Coaxial Resonator Research Articles

Coaxial Vibratory Gyroscope Using Two Pairs of Degenerate Modes

A gyroscope using two pairs of degenerate modes for wide-range sensing is proposed. We focused on a coaxial resonator composed of a cylinder and a column. To evaluate the characteristics of the proposed gyroscope, we analyzed its frequency response and rotational response both experimentally and numerically. From the frequency response under rotation, there was a difference between the shifts of resonance frequencies of two detecting modes. We also found that the lower-frequency mode had higher sensitivity and the higher-frequency mode had a wider linear region from the rotation response of each mode. These results suggest that high sensitivity for low-speed rotation and a wide linear region for high-speed sensing can be attained simultaneously by a single resonator with the help of two different pairs of degenerate modes.

Duplexer designed on the basis of microstrip filters using high dielectric constant substrates

A microstrip duplexer for a modification of a PCS communication system operating at frequencies of 1.84–1.87 and 1.75–1.78 GHz is described. The duplexer containing microstrip bandpass filters on high dielectric constant substrates (ɛr = 92) are compared with duplexers manufactured on microwave ceramic materials with high values of ɛr. The microstrip bandpass filters use stepped-impedance resonators placed one near another with a gap of 0.1–0.2 mm. It is shown that the microstrip duplexer has slightly lower insertion loss and occupies smaller volume than a duplexer using coaxial dielectric resonators having a rectangular cross section of 3 × 3 mm and ɛr = 92.

Novel Coupling Structure for the Resonant Coaxial Probe

Herein we present a technique for performing complex permittivity measurements with an overmoded, evanescently perturbed coaxial resonator at microwave frequencies. The design of a noninvasive electromagnetic coupling structure, which allows transmission measurements to be taken from one end of a resonant section of coaxial cable, is discussed in detail. Quasi-spectral information was obtained through the exploitation of higher order resonances, and complex permittivity measurements of a number of common industrial solvents were taken at multiple discrete frequencies between 1 and 8 GHz. A combination of experimental and simulated results was used also to characterise the device behavior. The high stability of temporal measurements, coupled with the robustness of the design, make this device ideal for analytical chemistry and industrial process control.

Microfluidic device for compositional analysis of solvent systems at microwave frequencies

A device for analysing the chemical composition of single- and multi-phase solvent flows using microfluidic dielectric spectroscopy is demonstrated in this work. An open-circuited, half-wavelength, coaxial resonator operating at microwave frequencies (i.e. harmonics of 600MHz) was embedded in a compression-sealed polytetrafluoroethylene microfluidic chip for in situ characterization of solvent–solvent and solute–solvent mixtures of varying concentration, and an aqueous–organic segmented flow. Results are shown for a solvent mixture of acetonitrile in toluene as a test system, exhibiting a sensitivity limit of 400nM. In addition to being highly sensitive, the measurement system is fast, robust and non-invasive, and can be readily miniaturized.

Analysis of an optical resonator formed by a pair of specially shaped axicons

We propose a design for an optical resonator suited to using large-bore active media. The resonator consists of a pair of waxicons, so we call it a "wwaxicon optical resonator." The resonator is considered a conventional (solid) resonator surrounded by coaxial annular resonators. A numerical simulation of the resonator designed for use in a commercial CO2 laser is performed. It is found that parasitic oscillation modes can be suppressed by the use of an spatial-frequency filter. The resonator exhibits oscillation in the TEM*01 transverse mode and produces twice as much output power as a sevenfold multipass stable optical resonator.

Tunable phaselike resonance in split coaxial gold nanotube resonator pair

We propose the split coaxial nanotube resonator pair and investigate its plasmon resonance properties theoretically. It is found that the resonance peak splits and forms more dips with the increase of the number of slits in the structure. We present that the splitting behaviors result from the phaselike resonance of adjacent tubes. In addition, it shows the optical transmission peaks can shift and attenuate by tuning the split width, the thickness and dielectric constant of the medium layer between two coaxial nanotubes. The instantaneous electric field distributions show that symmetry and antisymmetry quadrupole modes exist in these structures.

A novel coaxial loop resonator for wireless power transfer

We present a novel resonator, based on a coaxial cable structure, suitable for wireless power transfer (WPT) applications. Its advantages are compactness, ease of manufacture, and low cost. WPT resonators generally operate in the HF, LF bands, using magnetic field coupling and a lumped capacitance for achieving the sought resonance. In our structure, the electric field is primarily confined inside the coaxial cable, whereas the magnetic field is generated by the currents flowing on the external conductors. The article describes the resonator structure, illustrates its design procedure, and discusses quality factor contributions. A few resonators with Q higher than 900, operating around 30 MHz, have been built, simulated, and measured confirming the validity of the proposed approach. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2012.

Miniaturized coaxial cavity resonator based on anisotropic negative permeability metamaterial loading

AbstractIn this letter, a miniaturized coaxial cylindrical cavity resonator was presented, in which a combination of an ordinary dielectric material and a metamaterial layer has been inserted. First, the general dispersion relation was formulated for such a resonator in three different cases in which the metamaterial layer is: (i) an isotropic μ and ε negative (double negative or DNG) medium; (ii) an isotropic μ negative (MNG) medium; or (iii) an anisotropic MNG (AMNG) medium. Extracting the approximate dispersion relation in the subwavelength scenario, it is shown that this configuration may in principal exhibit an arbitrary low resonant frequency for a fixed dimension, not only in the case of isotropic DNG or isotropic MNG layers but also in the case of a much less complex AMNG layer, which is of importance from the practical realization point of view. In comparison with miniaturized rectangular cavities and also miniaturized one‐dimensional resonators, the aforementioned resonator provides the possibility of selecting a distinct mode and also provides a further degree of freedom in the approximate dispersion relation, which brings more flexibility in designing miniaturized resonators. As an example, design and simulation of a miniaturized coaxial cavity resonator together with the complete design of the AMNG layer are presented. The resultant cavity diameter is shortened by ∼ 60% in comparison with theoretical minimum dimensions of a cylindrical cavity resonator of the same height. Finally, the designed cavity has been fabricated and tested. The measured and simulated responses are in close agreement with each other. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:595–599, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26600

On-line fingerprinting of fluids using coaxial stub resonator technology

Here we demonstrate the proof-of-principle of a coaxial stub resonator to assess the dielectric properties of fluids. This radio-frequency spectroscopy method is based on coaxial stub technology and comprises quarter wave length open-ended resonators that are filled with a liquid sample as dielectric between inner and outer conductor. Changes in the dielectric properties of the liquid sample result in changes in the electric properties of the resonator, e.g., its resonance frequency and quality factor. In addition to a batch resonator, results obtained with a flow-through resonator indicate that the concept can be further developed into a cost-efficient and low-maintenance sensor for the on-line fingerprinting of the dielectric properties of fluids, such as drinking or waste water, ethanol and glycerol.

Extensive Modeling of a Coaxial Stub Resonator for Online Fingerprinting of Fluids

A straightforward method of extensive modeling of a lossy stub resonator system for online fingerprinting of fluids is presented in this paper. The proposed model solves the telegrapher's equations including the skin effect and dielectric losses and describes the amplitude versus frequency response of lossy coaxial stub resonators with a fluid under investigation as dielectric. The adequacy of the method is demonstrated by comparing simulations with experimentally obtained data. Even though we applied the model to a coaxial stub resonator for the online fingerprinting of fluids (e.g., for water quality monitoring), the potential applicability of the method reaches further. Indeed, the method introduced here may be useful for different types of sensors based on lossy transmission line theory

Miniature coaxial resonator and related bandpass filter with ultra-wide stopband

Resonator of a new type is described, which is formed by two coaxial conductors applied onto the internal and external surfaces of a ceramic tube arranged in a metal case. An equation for the resonant frequencies is derived. In comparison to a standard coaxial quarter-wave resonator, the proposed device has a shorter length and manifold increased ratio of frequencies of the second resonance to the first resonance. The new resonator can be used for the creation of bandpass filters with ultra-wide stopband. The frequency response of a working prototype four-resonator filter is presented, in which the stopband at a −90 dB level extends up to a frequency that is 47 times greater than the central frequency of the passband.

Compact CPW-Fed Combline Filter in Substrate Integrated Waveguide Technology

In this letter, the design and experimental results of compact low loss combline filters, based on the extension of the classical coaxial waveguide resonator to Substrate Integrated Waveguide (SIW) technology, are succesfully demonstrated. A three-pole 5% FBW Chebyshev filter has been designed, fabricated and measured. The fabricated device shows an excellent agreement with simulated results. These structures keep the low-cost fabrication scheme of single-layer PCB processing, while requiring less than half the area compared to a conventional SIW design.

A 2.45 GHZ REENTARNT COAXIAL CAVITY FOR LIGUID STERILIZATION BASED ON NON-THERMAL MICROWAVE EFFECT

According to the intracellular electromanipulation model, bacteria can be killed at as high as 10 6 V/m electrical flelds on microwave band. We designed and constructed a modifled microwave coaxial cavity resonator for liquid sterilization. The cavity could concentrate the fleld on a very small area, and the liquid can pass it in milliseconds. The bacteria can be killed by the very high fleld, but with a slight temperature increase. The designed resonator is simulated and analyzed by electromagnetic simulation code. The results indicated that when the input power reached 100W, the electric fleld on the area of liquid can reach 10 6 V/m. Preliminary experimental results indicated that when the input power was 100W, the bactericidal rate was > 90%, and the temperature of the liquid only increased 8.6 - C.TM P b

双耦合同轴腔TM310模加载空波导输出回路

双耦合同轴腔TM310模加载空波导输出回路

Neuroradiology investigations before scanning

Coaxial tomography (CT) and magnetic resonance imaging (MRI) scans are so much part of neurological investigation these days and provide such detailed information that even thorough neurological clinical examination may be neglected. The investigations in common use forty years ago were pneumoencephalography, ventriculography in babies with hydrocephalus, and carotid angiography with the injection of X-ray contrast to outline the arteries.

RF system of HIRFL-CSRe

The operational frequency range of RF system at HIRFL-CSRe (cooling storage experimental ring) is 0.5–2 MHz, and it works in fundamental and second harmonic. It includes five sections: ferrite ring loaded RF cavity, RF generator, low-level system, computer system and cavity cooling. The cavity is based on the coaxial resonator type which is short at the terminal with one gap and loaded with domestic ferrite rings. The RF generator is designed in a push-pull mode. The low-level control system is based on PID, DSP, FPGA and DDS9854+USB interface and has three feedback loops. This RF system is designed independently and manufactured domestically. For the first time, it realized the pulse modulation, variable harmonic and CW operational modes. The maximum output power is up to 70 kW and the 10 kV RF voltage is used to capture the irradiative beam and decelerate the beam from 400 to 30 MeV/u.

Mode Excitation in the Coaxial Probe Coupled Three-Layer Hemispherical Dielectric Resonator Antenna

In this paper, a coax-probe excited multilayer dielectric resonator antenna (DRA) structure is rigorously analyzed from the modal perspective. The full-wave Green's function approach is presented for the analysis of such multilayer structures with an arbitrary number of layers with greatly reduced computational overhead. Additional reduction in computation time is demonstrated for a centered probe. Also, the modes of the multilayer DRA can be identified from the analysis, which can be used to explain the broadband nature of the coupling. The layer permittivities are optimized for broadband operation of the coax-fed DRA. The bandwidth enhancement for a centered and offset probe is seen to be due to a combination of several DRA modes and the probe resonance. Frequency tuning of the antenna structure is also demonstrated by exciting the antenna at a higher order mode, maintaining the broadband characteristics. The radiation characteristics of the antenna are also investigated.

Measurement of Permittivity of Ferroelectrics Using Coaxial Resonator

This paper presents a coaxial resonator technique applied for the measurement of the permittivity of ferroelectric thick film. A 1/4-wavelength coaxial resonator with appropriate dimensions were designed and made for measurements so that there is only TEM fundamental resonance in the interest frequency range. The permittivity may be extracted from the measured TEM fundamental resonant frequency in the resonator. The equivalent capacitance to the part between sample and open end of coaxial line is discussed, in which the boundary element numerical method was used for modeling the capacitance. The resonant frequency was measured using network analyzer and good experimental results were obtained.

Orthogonal Coaxial Cavity Filters With Distributed Cross-Coupling

In this letter, six-pole filters are presented, in which the coaxial cavity resonators are arranged with 90 degree rotated spatial orientation. Cross-coupling between nonadjacent resonators will appear. In the new proposed filter topologies the cross-coupling elements are not arranged in separated triplet or quadruplet blocks. They interlace to form distributed cross-coupling. Synthesis of the distributed coupling matrix based on the symmetric canonical prototype is discussed. Two different bandpass filter topologies are presented. The first one has an inline arrangement of six orthogonal coaxial cavity resonators. Its distributed cross-coupling consists of four interlaced triplets, which generate two transmission zeros above the passband. The second filter design has a folded arrangement of two inline triplets with strong cross-coupling. An additional interlaced quadruplet pushes the resulting transmission zeros to the complex frequency domain. Measurement results of two corresponding filter prototypes confirm the predicted performance.

Practical design of a high power L‐band linear phase filter for radar applications

AbstractThe design procedure of a linear phase filter suited for radar applications in L‐band is presented.It can manage more than 1 KW of peak power, although it is built in a compact case by using coaxial resonators instead of usual rectangular ones. The design is performed by using the adaptive method invented by the authors. The filter was built and measured, showing good agreement between simulations and experiments. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2717–2721, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26442