Showing papers on "Dielectric resonator antenna published in 1996"

Measurements of the complex permittivity of microwave circuit board substrates using split dielectric resonator and reentrant cavity techniques

Abstract: The split dielectric resonator technique makes it possible to measure the real part of permittivity of isotropic materials for a very broad permittivity range and dielectric loss tangents in the range from 10⁻⁴ to 10⁻¹ with high accuracy. For uniaxially anisotropic materials, the split resonator method permits measurement of the permittivity and and the dielectric loss tangent in the plane parallel to the the sample bottoms. Additional measurements using re-entrant cavity enable determination of permittivity and the dielectric loss tangent perpendicular to this plane.

Input impedance of aperture-coupled dielectric resonator antennas

Abstract: Dielectric resonator antennas (DRA?s) excited by a narrow-slot aperture in a conducting ground plane are analyzed using a numerical technique based upon a surface-integral equation formulation for bodies of revolution (BOR's) coupled to non-BOR geometries. An efficient matrix-solution algorithm, together with a simple microstrip transmission-line model or a delta-source model are used to comnute the antenna inmt impedance. Input impedances obtained with this technique show favorable agreement to those obtained via another numerical technique, as well as to those obtained by measurement.

An investigation of a novel broadband dielectric resonator antenna

Abstract: Recently, dielectric resonator antennas (DRA) have been proposed as an alternative to the popular microstrip patch. Since then, research has continued, extending their performance capabilities and confirming their potential as low profile and efficient antenna elements for array applications. Also a single-point fed dielectric resonator antenna has been reported, capable of radiating a circularly polarized signal with a much wider axial ratio bandwidth than a similar single-point fed microstrip patch. Further capability enhancements of a dielectric resonator antenna have recently been demonstrated by fabricating the antenna from ferrite material. With a properly biased static magnetic field, it has been shown to possess frequency tuning and polarization diversity properties. The purpose of this paper is to present a novel development of a DRA which possesses a much wider operational bandwidth than previously reported. This improvement can be accomplished with a simple slot feed and without an elaborate matching circuit or a complicated stacking procedure which is generally required by the microstrip patch.

Lubricating fluid condition monitor

Abstract: A lubricating/hydraulic fluid condition monitor in which a coaxial microwave resonator is placed in a fluid conduit to determine changes in the chemical properties and debris concentration is disclosed. Microwave radiation is applied to the resonator for measuring the resonant frequency and resonator Q. An externally powered electric or magnetic field is used to alternately align and misalign debris in the fluid while the resonator properties are being measured. A logic unit automatically generates tables of resonant frequency and Q versus resonator mode and external field strength. This set of tables constitutes a fingerprint of the fluid condition. By matching the fingerprint against a set of fingerprints taken under known conditions, the condition of the fluid is determined. Changes in the fluid's dielectric constant caused by oxidation or the presence of water, changes in the concentration and size of conducting particles from bearing wear, and changes in viscosity all affect the fingerprint; and thus, can be monitored in real time. In a variation of the invention, a lumped-circuit resonator printed on a microwave circuit board is used as the sensor. In a further variation, a transmission-line resonator printed on a microwave circuit board is used as a sensor. In yet another variation the resonator is a lumped circuit waveguide structure through which the fluid flows. In still another variation, time domain reflectometry is used in a transmission line having one end immersed in the fluid.

Parasitic coplanar three-element dielectric resonator antenna subarray

Abstract: A slot-coupled rectangular dielectric resonator antenna in the parasitic coplanar configuration is investigated experimentally. The measured results for impedance and radiation patterns are presented for the three-element case. It is found that by using suitable choice of the dimensions and offset distance of each dielectric resonator, the impedance bandwidth can be as high as three times that of the single-element structure.

Circularly polarised higher-order rectangular dielectric-resonator antenna

Abstract: A circularly polarised, rectangular, low-profile, dielectric-resonator antenna is presented which is fed by a 50/spl Omega/ microstrip line through a single aperture. The measured 3dB axial-ratio bandwidth in the boresight direction is 14.35-14.80 GHz (3%). At 14.75 GHz, the input |s/sub 11/| is -28 dB; the measured pattern in one elevation plane decreases with increasing /spl theta/ but the axial ratio is close to 3 dB over 110/sup c/; in the orthogonal elevation plane, the axial ratio increases more rapidly with /spl theta/.

Circular polarised cylindrical dielectric resonator antenna

Abstract: A circular polarised cylindrical dielectric resonator antenna excited using a simple microstrip feed line is reported. The experimental results of the resonant frequency, radiation pattern, boresight axial ratio, gain, unloaded Q-factor, impedance bandwidth and radiation efficiency are presented.

Theoretical investigation of aperture-coupled rectangular dielectric resonator antenna

Abstract: Characteristics of an aperture-coupled rectangular dielectric resonator are investigated theoretically. A model based on the modal expansion method and the spectral domain approach is developed. Numerical results for Q factors, radiation efficiency and radiation patterns are presented for various values of material and structural parameters of the resonator, and it is found that by suitable choice of these parameters high efficiency, wide bandwidth and broadside radiation patterns can be achieved for the TE/sub 111//sup y/ mode. Effects of aperture dimensions, aperture displacement and open-stub length on input impedances are also discussed. Results for return losses and radiation patterns are compared with available measured data, showing reasonable agreement. The results presented should be useful for the design of this type of new antenna.

Array of circular-polarised cross dielectric resonator antennas

Abstract: A compact array of circular polarised cross-shaped dielectric resonator antennas (XDRAs) is presented. The array consists of 2/spl times/2 XDRAs elicited by microstrip-fed slot apertures in the X-band. By using sequential rotation to feed the XDRAs, the circular polarisation bandwidth is significantly increased from 5% for the individual XDRA to 16% in the array. The array also achieves a wide impedance bandwidth: a 10 dB return loss was maintained over a 25% bandwidth.

Offset dual-disk dielectric resonator antenna of very high permittivity

Abstract: An aperture-coupled offset dual-disk dielectric resonator antenna of very high permittivity is investigated experimentally. It is found that the new configuration offers an impedance bandwidth 4.6 times wider than that of the single element. The voltage standing wave ratio, radiation patterns, and antenna gain of the configuration are studied.

Varactor tuned helical resonator for use with duplex filter

Abstract: A radio frequency filter comprising several resonator circuits, such as duplex filter, is provides with a given passband. Signal frequencies generating spurious response, mirror frequencies, etc. can be effectively attenuated so that the filter comprises one more resonator circuit connected as a bandstop circuit. That comprises a transmission line resonator (Res), a series connection of an inductive element (MLIN2) and a capacitance diode (D), one end of the series connection being couples to a coupling point in the transmission line resonator, dividing it into two parts (TLIN1, TLIN2), and the other end being couples to the output connector (1) of the radio frequency filter. In addition, means are provided for carrying the direct voltage (V+) to the cathode of the capacitance diode, whereby the series resonance frequency changes according to the control voltage.

Ultrasonic bonding machine and resonator thereof

Abstract: To provide an ultrasonic bonding machine in which a resonator is arranged horizontally or vertically while it is supported at both ends and a resonator for use in the same. The interface Wa is placed on the mount 13 arranged in a stationary state in a lower portion of the working space 2 open in forward, right and left directions, the resonator 7 is moved down by the pressure mechanism 3 from above, and the interface Wa is pressure-held properly between the bonding working portion 11 and the mount 13 while it is in a stationary state and bonded with vibration energy of a vertical ultrasonic wave. The resonator 7 is assembled by interconnecting the ultrasonic horn having the bonding working portion 11 and two boosters having support portions by means of screws in such a manner that they are coaxial with one another, thereby facilitating exchange of each element. In addition, the resonator can be arranged vertically while it is supported at both ends in the front of the main body.

Inductor ring for providing tuning and coupling in a microwave dielectric resonator filter

Abstract: An inductive tuning disk for tuning a resonant frequency of a resonator of a microwave filter. The microwave filter includes a housing that encloses a cavity and a resonator therein. The resonator exhibits a magnetic field that appears in the cavity. The inductive tuning disk includes a dielectric base which is supported from a top wall of the housing by a support, and which is disposed within the cavity at an adjustable height above the resonator. The inductive tuning disk further includes an inductor ring which is disposed over a portion of a top surface of the dielectric base, and which is spaced apart from a center of the base. The inductor ring includes an electrically conductive material. The inductor ring interacts with the magnetic field to cause a resonant frequency of the resonator to vary as a function of the adjustable height. The disk may also be used to couple the magnetic energy between a pair of resonators of a filter.

Post-fabrication tuning of acoustic resonators

Abstract: A system is described that tunes the resonance frequency of a thin film acoustic resonator to a desired frequency after the resonator is fabricated. The resonator has a metal layer in an acoustic path of the resonator. The system includes a substantial vacuum reaction chamber within which the resonator is located. A heater is provided that heats the metal layer to an elevated temperature to either grow or etch the metal layer depending on a reaction gas introduced into the reaction chamber. A control circuit is also provided that controls the heater to heat the metal layer such that the thickness of the metal layer is adjusted to obtain the desired frequency after fabrication of the resonator. Methods of tuning the resonance frequency of the acoustic resonator to the desired frequency are also described.

L-resonator bandstop filters

Abstract: A design procedure is presented for TEM narrow bandstop filters using L resonators, which are intermediate of the gap- and parallel-coupled resonators typically used, having parallel coupling only over a portion of the resonator length and a grounded end in either the coupled or stub portion of the resonator.

Adjustable frequency dielectric resonator antenna

Abstract: An easy method of tuning the resonant frequency of cylindrical and ring dielectric resonator (DR) antennas using different diameters of conducting plates is presented. This technique can tune a DR antenna to operate at the design frequency without changing antenna performance. The maximum frequency tuning range can reach up to 300-500 MHz.

High-Q multi-layer ceramic RF transmission line resonator

Abstract: A high Q multi-layer ceramic transmission line resonator (100) used for RF applications. The resonator (100) includes a plurality of strips (102) which are separated by a ceramic substrate (104). Each of the strips are interconnected using vias (110) passing through the ceramic substrate (104). The invention utilizes current manufacturing processes to fabricate an equivalent thick center conductor to effectively increase the Q factor. This allows for the resonator to be used in miniature RF communication devices utilized in high tier devices such as voltage controlled oscillators (VCOs) or integrated filter circuits.

Dielectric resonator and dielectric resonator device using same

Abstract: A dielectric resonator capable of resonating at a predetermined resonance frequency has a dielectric substrate (3), a first electrode (1) formed on a first surface of the dielectric substrate (3) and having a first opening (4), a second electrode (2) formed on a second surface of the dielectric substrate (3) and having a second opening (5), a first conductor plate (211) disposed by being spaced apart from the dielectric substrate (3) by a predetermined distance, and a second conductor plate (212) disposed by being spaced apart from the dielectric substrate (3) by a predetermined distance. The region of the dielectric substrate (3) defined between the first and second electrodes (1, 2), a free space defined between the first electrode (1) and the first conductor plate (211) and another free space defined between the second electrode (2) and the second conductor plate (212) 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 variation of the resonance frequency even if the temperature thereof varies, and can be manufactured at a low cost.

Dielectric resonator for a microwave filter, and a filter including such a resonator

Abstract: A multimode composite resonator, in particular for a microwave filter, includes a resonant cavity, a dielectric resonator element disposed inside the cavity, a tuning element for each mode and a coupling element for coupling between modes. The resonator element is shaped to have plural vertices which are short-circuited together by the conductive walls of the cavity via direct or RF electrical contact between the vertices and the walls. Various geometrical resonator shapes are possible.

Resonator ladder surface acoustic wave filter suppressing spurious signals

Abstract: A resonator ladder surface acoustic wave (SAW) filter, which has a wide and flat pass band without spurious signals therein is provided. An input electrode, a serial arm SAW resonator, an output electrode, a parallel arm SAW resonator and a ground electrode are respectively formed on a 41°-rotated Y-cut X-propagation lithium niobate substrate. The serial arm SAW resonator comprises a pair of interdigital transducers (IDTs) to excite SAW, one of which is connected to the input electrode. The output electrode is connected to the other IDT of the serial arm SAW resonator. The parallel arm SAW resonator comprises a pair of IDTs to excite SAW, one of which is connected to the output electrode. And the ground electrode is connected to the other IDT of the parallel arm SAW resonator. The IDTs are metal films of Al or Al-based alloy, and the thickness of the metal films ranges from 2.5% to 7.5% of the electrode cycle of the IDT of the parallel arm SAW resonator.

Dielectric resonator, and microwave filter provided therewith

Abstract: In a dielectric resonator a dielectric insert is formed so that at least two slots are provided, which are located opposite to one another and extend symmetrically and radially toward a center. Because of the radial slots, a dielectric resonator with high mode distance and high quality is obtained.

Dielectric resonator capable of varying resonant frequency

Abstract: A dielectric resonator capable of adjusting a resonance frequency, reducing occurrence of a mode jump if it is applied to an oscillator and being manufactured at a low cost. The dielectric resonator has a pair of upper and lower opposing conductive plates; a dielectric substrate disposed between the conductive plates; a first electrode formed on one surface of the dielectric substrate, the first electrode having a first opening; a second electrode formed on another surface of the dielectric substrate, the second electrode having a second opening corresponding to the first opening so that a resonator is formed by a portion of the dielectric substrate disposed between the first and second openings; and a variable capacitor located in a portion of the dielectric substrate in which an applied electromagnetic field is confined in and around the resonator.

Noiseless radar detector

Abstract: A noiseless radar detector with a dielectric resonator to suppress stray electromagnetic radiation generated by a local oscillator within the radar detector is disclosed. The dielectric resonator acts as an RF microwave absorber/attenuator if the resonant frequency of the dielectric resonator corresponds to the frequency of the interference from the local oscillator.

Dielectric filter and antenna duplexer

Abstract: A dielectric filter includes a dielectric block on which an external conductor is formed except for areas surrounding input and output terminals, a plurality of resonator holes of the same axial length, and input and output external coupling bores. The resonator holes and input and output external coupling bores are formed substantially in parallel with each other between a pair of opposing end faces of the dielectric block. The resonator holes are provided with internal conductors except for dielectric bases in the vicinity of openings thereof. The internal conductors are connected to the external conductor at the pair of end faces so that resonators having specific resonator lengths are constituted by the positions of open ends thereof formed by the dielectric bases. The input and output external coupling bores are provided with internal conductors. The internal conductors are connected to the external conductor at one end face of the dielectric block and connected to the input and output terminals at the other end face of the dielectric block. Corresponding features are provided in an antenna duplexer.

Dielectric resonator apparatus with magnetic field coupling loop

Abstract: A dielectric resonator apparatus includes a plurality of TM double-mode dielectric resonators. Each dielectric resonator has a dielectric rod-complex, a casing provided with electrically conductive film at the outside surfaces, and metal panels covering the upper and lower openings of the casing. In adjacent TM double-mode dielectric resonators, at portions of the planes of the two casings opposing each other, apertures are provided in the direction of the magnetic field generated by two dielectric rods which have the same axial direction. A coupling member is also provided so as to form an electrically conductive loop which goes across the magnetic field.

Small eletric monopole mode dielectric resonator antenna

Abstract: A novel dielectric resonator (DR) antenna is reported The lowest order mode of the proposed antenna radiates like an electric monopole The dimensions of the antenna are much smaller than a previously reported structure radiating in a similar mode, eg for an antenna fabricated out of /spl epsi//sub r/=20 material, the diameter and height of the DR are /spl sim/008 /spl lambda//sub 0/ each

Surface acoustic wave filter utilizing a transducer having interdigital electrodes and continuously adjacent electrodes

Abstract: A surface acoustic wave filter according to the present invention has one or a plurality of filter functional units each comprising a series arm resonator and a parallel arm resonator. Each of the series arm resonator and the parallel arm resonator is constituted by a interdigital transducer and grating reflectors formed on a piezoelectric substrate composed of 64°-rotated Y-cut X-propagating LiNbO 3 . The series arm resonator is constructed by electrically connecting a one-port resonator in series with a signal line, and the parallel arm resonator is constructed by electrically connecting a one-port resonator in parallel with the signal line. In the interdigital transducer in the series arm resonator and/or the parallel arm resonator, one or more sets of electrode fingers continuously adjacent to each other are formed.

Surface acoustic wave device having one-port and double mode SAW resonators

Abstract: A surface acoustic wave device which not only is low-loss in a pass band and has high attenuation in an attenuation region but also has superior power-resistance and has a large reflection coefficient in a blocking region comprises a first one-port SAW resonator filter connected in parallel with a three-electrode vertically connected double mode SAW resonator filter. The first one-port SAW resonator filter is so constructed that its resonance frequency is outside the pass band of the vertically connected double mode SAW resonator filter on the low-frequency side thereof and a connection point between the double mode SAW resonator filter and the first one-port SAW resonator filter is provided to an input terminal.