Showing papers on "Dielectric resonator antenna published in 1971"

Dual crystal resonator apparatus

Abstract: Algebraic combination of the frequencies of two or more selected modes of piezoelectric crystal resonator vibrations yields a total frequency signal output which has a substantially zero temperature coefficient of frequency.

Temperature compensated frequency stabilized composite dielectric resonator

Abstract: A composite dielectric resonator having stabilized resonant frequency against the variation of ambient temperature, comprising two kinds of low attenuation dielectric elements each having the temperature coefficient of the dielectric constant in opposite signs. The two dielectric elements are coupled together so that the contact surface is extending substantially parallel to the vector direction of the high frequency electric field. Further improvement of the resonator for obtaining fine adjustment facility is achieved by providing at least an adjustable element, such as a metal post closely arranged to the resonator element for adjusting the electromagnetic energy in the resonator.

Multi-function antenna coupler

Abstract: The antenna coupling circuit facilitates simultaneous reception and transmission of information carrying radio signals through a common antenna A single filter having a plurality of helical resonator sections forms the harmonic filter of the transmitter, the preselector of the receiver, and a duplexer for connecting both the transmitter and receiver to a single antenna A first plurality of the helical resonator sections are connected between the antenna and the input stage of a receiver which passes the band of frequencies to be received while reflecting the frequencies to be transmitted A second plurality of helical resonator sections are connected between the output of a transmitter and the antenna which passes the frequencies to be transmitted while reflecting the frequencies to be received The coupling between individual helical resonators is arranged to discriminate against frequencies higher than the passband All of the cells of the filter circuit are mechanically connected together to form an integral compact structure

Double Dielectric Resonator (Correspondence)

Abstract: Equations are derived from which the resonant frequencies of the double dielectric resonators can be calculated taking into account the influence of the conducting walls of the waveguide or the strip line. A comparison between theoretical and experimental results is also given.

Piezoelectric helmholtz resonator for energy conversion

Abstract: A Helmholtz resonator comprising an orifice and an otherwise enclosed volume includes one or more cascaded hollow piezoelectric cylinders. The resonator effects a conversion between an air flow and electrical energy, one energy form being applied as an input to excite the resonator and the other energy form being directly derivable as an output.

Microwave cavity resonator with printed circuit interior walls and modulation coils

Abstract: A microwave cavity resonator useful in electron paramagnetic resonance spectrometers made from a printed circuit board having an electrically conductive surface printed on one side thereof and folded so as to form a plurality of the walls of a parallelepipedon cavity resonator, the conductive surface of the circuit board forming the inner conductive surfaces of the cavity. Modulation coils formed by printed circuit techniques on the other side of the circuit board serve as field modulation coils for the cavity resonator, the conductive inner wall surfaces aligned with said coils being made pervious to enhance penetration of the modulation field into the cavity resonator.

Quasi-stationary wave patterns inside infinite-strip open resonators.

Abstract: The quasi-stationary wave patterns inside a two-mirror optical resonator are evaluated as the sum of a progressive and a regressive wave by assuming the mirrors to be illuminated by the fundamental mode of the resonator at a resonance frequency. The progressive and the regressive waves are also evaluated in the case of the first-order mode. Calculations are made for an infinite-strip Fabry-Perot resonator, as well as for a cylindrical and a confocal resonator, with Fresnel number N = 1.

Circuit for sustaining oscillation of a resonator by a frequency above the natural frequency of said resonator

Abstract: An electronic circuit allowing sustaining oscillation of a resonator by a reference frequency substantially exceeding the natural frequency of the resonator, wherein pulses at reference frequency and natural frequency are applied to the inputs of an AND-gate and the resonator is coupled to the output of the AND-gate for sustaining its oscillation by the output pulses of the AND-gate.

Antenna design for surface wave suppression

Abstract: Means for suppressing the excitation of electromagnetic surface waves on a dielectric converter antenna. A hole is cut in the dielectric where it covers the antenna. A plug of the dielectric material is coated around its rim with a metal and then fitted into the hole such that the metal coating extends the conducting surface of the antenna through the dielectric material. The metallic coating minimizes the possibility of surface wave excitation by confining the waves reflected by the dielectric-air interface to the chamber formed by the coating.

Compensated folded resonator

Abstract: In a folded optical resonator, in one arm of which a Brewster element is located, the tilted reflector and the Brewster element both introduce astigmatism into the system, which gives rise to resonator instability. The astigmatic effects can be made to counteract each other to a large extent with resonator stability thereby assured if the several parameters of the system are properly related to each other according to an equation for stability.

Some Considerations About the Diffraction Loss of Open Resonators (Correspondence)

Abstract: The concept of "effective" number of Fresnel zones is used in order to discuss some properties of the losses of the open resonators, as functions of the resonator geometry. The cases of the flat-roof resonator and the step-rim resonator are discussed in detail.

Encapsulant for buried u.h.f. antennas

Abstract: Certain applications for above-ground communications require antennas placed below the ground surface. Under these conditions, reasonable antenna performance can be achieved if the antenna is encapsulated in a uniform low-loss dielectric having a relative permittivity near that of the surrounding earth. It is shown that, with special conditioning, refractory concrete is a suitable encapsulant. It is castable, extremely durable and has a relative permittivity of 6.5-7.0 and a loss tangent of 0.005-0.006 at 400 MHz. Resonator measurements have shown that the desired electrical properties can only be achieved, however, if the material is dried at a temperature of 125-150°C. Once dry, the concrete surface must be sealed to prevent water absorption.

Ammonia beam masers employing parallel plate and conical types of open resonator

Abstract: The operation of an ammonia beam maser with plane parallel and conical types of open resonator is described Oscillation has been achieved with both types of resonator The complex lineshapes of emission are correlated qualitatively with resonator microwave field distribution and molecular beam divergence

Piezoelectric ceramic resonator with asymmetrically rough edge

Abstract: A PIEZOELECTRIC CERAMIC RESONATOR WHICH IS FREE FROM SPURIOUS VIBRATIONS WHEN OPERATING IN A HIGH FREQUENCY RANGE. THE RESONATOR IS COMPOSED OF A THIN PIEZOELECTRIC CERAMIC PLATE HAVING AN ELECTROMECHANICAL COUPLING FACTOR FOR THE THICKNESS-EXTENSIONAL MODE VIBRATION AT LEAST FOUR TIMES HIGHER THAN THE MECHANICAL COUPLING FACTOR FOR THE CONTOUR MODE. THE THIN CERAMIC PLATE HAS A THICKNESS FOR CAUSING IT TO VIBRATE AT A PRESELECTED FREQUENCY THE THICKNESS-EXTENSIONAL VIBRATION MODE AT A FREQUENCY RANGE HIGHER THAN TWENTY MEGACYCLES AND HAS AN ASYMMETRICALLY ROUGH PERIPHERAL EDGE HAVING A ROUGHNESS ON THE ORDER OF ONE QUARTER WAVELENGTH OF THE PRESELECTED FREQUENCY FOR ELIMINATING UNWANTED VIBRATIONS. ELECTRODES ARE PROVIDED ON SAID CERAMIC PLATE FOR CAUSING SAID VIBRATION WHEN AN ALTERNATING CURRENT IS SUPPLIED THERETO. D R A W I N G

Acoustically active resonator

Abstract: An acoustically active resonator is provided having relatively large surface area parts in order to efficiently couple the movement of the oscillating parts to the surrounding atmosphere. In most of the disclosed embodiments, the oscillating parts are disposed about the periphery of the resonator in order to maximize the surface area producing the air compression and rarefaction. A web interconnects the midpoint of the oscillating elements to transmit motion of the web into predictable motion of the oscillating elements. Means are also provided for moving the web at the resonant frequency of the resonator.

Two Innovations for Improving Harbor Resonators

Abstract: The results of an experimental study on two aspects of resonator behavior for harbor entrances are presented. The first aspect involves a battery of three resonators tuned to cover a wide frequency band. It is found that the efficacy of the battery is improved by increasing the distance along the main entrance channel between the individual resonators. An approximate method is presented for estimating the frequency of the most resonant peaks in the response of a battery to a flat incident wave spectrum. The method is a based on previous results. The second aspect investigated is that of nonuniform depths in the resonator configuration. If the still water depth in the resonator is reduced, the length of the resonator for resonance is considerably reduced. This will allow savings in capital expenditure on breakwaters incorporating rectangular resonators, and on excavating the resonators. However, the efficiency of the resonator is also impaired.

A Laser Resonator with a Selector for a Higher Transverse Mode (Correspondence)

Abstract: A new laser resonator is proposed in which a specified higher order Hermite-Gaussian mode becomes the lowest loss mode. The two reflectors in the resonator are blocked in the vicinity of the characteristic zeros of the mode and the edge (i.e., |x|, |y| /spl rlarr2/ /spl infin/). In such a configuration the mode volume is enhanced, and mode selection is improved as compared with a conventional resonator in which a Gaussian mode is the dominant one. We have specialized to TEM/sub 22/ mode. The solutions to the integral equation for the eigenmodes and eigenvalues of the resonator are obtained on a digital computer. The computed eigenfunctions and mode selection show several interesting characteristics, and the loss mechanism for a few low-loss modes are elucidated. The computational results show that the location and the width of the blocking structure are closely related to the mode competition phenomenon and therefore mode selection.