Showing papers on "Dielectric resonator antenna published in 1987"

Measurement of the Dielectric Properties of Biological Substances Using an Improved Open-Ended Coaxial Line Resonator Method

Abstract: An improved open-ended coaxial line resonator method for measuring the complex permittivity of biological substances is presented. By considering the end radiation losses and higher order mode effects, the upper frequency limit is extended from 4 GHz to 11 GHz. A novel lambda/4 open-ended coaxial line resonator, which uses a thin copper diaphragm for a coupling structure, was developed. Experiments show that the structure is very flexible, convenient, and reliable. Experimental results for several canine organs as well as human skin are given. The method has useful applications to microwave medicine and bioelectromagnetic studies.

Monolithic microwave transmitter/receiver

Abstract: Preferred embodiments include a microstrip patch antenna (38) which also acts as the resonator for an oscillator powered by IMPATT diodes (34, 36); this forms a monolithic transmitter (30) for microwave and millimeter wave frequencies.

Dielectric High-Power Bandpass Filter Using Quarter-Cut TE/018/ Image Resonator for Cellular Base Stations

Abstract: A dielectric high-power bandpass filter using "quarter-cut TE/sub 01delta/ image resonators" has been developed. The resonator has a high unloaded Q over 7000 and its construction provides a sufficient thermal diffusion path to the metal housing. The insertion loss and the attenuation level of the eight-pole elliptic function type filter are 0.37 dB and 95 dB, respectively. The physical size of the dielectric filter is 280x135x 65 mm, one third to one fifth the volume of conventional cavity resonator filters.

Apparatus for microwave heating of ceramic

Abstract: An apparatus for heating a ceramic by microwave power. The apparatus has a cavity resonator in which the ceramic is placed. The resonator is provided with a variable iris. The apparatus detects the temperature of the ceramic or other state of the ceramic, and adjusts the area of the opening in the iris in the resonator and the resonant frequency of the resonator according to the signal produced by the detection, in order to bring the resonator substantially into resonance and the degree of coupling to exactly or nearly unity. Alternatively, the apparatus adjusts its microwave power for these purposes. The apparatus can heat the ceramic efficiently at a desired heating rate.

Canonical Bandpass Filters Using Dual-Mode Dielectric Resonators

Abstract: A canonical bandpass filter constructed by placing dual-mode dielectric resonators coaxially in a cutoff circular waveguide is discussed Rigorous analysis of the dual-mode dielectric resonator and inter-resonator coupling is performed with the mode matching technique Four- and six-pole elliptic bandpass filters are realized at 12 GHz

Radiation characteristics of the short dielectric rod antenna: A numerical solution

Abstract: The problem of the dielectric rod antenna is studied numerically. The surface integral equation is used to simulate the problem in its actual form. From the surface currents induced on the antenna surface, the far-field radiation patterns are calculated. Different parameters are considered, such as the extension of the dielectric from the waveguide aperture, the waveguide and the dielectric diameter, the dielectric constant and finally the effect of shaping of the dielectric end. The performance of the antenna as a feed for the reflector antenna is also studied by calculating the gain factor, spillover efficiency and the phase center location of the feed. Some of the results are compared with the available experimental data of Dombek. The agreement is found to be excellent.

Stripline filter with improved resonator structure

Abstract: A stripline filter resonator structure is provided which exhibits high Q and results in a filter with low insertion loss The dielectric consists of two sections of dielectric material A groove shaped as half an ellipse is formed in each of the sections The surface of the grooves are covered with electrically conductive material The two grooves are aligned and filled with adhesive material to hold the two dielectric sections together An elliptically shaped resonator is thus formed in the center of the dielectric sandwich Ground plane layers are respectively situated on the outer layers of the dielectric sandwich thus forming a stripline resonator structure This unique resonator structure results in a more uniform current density around the periphery and thus undesired current bunching is correspondingly decreased

Resonant frequencies of whispering-gallery dielectric resonator modes

Abstract: Whispering-gallery dielectric resonator modes have shown their usefulness in millimetre wave integrated circuits. In the paper, a method for the determination of the resonant frequencies of the whispering-gallery modes of cylindrical dielectric resonators is presented. Theoretical and experimental results are given. A comparison with other methods is also made.

Accurate prediction of radiation patterns of dielectric resonator antennas

Abstract: The radiation patterns of cylindrical dielectric resonator antennas excited with a TM11 mode is computed numerically. The numerical data obtained is found in good agreement with available experimental results. The symmetry of the radiation patterns is improved by reducing the ground plane dimensions, while the backlobe level is reduced by placing the antenna in a topless cylindrical cavity.

Solid state optical ring resonator and laser using same

Abstract: In a monolithic optical ring resonator an optically transparent member is faceted so that the input and output beams of the resonator are coupled through a common facet at widely divergent angles in excess of 45 degrees and preferably 90 degrees. In this manner the resonator is miniaturized. The ring resonator member is contained in an evacuated housing to eliminate time-varying convective thermal detuning effects. The ring resonator is coupled in heat-exchanging relation with heating and temperature sensing film resistors deposited upon a major face of a substrate member.

Dielectric resonator electromagnetic wave filter

Abstract: A dielectric resonance electromagnetic filter for selection of a resonance frequency of a high frequency electromagnetic wave having the dielectric resonator attached directly to the shield. The filter is tunable using a tuning cylinder which moves through a cavity in the center of the resonator. The tuning cylinder is hollow and is designed to expand thermally during heatup to counter thermal changes in the resonance frequency. The tuning cylinder may be metal or dielectric material or may have sections of both materials. A shield geometry has been described which enables filter clusters to occupy a minimum volume.

Resonator pressure transducer structure and method of manufacture

Abstract: A quartz resonator pressure transducer includes a generally disc-shaped resonator section adapted to vibrate in response to an oscillatory signal, a housing having sidewalls which generally circumscribe the resonator section and extend in opposite directions generally normal to the plane of the resonator section, and a web, thinner than the resonator section, joining the housing to the perimeter of the resonator section to define grooves between the sidewalls of the housing and the resonator section on the top and bottom sides of the section.

Ceramic TEM resonator bandpass filters with varactor tuning

Abstract: A ceramic TEM resonator bandpass filter with varactor tuning is disclosed. The varactor is located within the resonator holes of a ceramic TEM resonator filter, and is positioned within said holes immediately above the upper extent of the metal plating forming the resonator in said resonator holes. The placement of the varactor in such a manner reduces the interference caused by the varactor in the interresonator coupling. A new apparatus for positioning the varactor within the resonator hole is disclosed and basically includes a conductive rod which at its top end receives the varactor.

SAW resonator and resonator filter on Li2B4O7 substrate

Abstract: Lithium tetraborate (Li2B4O7) single crystal has attracted attention as a piezoelectric substrate for SAW devices. This paper focuses on its application to a SAW resonator. Reflection characteristics for aluminum strips and configuration suppressing surface-to-bulk-wave conversion are discussed. Results prove that the strips on Li2B4O7 substrate reflect efficiently, compared with those on the other substrates, and that a newly developed configuration improves the resonator Q at least twice. Further, a low insertion loss of 2.5 dB is achieved for a paging receiver filter.

Method for reading out rotation rate with a passive optical resonator

Abstract: A rotation rate readout method employing a passive optical resonator. The ring resonator is operated at approximate resonance in reflection and rotation rate-dependent phase shifts are detected, in particular as first harmonics, in the resonator. Two partial light beams are first frequency shifted by equal and opposite amounts, such frequency shift being modulated. Light components coupled out of the resonator pass through a mode filter in the opposite direction and are detected as an interference signal by an opto-electronic converter. The latter signal is demodulated with respect to the modulation frequency or its harmonics and the rotation rate signal obtained therefrom. Self-compensation of the optical and electronic readout systems may be attained by periodic brief and strong damping of the ring resonator. In contrast with known methods wherein two channels are separately processed and two mode filters required, the interference signal is processed in accordance with the invention requiring only a single mode filter.

Method and apparatus for the measurement of the properties of sheet- or foil-like materials of low electrical conductivity

Abstract: A measurement method and an apparatus are used for determining the moisture content of sheet- or foil-like materials (1) of high moisture content and low electrical conductivity. Ground planes (3) are adapted on both sides of the material (1) to be measured; between each ground plane (3) and the material (1) to be measured, at least one center conductor (2) is adapted approximately parallel to the material (1) to be measured in order to form a quasi-TEM transmission line resonator. Electromagnetic RF energy is fed into the quasi-TEM transmission line resonator so that the electromagnetic quasi-TEM waves propagate in the plane of the material (1) to be measured. The resonator supports for the transverse and longitudinal waves such resonant modes whose resonant frequencies and Q's are dependent on the properties of the material (1) to be measured. The resonant frequencies and related Q's are measured, and these are used for determining the complex dielectric constant of the material (1) to be measured or, alternatively, the characteristics related to them.

Dielectric resonator for microwave band

Abstract: A resonator for microwave or VHF-UHF bands has a ring dielectric plate, one surface of which is metalized to make a resonant line, and at least one of other surfaces of which is also metalized to make a grounded or earth conductor. The resonator is very small in size and has a large unloaded Q value. Several embodiments are disclosed.

Coupled resonator phase shift oscillator

Abstract: A phase shift oscillator formed with a surface acoustic wave coupled resonator in series with an amplifier and wherein the coupled resonator has a substantially 180° phase shift occurring between the 3dB points of the frequency response curve of the coupled resonator

Multi-frequency dielectric resonator oscillator using parallel feedback

Abstract: A switchable, parallel-feedback, multi-frequency dielectric resonator oscillator that generates microwave energy at any of several available frequencies is disclosed. The oscillator includes an amplifier that is operable for oscillation at a frequency determined by a parallel feedback dielectric resonator connected between its output and input terminals, and a switching circuit for selectively connecting any one of a plurality of dielectric resonators to the input terminal of the amplifier. The oscillation frequency of the oscillator is determined by a resonant frequency of whichever of the dielectric resonators is connected to the input terminal of the amplifier through the switching circuit.

Dielectric resonator frequency discriminator for stabilizing oscillator frequency

Abstract: A frequency discriminator (1) stabilizes a voltage controlled oscillator (5), particularly one operating at microwave frequencies. A single dielectric resonator (2), typically positioned within a housing (8), is excited by an r.f. input (30). The dielectric resonator (2) generates in response to the excitation first and second orthogonal modes of r.f. electromagnetic energy at slightly different frequencies. The two orthogonal modes are converted to d.c. output signals (39, 40) of opposite polarity and substantially the same magnitude, e.g., by diodes (35, 36). Frequency offsets are obtained by tuning screws (43, 44) and/or by changing the amount of dielectric (2) in the path of the characterizing vector corresponding to the mode being frequency-offset.

Measurements and Analysis of Cryogenic Sapphire Dielectric Resonators and DRO's

Abstract: Presented are the experimental and computational results of a study on a new kind of dielectric resonator oscillator (DRO). It consists of a cooled, cylindrically symmetric sapphire resonator surrounded by a metallic shield and is capable of higher Q's than any other dielectric resonator. Isolation of fields to the sapphire by the special nature of the electromagnetic mode allows the very low loss of the sapphire itself to be expressed. Calculations show that the plethora of modes in such resonators can be effectively reduced through the use of a ring resonator with appropriate dimensions. Experimental results show Q's ranging from 3 x 10 to the 8th at 77 K to 10 to the 9th at 4.2 K. Performance is estimated for several types of DROs incorporating these resonators. Phase noise reductions in X-band sources are indicated at values substantially lower than those previously available.

Mode matching method for determination of the resonant frequency of a dielectric resonator placed in a metallic box

Abstract: A method for the determination of the resonant frequency of a cylindrical dielectric resonator inserted into a cylindrical metallic box is presented. The method can be applied to asymmetrical structures.

High frequency resonator for welding material

Abstract: A blade-shaped high frequency resonator for welding sheet material without a gap, when resonators of this shape are disposed in an array, includes at its output surface a pair of laterally extending ears, each ear terminating in end surfaces configured to interface with the end surfaces of a similarly shaped juxtaposed resonator. Each ear is dimensioned to cause the sum of the moments about the lateral axis of the resonator to be substantially zero. Typically, the lateral end surface of a respective ear is of a zigzag configuration. The end surface intersecting the lateral resonator axis intersects such axis at an angle of less than ninety degrees.

Confocal Fabry-Perot microwave resonator at 48 GHz for high-resolution spectroscopy

Abstract: A high-Q confocal Fabry-Perot microwave resonator for precision spectroscopy of atoms, ions and molecules is described, giving convenient access to the overlap region of interacting species, microwave field and light. Microwave power is coupled with almost 100% efficiency into the interferometer by means of a small copper wire dipole antenna. The concept of an uncomplicated and inexpensive frequency stabilisation of microwave sources through coupling to a Fabry-Perot reference resonator is discussed.

Optically stable resonator for producing a laser beam

Abstract: An optically stable resonator producing a laser beam which by the use of a converging and of a diverging optical element is subdivided into an amplifier part with large beam diameter and small energy density and into a mode filter part with small beam cross section and correspondingly small Fresnel number all with a short structural length of the resonator. The advantage of the present invention resides in the high beam quality of the produced beam which contains predominantly only the fundamental mode, and in the small thermal load of the participating elements, especially of the decoupling window. The subdivision of the stable resonator according to this invention into an amplifier part and into a load filter part opens up to this resonator type power output ranges which were precluded heretofore by reason of a maximum permissive thermal load of the decoupling window.

Device and method for detecting conductive material in nonconductive fiber

Abstract: PURPOSE: To permit sure detection of a conductive material by providing a through-hole to the central part of a re-entrant cylindrical cavity resonator connected to a microwave oscillator, passing a specimen which is a nonconductive fier into the through-hole and discriminating the change in resonance conditions CONSTITUTION: The through-hole 12 into which yarn 13 is passed is provided to the central part of the re-entrant cylindrical cavity resonator 11 and the resonator 11 is connected via an input/output terminal 23 mounted on the outside wall part thereof and a circulator 24 to the microwave oscillator 16 The output of the resonator 11 is supplied via an A/D converter 26 to a CPU 18; on the other hand, the output for controlling the oscillation frequency of an oscillator 16 is transmitted via a D/A converter 27 The amplitude of the output does not change and the resonance frequency shifts largely when there is a very small metal in the yarn 13; therefore, whether the conductive foreign matter is moisture or metallic foreign matter is identifiable if the discrimination as to whether the output drop of the resonator 11 is by a change in the resonance frequency or is the mere change in the amplitude is made COPYRIGHT: (C)1988,JPO&Japio

Method of precisely adjusting the frequency of a piezoelectric resonator

Abstract: The frequency of a piezoelectric resonator is precisely adjusted using monomolecular layer(s) of a thermally stable, low stress, uniform insulating film deposited on the active area of the resonator. The method is particularly suitable for precisely adjusting the frequencies of high frequency (i.e., very thin) resonators, and the frequencies of lateral field resonators, without degrading stability.