Showing papers on "Dielectric resonator antenna published in 1973"

Ultrasonic generator and atomizer apparatus and method

Abstract: A flexural resonator having predetermined resonant modes is mounted by means of a dynamic clamp which prevents movement of the resonator at the line of clamping. An electrically energized driver urges a member against the resonator exciting the predetermined resonant modes therein. The resonator may be utilized to transmit ultrasonic signals operating, for example, as a predator repellant, or as an atomizer of fluids introduced thereupon. Atomization occurs due to driver displacement amplification in the resonator at the point where fluid is directed onto the resonator surface, whereupon the fluid is thrown off of the resonator surface in small droplet form. Atomized droplet size is a function of the resonator amplitude and frequency.

A TE01n Cavity Resonator Method to Determine the Complex Permittivity of Low Loss Liquids at Millimeter Wavelengths

Abstract: Two oversized TE01n cavity resonator systems have been constructed that are suitable for measuring the complex permittivity e=e′ (1 − j tanδ) of low loss liquids at millimeter wavelengths. One of them operates at frequencies from 26 to 70 GHz, while the second, which is described in detail, was tested at frequencies around 136 GHz where a quality factor of about 60 000 was obtained. e′ is determined from the wavelengths measured in the filled and unfilled resonator. The loss factor tanδ is obtained from the half‐widths of the resonance curves in both resonator states. For that purpose, the frequency of the oscillator is swept, and the resonance curves vs frequency are displayed on an oscilloscope. Frequency calibration marks are generated by the absorption resonances of a second long open resonator operating in the HE11m dipole mode which is guided by a thin dielectric thread. To restrict the influence of traces of water in the liquids to be measured, the resonator is permanently connected to an apparatus...

Temperature-stable dielectric resonator filters for stripline

Abstract: There is disclosed a band-reject dielectric resonator filter for stripline, the resonators being disposed over the principal conductor and separated therefrom by a dielectric spacer and offset from the symmetry position over the stripline conductor. The offset is selected so that the magnetic field lines of the stripline pass through the planar, parallel surfaces of the resonator to a maximum degree. Large scale fabrication of the stripline is facilitated, while accurate normal positioning of the resonator is assured; and resonator to stripline coupling is relatively insensitive to small variations in the lateral position. Further, the principal conductor has no substantial degradation of the resonator Q. Strong coupling has been demonstrated with the use of low dielectric constant materials that are readily-temperature compensated. Also, disclosed are a plurality of such resonators coupled together to create specially-shaped reject bands or pass bands.

Velocity modulation microwave tube employing a harmonic prebuncher for improved efficiency

Abstract: The velocity modulation microwave tube includes an electron gun for projecting a stream of electrons over an elongated beam path to a collector structure. An input circuit and an output circuit are disposed at the upstream and downstream ends, respectively, of the beam for applying microwave energy to be amplified to the tube and for extracting the amplified microwave energy from the beam. A penultimate resonator circuit, tuned for a mode of resonance at a frequency near the passband of the tube, is provided just upstream of the output circuit for bunching the current density of the beam passing into the output circuit. A harmonic floating resonator structure is disclosed along the beam path intermediate the input circuit and the penultimate resonator. The harmonic resonator is tuned for a mode of resonance approximately at a frequency corresponding to a harmonic higher than the first of the center frequency of the passband of the tube. The harmonic resonator serves as a prebuncher to bunching the electrons of the beam prior to their entering the final stage of bunching performed by the penultimate floating resonator. The combined action of the harmonic prebuncher resonator and the penultimate final buncher resonator is to substantially increase the radio frequency conversion efficiency of the tube.

Temperature stabilized resonator

Abstract: A hollow compensation member is secured in a wall of the cavity resonator in such a manner as to project inwardly, said compensation member having a wall thickness in the cavity which is less than that of the cavity resonator structure and being made of a material having a lower coefficient of linear thermal expansion than the material forming the structure of the cavity resonator.

Radiation Loss from Open-Circuited Dielectric Resonators (Short Papers)

Abstract: The Q factor of an open-circuited resonator is influenced by dielectric, conductor, and radiation losses. This short paper discusses these losses and shows that insight into the radiation loss can be obtained by an extension to the analysis given by Lewirt. This shows that the radiation loss is a maximum for the dominant mode and that provided the permittivity is not less than 9.0 the radiation losses are at a minimum for the second mode. It is suggested that these results may be applied to the design of filters based on dielectric resonators. The application of the results to stripline resonators in which the dielectric extends past the termination of the upper conducting strip is more difficult, and it is suggested that experimental work is required to investigate postulated improvements. Finally, some of the radiation patterns of the open-circuited dielectric resonators, obtained in this paper, show interesting directional properties which may be applied to the design of antenna systems.

The Design, Analysis, and Performance of Resonant and Nonresonant Microwave Transmission Devices with Theoretically Infinite Rejection

Abstract: There have been several designs proposed for bimodal transmission resonators for use in EPR, Hall effect, and Faraday rotation measurements. Some of these are based on attempts to spatially define the field patterns of the normal modes of cylindrically symmetric resonators. Others try to separate the modes so that in some parts of the resonator, the radio frequency fields of predominantly one mode will be found. In this way, independent adjustment of the mode characteristics is attempted so that an adjustable null transmission resonator results. The property to be measured for a sample placed inside the resonator causes an imbalance and the resulting output appears in place of the null. This paper describes a different approach to the practical realization of such a resonator and gives the appropriate theory for its operation. In the resonator to be described the spatial position of the normal modes can be altered by a simple rotation control, and the input radio frequency field polarization direction can...

Laser with a waveguide-type traveling-wave ring resonator

Abstract: Laser emission was obtained from rhodamine 6G in a traveling-wave ring resonator. The excitation was provided by the second-harmonic of Nd laser radiation. The ring resonator was in the form of a thin gelatin film on a glass rod. The concentration of rhodamine 6G in this film was 10–3–10–2 mole/liter.

Microwave Four-Mirror Ring Resonator (Short Papers)

Abstract: Experiments on an X-band four-mirror ring resonator are described. Measured frequency spacing and quality factor values are given. Clockwise and counterclockwise circulating modes are excited with different amplitudes. Fundamental mode patterns are shown across the circulating beam and across a mirror. They indicate that such modes are similar to those of a two-mirror Fabry-Perot (FP) resonator.

Method and apparatus for tuning coaxial-line section resonators

Abstract: In a coaxial-line section resonator having a short-circuited end, a short-circuited coupling loop is interposed in the space between the coaxial conductors and is mounted on a wall of the resonator for rotation from outside the resonator, whereby the resonant frequency of said resonator is adjusted in response to rotation of the loop.

Band-pass filter and method of making same

Abstract: A band-pass filter comprises a resonator system having a first and a second resonator coupled together by a coupling mass resiliently suspended on supporting means, the first resonator being associated with an electrodynamic transducer capable of converting an input signal into oscillation energy, and the second resonator being associated with an electrodynamic transducer capable of generating an output signal corresponding to the oscillating condition of said second resonator.

Response curve shaping of coupled dielectric resonators

Abstract: Using parallel coupled strontium titanate resonators, we have produced a small 9-GHz bandpass filter, having a lower skirt steepness of 27 MHz per 30 dB of attenuation. Approximate simplified design equations for two relative dielectric constants are also presented.