Showing papers on "Dielectric resonator antenna published in 1997"

Broadband nonhomogeneous multi-segmented dielectric resonator antenna system

Abstract: A dielectric resonator antenna system is disclosed wherein a dielectric material having a high dielectric constant is placed between a dielectric resonator antenna (DRA) and the antenna feed. Preferably the dielectric material having a high dielectric constant is either in the form of an insert within a cavity of the DRA or alternatively is in the form of a thin layer between the feed and the DRA for enhancing coupling therebetween. It is preferred that the high dielectric constant material be at least twice the value of the dielectric resonator antenna.

Electrically active resonant structures for wireless monitoring and control

Abstract: A planar electromagnetic resonator utilizes an electromagnetically active material located between the capacitive or inductive elements of the resonator. A microscopic electrical property of this material is altered by an external condition, and that alteration, in turn, affects the behavior of the resonator in a consistent and predictable manner.

Antenna and method for receiving or transmitting radiation through a dielectric material

Abstract: A low profile, receiving and/or transmitting antenna is adapted to be mounted onto an interior portion of a building or other structure to receive or transmit radiation through a first dielectric material, such as a window, associated with the building or other structure. The antenna includes a receiving/transmitting horn filled with a second dielectric material and a surface for mounting the antenna to the first dielectric material so that the horn is disposed at a particular angle with respect to a surface of the first dielectric material. A matching layer may be disposed between the first dielectric material and the second dielectric material to provide for a reflectionless match between the first and second dielectric materials.

A micromachined high-Q X-band resonator

Abstract: The authors present a new structure which can be used as a microwave high-Q resonator for the development of narrow-band low-loss filters in a planar environment. The resonator is made of a low-loss micromachined cavity which is easy to integrate with monolithic circuits. Compared to conventional metallic resonators, the performance of this resonator is similar, but the weight and size are significantly reduced.

Method for fabricating piezoelectric resonators and product

Abstract: A method for fabricating piezoelectric resonators on a substrate such that the resonant frequency of one resonator is shifted by a small amount from another of the resonators. By means of differential fabrication of the electrodes, the thickness of the metal in an electrode for one resonator is increased relative to that of another resonator to obtain the shift in resonant frequency. The frequency of a single resonator also may be adjusted to a specific frequency by the addition of a differential layer of metal to one of the electrodes comprising the resonator. Mask alignment errors in the differential fabrication process cause non-uniformities in the thickness of the metal in the electrode which non-uniformities significantly degrade the performance of the resonator. The areas of non-uniform thickness of electrode that degrade the performance are removed in this process.

Resonator modulators and wavelength routing switches

Abstract: The invention provides an optical switch and modulator which uses a closed loop optical resonator. The optical resonator is a dielectric cavity whose primary function is to store optical power. Various structures are possible, and a particularly advantageous one is a ring shaped cavity. The wavelength response at the output port of a ring resonator side coupled to two waveguides is determined by the details of the resonator, and the coupling between the resonator and the waveguides. By coupling to adjacent resonators, the modulator response can be improved over that of a single resonator. One such improvement is in modulator efficiency, which is defined as the ratio of the change in optical intensity at the output, to a change in absorption in the ring waveguides. Absorption is used for switching and modulation without incurring significant optical attenuation. Another improvement involves making the resonance insensitive to small deviations in wavelength or index change. The latter improves fabrication tolerances and compensates for possible drift of the signal wavelength. Collectively, the behavior of multiple coupled resonators yields higher order responses.

Half volume dielectric resonator antenna designs

Abstract: The authors demonstrate that the volume of a conventional dielectric resonator antenna (DRA) can be reduced by approximately half. The technique relies on employing an additional conducting plate in the DRA, which acts as an electric wall. Experimental and simulation results are provided for cylindrical and rectangular dielectric resonator antenna designs.

Whispering gallery modes in a dielectric resonator: characterization at millimeter wavelength

Abstract: Applications of whispering-gallery-mode (WGM) dielectric resonators in the millimeter and submillimeter frequency range are discussed. A summary of the main peculiarities of these resonators is given, and a method to obtain approximate analytical expressions of electromagnetic field components is developed. Problems connected with the excitation by far infrared (FIR) laser radiation are examined. The analysis of electromagnetic propagation in different structures drives the best choice for the transmission line (metallic and dielectric waveguides), and the same theoretical analysis allows to face the basic problem of optimizing the matching between transmission-line and WG resonators; the role in this application of dielectric waveguides with variable diameter is discussed. All of the predictions are obtained in a unified theoretical picture. The experimental characterization of a WG resonator at 240 GHz involved the measurement of the effectiveness of the coupling between the transmission line and the resonator, the determination of the merit factor and free spectral range for the different resonance families in different resonators. Accurate measurements were carried out to acquire knowledge of the field distribution in both axial and radial directions; to this purpose, dielectric antennas with high directivity were used to sense the field intensities for different resonance modes. The good agreement between the experimental results and the theoretical predictions is carefully discussed.

Slot-coupled DR antenna for dual-frequency operation

Abstract: To achieve dual-band operation or wider bandwidth, a new configuration of dielectric resonator antenna is proposed. This structure consists of two rectangular dielectric resonators displaced near two edges of a single slot in the ground plane of a microstrip line. The measured impedance and radiation patterns for two cases are presented. The results for typical examples indicate that an impedance bandwidth twice that of a single element or dual-frequency operation at two separate bands can be achieved.

Bandwidth enhancement of dielectric resonator antenna by loading a low-profile dielectric disk of very high permittivity

Abstract: The aperture-coupled cylindrical dielectric resonator (DR) antenna loaded by a low-profile DR disk of very high permittivity is studied experimentally. By using the low-profile parasitic DR disk the antenna bandwidth can be increased from 8% bandwidth to 25%. The characteristics of the new configuration are measured and discussed.

Bandwidth and gain enhancement of a dielectric resonator antenna with the use of a stacking element

Abstract: The stacked structure of an aperture-coupled cylindrical dielectric resonator (DR) antenna is studied experimentally The effects of the offset and the air gap between the driven and parasitic DR elements are investigated It is found that the bandwidth of the stacked structure can increase from the single-element value of 9% to 37% The voltage standing-wave ratio, the radiation patterns, and the antenna gain are also reported © 1997 John Wiley & Sons, Inc Microwave Opt Technol Lett 14: 215–217, 1997

Gain-enhanced miniaturised rectangular dielectric resonator antenna

Abstract: A double-layered high permittivity dielectric resonator (DR) was investigated experimentally at the 1.8 GHz band. The measured results show that the double-layered DR antenna has a 1.2 dB gain enhancement and 25% height reduction over a single-layered antenna. The bandwidth is 2.7% and antenna gain is 6.2 dBi.

Double resonant wideband patch antenna and method of forming same

Abstract: A double resonant wideband patch antenna (100) includes a planar resonator (101) forms a substantially trapezoidal shape having a non-parallel edge (103) for providing a substantially wide bandwidth. A feed line (107) extends parallel to the non-parallel edge (103) for coupling while a ground plane (111) extends beneath the planar resonator for increasing radiation efficiency.

Synthesis and Design of Cascaded Trisection (CT) Dielectric Resonator Filters

Abstract: Synthesis of filters having asymmetric insertion loss poles as cross-coupled cascaded trisections (CT) of resonators is presented. The theory is applied to the design and realization of cellular PCS base station dielectric resonator filters with extremely demanding requirements on selectivity, out of band rejection and pass band insertion loss. Measured results are presented which demonstrates the validity and accuracy of the theory and design.

Embedded dielectric resonator antenna for bandwidth enhancement

Abstract: A new embedded structure with an annular ring and a cylindrical dielectric resonator excited by means of a coaxial probe has been realised and investigated experimentally to obtain a large bandwidth enhancement. The return loss, radiation patterns, and antenna gain of this configuration are presented. The capability of such an antenna, with a low profile (a/h = 6) and 10 dB impedance bandwidths of 32 and 38%, is demonstrated.

RF-tags utilizing thin film bulk wave acoustic resonators

Abstract: An RF tag having an antenna for receiving a RF signal having a frequency band between first and second frequencies and an acoustical resonator having a resonant frequency related to the first and second frequencies. The acoustical resonator has first and second electrodes that sandwich a layer of piezoelectric material. The antenna is connected to one of these electrodes. The resonator filters the signal received on the antenna. The filter can function either as a notch filter or as a bandpass filter. A resonator that acts as a bandpass filter includes a third electrode and a second layer piezoelectric material sandwiched between the second electrode and the third electrode. A frequency multiplier circuit may be incorporated in the RF tag to provide a response signal that occupies a frequency band at a frequency above the second frequency. In one embodiment of the present invention, multiple resonators having different resonant frequencies are utilized to generate a response code. In one embodiment of the present invention, the resonators are suspended on a support member over a substrate at locations on the support member which differ in thickness.

Voltage-controlled oscillator having a semiconductor integrated circuit, a piezoelectrics resonator and a diode and variable-capacitance diode

Abstract: A voltage-controlled oscillator is provided having a semiconductor integrated circuit and a piezoelectric resonator. A variable-capacitance diode may be connected in series with the piezoelectric resonator. The variable-capacitance diode may be further mounted a land of a lead frame. The piezoelectric resonator, variable-capacitance diode and lead frame may be resin molded into a single unit. In operation, a signal may be applied to a node located between the variable-capacitance diode and the DC-cutting capacitor.

Ceramic multilayer helical antenna for portable radio or microwave communication apparatus

Abstract: A small and durable antenna for use with radio and microwave communications is formed as a helical conductor contained in a multilayered non-ferrite ceramic chip. The dielectric constant of the ceramic is selected to match the antenna to its operating frequency, which may be in the range of 0.5 to 10.0 Gigahertz. A process for making such antennas is also disclosed. The antenna may be used in portable terminals and other devices requiring small, durable and inexpensive antennae.

Dielectric TM mode resonator for RF filters

Abstract: A TM mode dielectric resonator and a filter comprising such a resonator The resonator includes metallic walls defining a cavity A dielectric resonator body is accommodated within the cavity An end surface of the dielectric resonator body is located in the vicinity of one cavity wall, so as to provide a spacing between said end surface and said cavity wall, at least in a region corresponding to a portion of said end surface The spacing can be obtained by washers, arranged between the dielectric resonator body and said cavity wall It can also be obtained by means of a recess in said cavity wall, one or more protrusions on said cavity wall, or a metallic or dielectric ring arranged between the dielectric resonator body and said cavity wall

Detecting at least one characteristic of material by evaluating HF resonator tuning

Abstract: The detection method includes the supply of microwaves to a HF resonator arrangement (1) which has a resonator (21). Microwaves with at least two different frequencies are supplied. The resonant frequency shifts are determined, by the comparison of the resonance curves of the resonator, uninfluenced and influenced by the material. The damping is determined by comparing the amplitudes of the resonance curves with the frequencies of the supplied microwaves. Microwaves of at least two frequencies are continuously supplied to the resonator. The frequencies of the microwaves are alterd periodically.

RMS energy conversion

Abstract: An energy conversion device comprises an acoustic resonator, a pulse combustion device for creating a standing wave within said resonator, and an electric alternator. The alternator is coupled to the resonator to convert acoustically driven mechanical vibrations into electrical power.

Polarimetric dual band radiating element for synthetic aperture radar

Abstract: A dual band, dual polarized antenna comprising an array of resonators in a plane for radiating at a first frequency, a ring resonator in a plane, the array of resonators being contained within a projection of the boundary of the ring resonator, the ring resonator for radiating at a second frequency which is lower than the first frequency, apparatus for exciting the array of resonators to cause them to radiate at the first frequency with dual polarizations simultaneously, and apparatus for exciting the ring resonator to cause it to radiate at the second frequency with dual polarizations simultaneously.

Microstrip-fed array of multisegment dielectric resonator antennas

Abstract: A novel antenna is presented consisting of an array of multisegment dielectric resonator antennas fed by a multilayer microstrip branch-line network. A prototype array has been designed and fabricated at X-band and its measured performance includes a gain peak of 15.4 dBi with a 3 dB gain bandwidth of 17% and an efficiency of 66%. This array can be used as a medium gain, wideband antenna, or can form a subarray in a large low-profile structure for high gain applications.

Dielectric resonator filter configured to filter radio frequency signals in a transmit system

Abstract: A dielectric resonator filter is configured to suppress emissions in an out-of-band frequency portion of an amplified radio frequency (RF) signal prior to transmission of the RF signal by an antenna assembly. The filter includes plural tunable resonant cavities, each of which have a dielectric resonator and are arranged to suppress a magnitude of a frequency component in the out-of-band frequency portion of the RF signal. The amplified RF signal is applied to the plural resonant cavities with a microstrip transmission line. The dielectric resonators are arranged so as to automatically compensate for temperature-induced resonance condition variations.

Method and device for measuring at least one property of a substance

Abstract: The detection method includes the supply of microwaves to a HF resonator arrangement (1) which has a resonator (21). Microwaves with at least two different frequencies are supplied. The resonant frequency shifts are determined, by the comparison of the resonance curves of the resonator, uninfluenced and influenced by the material. The damping is determined by comparing the amplitudes of the resonance curves with the frequencies of the supplied microwaves. Microwaves of at least two frequencies are continuously supplied to the resonator. The frequencies of the microwaves are altered periodically.

Excitation of dielectric resonator antenna using a soldered-through probe

Abstract: A soldered-through probe is used to excite the dielectric resonator antenna (DRA) A cylindrical ring DRA is used to demonstrate the feasibility of this excitation method The return loss, radiation pattern, and antenna gain of the new configuration are studied

Dielectric resonator and filter utilizing a non-radiative dielectric waveguide device

Abstract: A dielectric resonator capable of resonating at a predetermined resonance frequency has a dielectric substrate, a first electrode formed on a first surface of the dielectric substrate and having a first opening, a second electrode formed on a second surface of the dielectric substrate and having a second opening, a first conductor plate disposed by being spaced apart from the dielectric substrate by a predetermined distance, and a second conductor plate disposed by being spaced apart from the dielectric substrate by a predetermined distance, wherein at least one of said first and second conductor plates is electrically connected to at least one of said first and second electrodes. The region of the dielectric substrate defined between the first and second electrodes, a free space defined between the first electrode and the first conductor plate and another free space defined between the second electrode and the second conductor plate are cut-off regions for attenuating a high-frequency signal having the same frequency as the resonance frequency. This dielectric resonator can be used in a millimeter wave band, can resonate with markedly small variations of its resonance frequency even if the temperature thereof varies, and can be manufactured at a low cost.

Measurements of unloaded Q-factor of transmission mode dielectric resonators

Abstract: A procedure to determine accurately the unloaded Q-factor, resonant frequency and coupling coefficients of a dielectric resonator in the transmission mode has been developed. The technique is based on a derived equation relating S/sub 21/ and Q/sub L/, measurements of S/sub 21/, S/sub 11/ and S/sub 22/ and accounts for crosstalk, coupling and cable losses.