pattern, the linear, and the circular polarization. The results show that such a device permits us to obtain high gain with a very thin structure. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 312–315, 2001.

Resonator and high-frequency filter

Abstract: The resonator of the present invention includes a cylindrical dielectric and a conductor film covering the surface of the dielectric in close contact therewith. The conductor film is constructed of a cylindrical portion and two flat portions, and is formed by subjecting the surface of the dielectric to metallization or the like. With the conductor film formed in close contact with the dielectric, deterioration of the Q value and the like caused by instability of connection at the corners can be suppressed even when a radio frequency induced current flows from the cylindrical portion over the two flat portions.

Bulk acoustic wave resonator with a conductive mirror

Abstract: A method of fabricating a bulk acoustic wave (BAW) resonator and a BAW resonator so fabricated, the method including the steps of: providing a substrate; providing a first isolation structure; and providing a resonator section including a piezolayer; wherein the first isolation structure includes an acoustic mirror made from only electrically conductive layers of alternating high and low acoustic impedance. In some applications, the first isolation structure is situated between the resonator section and the substrate, while in other applications, the first isolation structure is situated above the resonator section (on the side of the resonator section facing away from the substrate), so that the resonator section lies between the first isolation structure and the substrate, and the resonator then further comprises a second isolation structure situated between the resonator section and the substrate. In some applications where the first isolation structure is situated above the resonator section, the second isolation structure includes an acoustic mirror made from layers of materials of alternating high and low acoustic impedance, and in other such applications, the second isolation structure includes a membrane. In yet still other applications where the first isolation structure is situated above the resonator section, the method of the invention also includes the step of providing a flip-chip ball on top of the first isolation structure. The method also includes, for some applications, the step of providing a capping material positioned so that the first isolation structure and resonator section are sandwiched between the substrate and the capping material.

Dielectric leak wave antenna having mono-layer structure

Abstract: The present invention provides a dielectric leaky-wave antenna having a single-layer structure which is effective for realizing a highly efficient low-cost antenna in a quasi-millimeter wave zone in particular. This dielectric leaky-wave antenna includes a ground plane, a dielectric slab which is laid on one surface of the ground plane and forms a transmission guide for transmitting an electromagnetic wave from one end side to the other end side between itself and the ground plane along the surface, perturbations which are loaded on the surface of the dielectric slab along the electromagnetic wave transmission direction of the transmission guide at predetermined intervals and leak the electromagnetic wave from the surface of the dielectric slab, and a feed which supplies the electromagnetic wave to one end side of the transmission guide.

Multilayer electronic part, multilayer antenna duplexer, and communication apparatus

Abstract: A multilayer filter comprising a first dielectric layer (2101a) having a first shield electrode provided on one major surface, a second dielectric layer (b) having a resonator electrode provided on the one major surface, a third dielectric layer (2101c) having a bond electrode provided oppositely to a part of the resonator electrode on the one major surface, a fourth dielectric layer (2101d) having a second shield electrode provided on the one major surface, a fifth dielectric layer (2101e) where at least the one major surface is exposed to the outside, and a ground electrode (2108) provided on the other major surface of the first dielectric layer and/or the one major surface of the fifth dielectric layer, characterized in that the first ground electrode and the first shield electrode are connected electrically through a via hole (2109) made in the first dielectric layer.

Dual‐polarized dielectric resonator antennas

Abstract: Two feeding designs for achieving dual orthogonal linear polarization operations of dielectric resonator (DR) antennas fed by microstrip lines are demonstrated. The microstrip feedlines can be placed directly under the DR or conformal to the surface of the DR. Good dual-polarization excitation can be obtained for the two feeding designs. Experimental results for the return loss, isolation between two feeding ports, and radiation patterns are presented and discussed. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 222–223, 2001.

Tunable all-pass optical filters with large free spectral ranges

Abstract: In accordance with the invention, a tunable optical all-pass filter comprises a substrate-supported multilayer waveguiding structure comprising a first layer including a waveguiding optical ring resonator, a second layer for spacing, and a third layer including a curved waveguide. The curved waveguide is optically coupled to the resonator by two spaced apart optical couplers extending through the spacing layer, and tunability is provided by a first phase-shifter to control the optical pathlength of the resonator and a second phase-shifter operative on the waveguide to control the strength of coupling between the waveguide and the resonator. In one embodiment, the waveguide and the resonator are horizontally spaced apart in the non-coupling regions to provide optical isolation. In another, the waveguide and resonator can overlap horizontally, but the spacer layer is thicker in the non-coupling regions to provide optical isolation.

Complex resonance and radiation of hemispherical dielectric-resonator antenna with a concentric conductor

Abstract: The probe-fed hemispherical dielectric-resonator antenna (DRA) with a concentric conductor is studied theoretically in this paper. Using the mode-matching method, the exact Green's functions for evaluation of the input impedance and radiation patterns are found, with the functions presented in computationally efficient forms. The moment method is used to determine the probe current and, hence, the input impedance as well as the radiation patterns. The results are verified by special cases available in the literature. In this paper, the effects of the conductor radius, dielectric constant, probe length, and probe displacement on the input impedance are investigated. The theory is very general and, by taking appropriate limits, can be used to study the solid DRA and the conductor-loaded wire antenna. To aid the DRA design engineer, the TE/sub 111/-mode characteristic equation of the DRA is also studied, from which the simple formulas for the resonant frequency and Q-factor are obtained.

Multi-beam switched parasitic antenna embedded in dielectric for wireless communications systems

Abstract: A nine monopole antenna embedded in a dielectric cylinder mounted on a small ground plane has been designed for IEEE 802.11 applications. Two simultaneous beams are controlled electronically with a front-to-back ratio of 12 dB and 13% bandwidth. The dielectric reduced the footprint by 85% and the antenna volume by 91% compared to an array with similar functionality in air.

Energy losses in an acoustical resonator

Abstract: A one-dimensional model has recently been developed for the analysis of nonlinear standing waves in an acoustical resonator. This model is modified to include energy losses in the boundary layer along the resonator wall. An investigation of the influence of the boundary layer on the acoustical field in the resonator and on the energy dissipation in the resonator is conducted. The effect of the boundary layer is taken into account by introducing an additional term into the continuity equation to describe the flow from the boundary layer to the volume. A linear approximation is used in the development of the boundary layer model. In addition to the viscous attenuation in the boundary layer, the effect of acoustically generated turbulence is modeled by an eddy viscosity formulation. Calculatons of energy losses and a quality factor of a resonator are included into the numerical code. Results are presented for resonators of three different geometries: a cylinder, a horn cone, and a bulb-type resonator. A comparison of measured and predicted dissipation shows good agreement.

Multi-segmented dielectric resonator antenna

Abstract: A radiating antenna capable of generating or receiving radiation using a plurality of dielectric resonator segments disposed in a circular array is disclosed. The purpose of using multiple dielectric resonator segments within a single antenna system is to produce several beams each having a "boresight" (that is, a direction of maximum radiation on transmit, or a direction of maximum sensitivity on receive) 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. When two segments are excited simultaneously, the antenna may have a narrower main lobe and/or a smaller backlobe than for a single segment alone. When receiving radio signals, electronic processing of such multiple beams may be used to find the direction of those signals, thus forming the basis of a radio direction finding device. Further, by forming a transmitting beam or resolving a receiving beam in the direction of the incoming radio signal, a "smart" or "intelligent" antenna may be constructed. Beamsteering and smart antenna technology may also be used to steer a sharp null in a particular direction to avoid transmitting there or to avoid receiving interfering signals from that direction. The dielectric resonator segments are mounted on a ground plane, are substantially cylindrical or trapezoidal segments in shape, and are fed by internal probes or external ground plane apertures.

Circularly polarised dielectric resonator antenna excited by perturbed annular slot with backing cavity

Abstract: The circularly polarised dielectric resonator antenna excited by a perturbed annular slot is investigated experimentally. A backing cavity is placed beneath the slot to block undesirable backside radiation. The effects of varying the slot on the return loss and axial ratio are discussed. The radiation patterns and antenna gain of the configuration are also presented.