Showing papers on "Dielectric resonator antenna published in 1974"

A stripline resonator for ESR

Abstract: A stripline resonator for ESR is described. Spectra obtained show that the relatively low Q value, as compared with a standard cavity, is to a high degree compensated by the higher filling factor. The same resonator can be used for different frequencies. At low ESR frequencies the size of the resonator is much smaller than that of a cavity. A possibility of obtaining circularly polarized radiation is pointed out.

Filter for electromagnetic waves

Abstract: A plural circuit filter for electromagnetic waves, especially microwaves, of the type which comprises dielectric resonators, is provided wherein dielectric resonator disks or washers are positioned in a tubular metallic housing acting as a shield, the resonator disks being positioned centrally of the housing tube with the axes of the disks extending perpendicularly to the axis of the tube and the separate resonator disks being separated in the housing by apertured partitions which partly determine the coupling coefficient between adjacent circuits.

Cylindrical laser resonator

Abstract: The properties of an improved class of lasers is presented. In one configuration of these lasers the radiation propagates radially within the amplifying medium, resulting in high fields and symmetric illumination at the resonator axis. Thus there is a strong focusing of energy at the axis of the resonator. In a second configuration the radiation propagates back and forth in a tubular region of space.

Method of assembly of crystal filters

Abstract: In this filter, each one of two coupled resonators is formed on a different crystal wafer. Each wafer is accurately positioned with respect to one longitudinal groove in the periphery of a ceramic ring. The wafer is supported in the central opening in the ring with wires which are soldered to metalized areas of the ring and to resonator lead patterns on the wafer to form a resonator assembly. Each resonator is tuned to operate at a predetermined frequency by locating the associated resonator assembly in a masking jig with respect to the one groove on the ring to accurately align the resonator electrode patterns with holes in the jig. A metal film is evaporated onto a resonator electrode to adjust the resonant frequency of the associated resonator to be equal to the predetermined frequency. In a packaged filter the resonator assemblies and electrically conductive spacers are alternately stacked on a header having a pair of posts protruding therefrom that are located in longitudinal grooves in the ceramic rings and openings in the spacers for supporting the stacked elements. Extensions and tabs on the spacers are soldered to the alignment posts and metalized areas on the rings, respectively, to ground the resonators and spacers to the header. The spacer sandwiched between the rings provides isolation between the resonators on adjacent wafers. A discrete chip capacitor is connected to a resonator electrode and a metalized area on a ring which is grounded to the header. The resonator electrodes are also selectively interconnected and connected to insulated lead pins in the header to produce a filter structure. The packaged filter is hermetically sealed by cold welding a cover to the header.

Dielectric apparatus and method utilizing resonance for humidity measurement

Abstract: Apparatus for humidity measurement employing a dielectric resonator consisting essentially of a metallic guard, a solid dielectric material, an input antenna and an output antenna. Method of measuring humidity comprising feeding a microwave energy of swept frequencies to the input antenna of said appratus, recovering said energy as a microwave power from the output antenna, and then determining the humidity of the gas through which the microwave energy travels from one antenna to the other, the value of humidity being based on the frequency characteristic of said microwave power.

Microwave tube using electronically tunable cavity resonator

Abstract: A microwave cavity resonator, such as the circular electric mode resonator of a coaxial magnetron, is electronically tuned by coupling an electronically tunable array of reactive loading elements to the resonator. Tuning means, such as PIN diodes or ferrite tuning members, are associated with respective ones of the reactive loading elements for varying the reactive loading effect of respective ones of said reactive loading elements on the composite resonator for tuning the resonant frequency of the composite resonator in accordance with the reactive loading effect of the elements. In a preferred embodiment, the reactive loading structure is preferably disposed inside of the resonator. In the case of a circular electric mode resonator, the individual reactive loading elements are preferably energized in a symmetrical manner relative to the resonator to avoid converting energy from the circular electric mode to certain other unwanted lower Q modes.

Piezoelectric ceramic resonator mounting means

Abstract: A piezoelectric ceramic resonator to be used for an electric wave filter or an impedance transformer, and a manufacturing method of the ceramic resonator of the above described type, is provided in which a piezoelectric ceramic wafer, held at nodes or points close to the nodes of the electrodes of the wafer between outer terminal plates, is dipped in a melt, or the like, of gap-forming materials to form a first layer of such materials on the resonator with a second layer of porous thermosetting resinous material formed on the surface of the first layer. The gap-forming materials forming the first layer is subsequently sublimated or evaporated and absorbed into the second layer to form a space between the resonator and the second layer with the resonator advantageously surrounded by the space for stable vibration.

Miniature crystalline laser

Abstract: An optically pumped crystalline laser that includes a small single crystal section of a polygonal cylinder; the dimensions of the crystal section and the index of refraction of the crystal and the medium surrounding the crystal are such that there is formed a dielectric resonator that is totally reflective for a small number of modes. The material of which the crystal section is composed is one that is capable of being made optically thick in thin sections. The resonator is optically pumped and the lasing radiation therein is coupled to an optical element that is placed in close proximity thereto by virtue of an evanescent field that arises from the lasing action in the resonator.

Stabilized microstrip oscillator using a temperature-stable dielectric resonator

Abstract: A temperature-stable high-Q dielectric resonator, developed for microstrip circuits, and used to stabilize the microstrip oscillator, will be described.

Electronic frequency selector

Abstract: An adjustable electronic frequency selector which comprises a block of high-resistivity bulk single crystal intrinsic semiconductor forming a low-loss cavity resonator for millimeter and submillimeter waves, and control means which includes either a semiconductor appendage mounted to one major surface of said semiconductor resonator block in which is formed doped regions of opposite conductivity type or which includes doped regions of opposite conductivity type formed within a portion of said resonator block adjacent either one major surface or formed within two juxtaposed major surfaces of said portion of the resonator block. A variable unidirectional forward biasing voltage source is connected across said doped regions of opposite conductivity type. The lowest frequency of resonance, as well as the frequency separation between possible operating frequencies of said resonator, depends, in part, upon the length of the semiconductor cavity resonator block. The frequency separation also is a function of the effective dielectric constant of the resonator block. The frequency separation can be electronically adjusted by varying the aforesaid forward biasing voltage to control the concentration of carriers injected into one major surface of the resonator block or the appendage thereto, as the case may be.

New rotating-field resonator for lasers

Abstract: A new type of laser resonator is proposed: It is a ring resonator with a rotating field. It differs from other types of resonator by the rotation of the electromagnetic field through some angle after each pass to the active medium. This rotation ensures averaging of the transverse optical inhomogeneity in the laser resonator. Such averaging is demonstrated for a ruby laser. The proposed resonator can be used in other types of laser with inhomogeneous active media.

Multiple frequency flexure-mode resonator

Abstract: A flexure-mode resonator employs a plurality of switchable piezoelectric transducers which can be shorted out individually or in combination to provide multiple operating frequencies.

The use of the open spherical resonator as the sampling cavity in a microwave radio refractometer

Abstract: Details are given of measurements made on open spherical X-band resonators suitable for use as the sampling cavity in a microwave radio refractometer. The resonators, with dimensions comparable to a wavelength, have loaded Q's in the region of 104. A resonator, constructed of brass spherical reflectors and silica spacing rods resonating at 10.5 GHz, has a temperature coefficient of 0.5 N units/ degrees C and an open area to volume ratio of 1 cm-1. Results indicate that this resonator, because of its relatively large open area, allows a much faster change of atmospheric content than the conventional TE011 resonator with open end plates.

High q band-pass resonators utilizing composite band-stop resonator pairs

Abstract: Resonator pairs are formed of composite series- or parallel-connected transmission-line elements, which are exclusively quarter-wavelength half-wave-length lines. Resonator elements are constructed with microstriplines in parallel planes separated by dielectric. Striplines of coaxial transmission lines can be used in construction also.

Field analysis and complex resonance frequency of the quasi-TE0,1,1-mode in an inhomogeneously filled resonator with losses

Abstract: The object of the present investigation is the determination of the field intensity and the resonance frequency of the quasi-TE0,1,1-mode (with rotational symmetry) in an inhomogeneously filled resonator. The resonator is filled with a number of concentrically located tubes consisting of different materials, which may be lossy. The top and the bottom walls of the resonator are electrically perfectly conducting; at the side wall an impedance boundary condition is employed. Numerical results for a case of practical interest in magnetic resonance experiments are obtained.

Microwave dielectric resonator-tuning

Abstract: : Dielectric resonators have applications as low-loss compact filters in the microwave region Tuning characteristics of dielectric resonators that might allow for temperature compensation and frequency variability were investigated both theoretically and experimentally at L band A secondary dielectric resonator that is offset in frequency from the tuned resonator provides a maximum tuning range of approximately 10 percent before an additional filter loss of 3 dB is incurred; the rate of tuning is slow since it is done by changing the resonator coupling (spacing) For fast tuning, a varactor is used in a coupled resonant circuit Frequency changes can then be made in a time interval approaching 1/(filter bandwidth), but in this case the maximum tuning range before an additional filter loss of 3 dB is incurred is reduced to 2 percent of the filter frequency