Showing papers on "Dielectric resonator antenna published in 1988"

Microstrip transmission line excitation of dielectric resonator antennas

Abstract: A systematic investigation of the excitation of a cylindrical dielectric resonator antenna was undertaken to illustrate the possibility of such a feed structure and to characterise the coupling behaviour and radiation patterns of the system.

Attenuation measurement of very low loss dielectric waveguides by the cavity resonator method applicable in the millimeter/submillimeter wavelength range

Abstract: A dielectric waveguide shorted at both ends was constructed as a cavity resonator. By measuring the Q of this cavity, one can determine the attenuation constant of this guided mode on this dielectric structure. The complex permittivity of the dielectric waveguide material can also be derived from the measurements. Measurements were made at Ka-band for dielectric waveguides constructed of nonpolar, low-loss polymers, such as Teflon, polypropylene, polyethylene, polystyrene, and rexolite. >

Dielectric resonator apparatus

Abstract: The dielectric resonator apparatus is characterized in that electric walls exist on one plane or two including the central axis of the electromagnetic field distribution in the using mode of a dielectric resonator, a dielectric resonator with either of dielectrics between the electric wall being removed in shape is provided by plurality, an equivalent axis is common to the central axis of each of the dielectric resonators, with the dielectric resonators being inductively coupled in the axial direction. A dielectric resonator which prevents the current from being concentrated on the central axis of the electromagnetic field distribution, is collectively smaller in the Joule loss and is higher in Q. The dielectric resonator of the present invention is characterized in that the dielectric close to the central axis is removed, wherein electric walls exist on one plane or two including the central axis of the electromagnetic field distribution in a dielectric resonator using, for instance, a TE01δ mode, with either of dielectrics between the electric wall being removed in shape.

Bridged loop–gap resonator: A resonant structure for pulsed ESR transparent to high‐frequency radiation

Abstract: A new and inexpensive X‐band resonator structure for pulsed electron‐spin resonance and electron‐nuclear‐double‐resonance applications is introduced The resonator consists of a bridged loop structure and is distinguished by a good reproducibility and reliability It has a high filling factor and an adjustable Q value and is transparent to radio frequency fields with an upper limit >100 MHz The inner diameter of 5 mm allows convenient sample access of standard 4‐mm quartz tubes in the temperature range between 4 and 300 K Numerical computations of the resonant frequencies, the Q values, and the three‐dimensional distributions of the electromagnetic fields are presented They are based on a discretization method for the solution of Maxwell’s equations and include all dielectric elements of the resonator structure The field homogeneity in the sample area and the influence of the dimensions and the thickness of the metallic layers on field intensity, quality factor, and resonant frequency are determined e

Direct-coupling single-mode fiber ring resonator

Abstract: A single-mode resonator is constructed by joining together the ends of the coupled fiber of a 2 × 2 directional single-mode optical fiber coupler. Analytical expressions are obtained for the resonance conditions. The effects of different kinds of losses are investigated. The variation of the phase at resonance and the problem of mismatch are discussed. A formula for the finesse of the resonator is also given. Unlike reentry fiber resonators, this kind of resonator needs a directional coupler with only a small coupling coefficient. It is possible to achieve a high finesse and symmetrical outputs. Applications of such a resonator are discussed.

Efficient laser harmonic generation employing a low-loss external optical resonator

Abstract: TEM OOq laser radiation derived from a diode-pumped ring laser is directed into a faceted member of nonlinear optical material defining either a standing wave or ring monolithic optical resonator to generate harmonic laser radiation. The losses of the optical resonator, exclusive of the conversion loss to the harmonic, are made sufficiently low such that the dominant loss presented to the resonated mode of the optical resonator is the conversion loss to the generated harmonic. The reflectance of the input mirror of the optical resonator is impedance matched to the losses of the resonator including the harmonic conversion loss for optimum conversion efficiency. The length of the nonlinear optical material is shortened to the point where the bulk losses are less than ten times the sum of the surface and mirror losses, yielding conversion efficiencies of greater than 20 percent.

A transmission line resonator

Abstract: The invention relates to a resonator structure comprising a helix resonator (1) wound of metal wire into a cylindrical coil and supported by a plate (2) of insulating material disposed therewithin. A helix resonator is usually made in the form of a cylindrical coil and supported by disposing within the coil a frame made of a ceramic material or plastic in various ways. This is necessary for providing a sufficient mechanical strength. However, such a structure is difficult and expensive to manufacture in series production especially with smaller resonator sizes. These problems are solved by means of a resonator according to the invention in such a manner that at least a part of the insulating plate (2) comprises an electrical circuit formed by strip lines (3), and that the helix resonator (1) is electrically connected to said circuit.

Suppression of bulk-scattering loss in SAW resonator with quasi-constant acoustic reflection periodicity

Abstract: The author proposes a SAW (surface acoustic wave) resonator structure which suppresses the bulk-scattering loss for a high reflectivity resonator. The approach uses an effective configuration to cancel the scattered radiation bulk waves from the GRs (grating reflectors) and the IDT (interdigital transducer) simultaneously. It consists of an IDT and metal-strip GRs, which are of the same material and which have the same thickness. The distance between the IDT and the GR is set to be a half-wavelength and the pitch for the IDT electrodes is slightly shortened to tune to the resonance condition. The structure realizes quasiconstant acoustic reflection periodicity (QARP) all over the resonator. The QARP structure was shown to suppress the mode conversion loss and to improve the resonator Q-factor. Experimental results provide that the QARP structure led to a two-fold improvement of the Q-factor for the high reflectivity resonator. Furthermore, theoretical analysis also proved that the scattered bulk waves were suppressed to less than 1/100 in the QARP-structured SAW resonator. >

Dielectric notch filter

Abstract: A dielectric notch filter for attenuating frequencies of relatively narrow bandwidth in comparison to the center frequency of operation, and particularly for attenuating such narrow bandwidths in the ultra-high frequency electromagnetic spectrum. The dielectric notch filter comprises a plurality of dielectric notch resonators coupled to a transmission line at slightly less than the quarter wavelength of the center frequency of the attenuation frequency bandwidth so as to minimize interaction between the individual dielectric notch resonators. Each dielectric notch resonator comprises a dielectric resonator, an associated housing and a coupling reactance element which in turn comprises an inductive wire and a variable capacitor so as to null the reactive component of the dielectric resonator, thereby resulting in a highly attenuated resonant frequency having little imaginary component about said center frequency. By use of a plurality of such dielectric notch resonators, a bandwidth of frequencies can be attenuated through coupling of each resonator to the transmission line.

Precise Measurement Method for Complex Permittivity of Microwave Dielectric Substrate

Abstract: A new technique for the measurement of the complex permittivity of dielectrie substrates using a dielectric resonator is reported. This method is a non-contact measurement using two dielectric resonators which support TE mode. This paper describes some examples of measurements.

Low power transmitter frequency stabilization

Abstract: An improved miniature hand-held low power transmitter utilizing a surface acoustic wave (SAW) resonator as the control element to establish the carrier frequency of the oscillator. The SAW resonator stabilizes the frequency of the transmitter to within 0.05% of the center frequency of the SAW resonator for the condition of the user's hand enclosing the transmitter. This stability allows the companion receiver to operate at a narrow bandwidth, 0.1% of the center frequency of the SAW resonator, thus reducing the spurious noise received by the receiver. The configuration of the transmitter allows schemes such as pulse position or pulse width modulation to be utilized to encode the transmitted information. The physical size of the SAW resonator allows the transmitter to be mounted within a housing small enough to be enclosed by the user's hand.

Tunable microwave filtering device with dielectric resonator, and applications

Abstract: A tunable, microwave filtering device comprises a microstrip line, a dielectric resonator capable of being coupled to the microstrip line, a coplanar line capable of being coupled to the resonator, an active element, such as a varactor for example, mounted on the coplanar line, the variable impedance of which enables the frequency tuning of the device. The invention can be applied to the making of a tunable microwave frequency discriminator, the making of a microwave oscillator and the frequency stabilization of a tunable oscillator.

A generalization of the self-filtering unstable resonator

Abstract: Calculations on a generalization of the self-filtering unstable resonator (SFUR) are presented. The resonator is no longer confocal, and in principle, may have a shorter cavity length, while the other properties remain almost the same. >

Method for frequency stabilization of a semiconductor laser comprising a coupled external ring resonator

Abstract: A method for frequency stabilization of a semiconductor laser having a coupled, external ring resonator, which stabilizes the emission frequency of the semiconductor utilizes a stabilizing of the free spectral range and the resonant frequencies of the ring resonator in order to correct for changes due to temperature fluctuations. To accomplish this, a shift in resonant frequency from a predetermined value and a shift in the free spectral range from a rated value is compensated by utilizing a phase modulator to act on the resonator to shift the frequencies back to the predetermined frequencies.

Electronically tuned dielectric resonator stabilized oscillator

Abstract: An electronically tuned dielectric resonator stabilized oscillator has a dielectric resonator that is fine tuned by an electronic method of tuning which includes a varactor coupled to a microstrip. This varactor microstrip transmission line is positioned below the dielectric resonator but above the plane in which a transmission line for the carrier frequency resides. By not placing the fine tuning microstrip line on the same plane as the main oscillator line, spurious oscillation between the fine tuning transmission line and the primary carrier wave resonator frequency line are minimized. Additionally, the fine tuning microstrip line is positioned orthogonal to the pathways along which the main signal transmission lines are coupled.

Dielectric notch resonator

Abstract: A dielectric notch resonator particularly suitable for use in a band reject filter operable at ultra-high frequencies comprises a dielectric resonator and an associated housing which results in a reactance having an imaginary component effectively nulled by a coupling reactance mechanism forming part of the dielectric notch resonator so as to present a relatively low resistive impedance load at a given center frequency and frequencies in a narrow bandwidth thereabout. The coupling reactive mechanism comprises an inductive wire and a serially connected variable capacitor so as to null the reactive component of the dielectric resonator at a particular center frequency and to modify the symmetry of the rejected frequency bandwidth by adjusting the capacitance of the variable capacitor.

Microwave resonator for operation in the whispering-gallery mode

Abstract: A microwave resonator for operation in the whispering-gallery mode is constituted by a resonant element included in a flat disk having a diameter (2a) which is considerably larger than its thickness (2d). An electromagnetic wave which propagates within the disk is confined between the periphery of this latter and a so-called caustic surface having a smaller radius (a c ). The wave does not radiate to the exterior and the resonator can be placed on a dielectric or metallic substrate. The disk can be hollowed-out within the caustic surface. A resonator can be simulated within the thickness of a dielectric substrate by at least one metallic ring which forms a magnetic short-circuit with the ground plane. Excitation is produced by microstrips or by dielectric image waveguides.

Quasi-Optical Resonator Far Millimeter And Submillimeter Wave Solid-State Sources

Abstract: A new cavity for millimeter and submillimeterwave solid -state oscillators is demonstrated. The resonator consists of a Fabry -Perot resonator with a grooved mirror. It has a capability for power com-bining. Experimental results from X -band models of the resonator are presented. Frequency -locking andpower -combining with six Gunn diodes are demon- strated. INTRODUCTION Recently many kinds of oscillators are devel-oped in the millimeter and submillimeter wave re-gion. Solid -state devices have many advantages: small size, low weight, and low -voltage power supplies. As the frequency increases, however, out-put power becomes smaller and the dimensions of conventional waveguide cavities become very small. Young and Stephan demonstrated power- combining in a quasi -optical resonator of two devices[ 1 ]. Popovib et al. proposed and demonstrated power -combining using grid oscillators with FET's at lOGHz[2]. Minkgave a theoretical analysis[3]. We have proposed aFabry -Perot resonator with a grooved mirror

Measuring device having a laser and a ring resonator

Abstract: A measuring device for angular rates making use of the Sagnac-effect comprises a ring resonator (12) and a laser (10). The ring resonator (12) forms a part of the resonator cavity of the laser (10). Thereby no precautions to achieve an optical insulation between laser and ring resonator have to be taken. A semiconductor laser serves as laser. Different embodiments of the ring resonator having mirrors, an integrated optical system and a fiber optical system are described.

Use of a dielectric microwave resonator and sensor circuit for determining the position of a body

Abstract: The use of a microwave resonator is proposed as a sensor in an arrangement for determining the relative position of the sensor relative to a metal or non-metal body. The resonator may be a component of an oscillator and determine the natural frequency thereof. The resonator can also be connected as a filter. For suitable uses, it is possible to provide a plurality of resonators which can be designed and connected in accordance with the geometry of the object to be monitored.

Microwave-pumped high pressure gas discharge laser

Abstract: In order to so improve a microwave-pumped, high-pressure, gas-discharge laser, in particular, excimer laser, with an optical resonator, with a resonator gas volume arranged therein and extending along an optical axis thereof, with a microwave coupling structure enclosing the resonator gas volume within it and with a microwave generator connected to the microwave coupling structure, that a wall breakdown is substantially suppressed, it is proposed that a central area with an electric field intensity lying above a threshold value for a high-pressure gas discharge be disposed within the resonator gas volume in a transverse direction to the optical axis and be adjoined on both sides thereof by outer areas with a field intensity lying below the threshold value for the high-pressure gas discharge

Dielectric resonator having a cutout portion for receiving an unitary tuning element conforming to the cutout shape

Abstract: This dielectric resonator comprises a cylindrical hollow case made of metal, a cylindrical hollow dielectric resonator element which is fixed and held in the case, and a dielectric tuning unit which is inserted into or withdrawn from a hollow portion of the dielectric resonator element. The hollow portion of the dielectric resonator element is formed by at least one, or a plurality of, cutout portions which extend along respective radii of the cylindrical dielectric resonator. In this dielectric resonator, the overall effective dielectric constant as a whole can be varied by inserting the tuning unit into or withdrawing it from the hollow portion of the dielectric resonator element. When the tuning unit is withdrawn from the hollow portion of the dielectric resonator element, part of an electric field path at the dielectric resonator element is interrupted by the cutout portions.

Tubular dielectric waveguides and resonators

Abstract: The effect of the central hole in tubular dielectric waveguides is quantitatively displayed in eigenvalue diagrams for the five lowest modes of propagation. The measurement of the relative dielectric constant for tubular dielectric resonators is described. The tuning mechanism which utilizes a dielectric rod protruding into the tubular TM/sub 01/ resonator is analyzed by the finite integrated method. >

Surface resonator for nuclear magnetic resonance equipment

Abstract: A surface resonator suitable for use in nuclear magnetic resonance equipment has two adjacently disposed windings, the respective ends of each winding being connected to each other through a series circuit including two capacitors. The respective junctions of the capacitors with each other constitute the electrical symmetry point for each winding, and are connected to ground. The signal tap for the surface resonator is galvanically taken at the ends of each winding. The surface resonator can be used for imaging and spectroscopy using nuclear magnetic resonance principles.

Rod type dielectric resonating device with coupling plates

Abstract: A dielectric resonating device comprises a conductive case, a bar-shaped dielectric resonator body located in the case, exciting means for exciting the dielectric resonator body, and at least one plate located between the case and the dielectric resonator body, forming at least two resonators of said device. An inner peripheral end of the plate is fixed to the dielectric resonator body. An outer peripheral end of the plate is located to face the case and define therewith a gap for coupling adjustment between the two resonators. The exciting means has electrodes connected to both ends of the dielectric resonator body, and input and output connectors fixed to the electrodes. The electrodes each have the shape of a flat plate and they are located with a gap between them and the case.

Open resonator for electromagnetic waves having a polarized coupling region

Abstract: An open resonator comprises two concave spherical reflectors or one spherical and one plane reflectors positioned so as to form a resonant structure and each being provided at an electromagnetic coupling region thereof with a large number of conductor stripes disposed in parallel at a spacing sufficiently small in comparison with the wavelength of an incident electromagnetic wave. The diameter of the circular coupling region can be made very large in comparison with the wavelength. An ultra-high Q value can be obtained with the open resonator with very high excitation efficiency to a resonator mode. The Q value of the open resonator can be varied with the angle between the directions of the conductor stripes of the two reflecting mirrors.

A 94 GHz low noise GaAs FET oscillator using whispering-gallery dielectric resonator modes and a new push-push configuration reducing 1/f converted noise

Abstract: Results obtained in the design of a 47-94 GHz GaAs MESFET oscillator-doubler using a dielectric resonator are presented. A push-push configuration was used for the generation of the fundamental frequency at 47 GHz in the FET drain at the output. This topology produces noiseless oscillators-doublers. Two versions of this circuit were manufactured: the first used a TE/sub 01 delta /-mode cylindrical dielectric resonator. The resonator dimensions were calculated by computer or a fundamental frequency at 47 GHz. The second used planar whispering-gallery modes. The results obtained from the prototypes are presented. It is felt these devices show promise for low-noise millimeter-wave use. >

Microwave Ceramic Dielectrics and Their Applications

Abstract: Many kinds of dielectric resonator materials have been developed since 1970, and in the present decade, the Q values of these have been remarkably improved. Dielectric resonators with dielectric constant from 20 to 90 are now available, and they are being used for appilications such as microwave filters and oscillators. Along with material development, new techniques and designs have been developed and applied to dielectric filters.

Phase-conjugate resonator

Abstract: By incorporating a phase-conjugating process (Stimulated Brillouin Scatteg) with a master oscillator power amplifier laser cavity, a new phase conjugate resonator (PCR) is obtained. The PCR utilizes flashlamp-pumped dye lasers and a resonator cavity that is formed by a 100% mirror on one end and a Stimulated Brillouin Scattering (SBS) cell on the other end. The SBS cell functions as one of the mirrors of the resonator and causes the entire system to operate as a phase conjugate resonator. The result is vastly improved (an order of magnitude) beam qualities over conventional resonators for large lamp systems.

Solution of the resonant frequencies of a microwave dielectric resonator using boundary element method

Abstract: The methods currently used for computation of resonant frequencies of a microwave dielectric resonator all require knowledge of the field structures, both inside and outside the resonator, and therefore are strictly limited. The authors discuss the general principle of solution of resonant frequencies of the dielectric resonator by the boundary element method. Through discretisation, the boundary integral equations are reduced to a generalised eigenvalue equation, with the eigenvalues as the resonant frequencies. The method presented is, in principle, applicable to an arbitrarily shaped dielectric resonator. Some results are given and compared with previous data published as a demonstration of the validity of the method.