Decay Method for Measuring Complex Dielectric Constants During Microwave Processing

1994 ◽  
Vol 347 ◽  
Author(s):  
O. Iny ◽  
M. Barmatz
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Modulation Frequency ◽  
Resonant Mode ◽  
Dielectric Constants ◽  
Sample Temperature ◽  
Cavity Modes ◽  
Sample Support ◽  
Quality Factor Q

ABSTRACTWe have developed a fast in-situ method for measuring the quality factor, Q, and resonant frequency, fr, for an isolated microwave resonant mode. The mode resonant frequency was continuously monitored using a phase modulation frequency tracking technique. The quality factor was determined by periodically switching off the microwave power and fitting the decay curve to an exponential. The cavity perturbation method was used with small spherical samples (ka « 1). Combining the Q and fr data with a non-contact measurement of the sample temperature permits the calculation of the temperature dependence of the real (ε′) and imaginary (ε″) dielectric constants. Because of the speed of this technique (≈1 μSce), it can be used during processing to continuously measure the dielectric constants of the material without perturbing the sample temperature. Measurements were performed using isolated TM010 and TEI11 cylindrical cavity modes. Care was taken to minimize the perturbing effects of the sample support. The accuracy of the frequency tracker was verified at room temperature from measurements on several alumina spherical samples. The decay technique was also verified from measurements on several small spherical nylon samples.

Effect of BaCu(B2O5) on the sintering temperature and microwave dielectric properties of Ba(Nd0.8Bi0.2)2Ti4O12 ceramics

2010 ◽  
Vol 25 (12) ◽  
pp. 2380-2383 ◽  
Author(s):  
Yi Zeng ◽  
Hong Wang ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Resonant Frequency ◽  
Temperature Coefficient ◽  
Quality Factor ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Potential Candidate ◽  
Microwave Dielectric ◽  
Quality Factor Q

The effect of BaCu(B2O5) (BCB) on the sintering temperature and microwave dielectric properties of Ba(Nd0.8Bi0.2)2Ti4O12 (BNBT) ceramics was investigated. The sintering temperature of the BNBT ceramics was significantly reduced from 1300 to 900 °C. Due to adding BCB into Ba(Nd1–xBix)2Ti4O12, the temperature coefficient of resonant frequency can be adjusted to zero with BCB content increasing. Good microwave dielectric properties of quality factor (Q×f) = 2600 GHz, εr = 75, and τf = 5 ppm/°C were obtained for BNBT with 7 wt% BCB sintered at 925 °C for 2 h, which make it a potential candidate for low temperature cofired ceramics applications.

Vibrational and thermoelastic behavior of punched-beam micro resonators containing odd-number of slots

2017 ◽  
Vol 232 (16) ◽  
pp. 2821-2829 ◽  
Author(s):  
Saeid Asadi ◽  
Mahdi Moghimi Zand ◽  
Tahereh Fanaei Sheikholeslami
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Resonant Frequency ◽  
Quality Factor ◽  
Three Dimensional ◽  
Resonant Mode ◽  
Comsol Multiphysics ◽  
Beam Length ◽  
Microelectromechanical System ◽  
Three Dimensional Simulations

Thermoelastic quality factor is an important mechanism for determining quality factor of a microelectromechanical system resonator, which works in near vacuum, and the resonant frequency is an important characteristic of a resonator. This paper studies variations of the thermoelastic quality factor and the resonant frequency of three- and five-slotted clamped-clamped beam microelectromechanical system resonators. The study has been done by using three-dimensional simulations based on finite element method by COMSOL Multiphysics. Resonant frequency is a function of stiffness and mass of the beam, therefore punching slots in the beam changes the resonant frequency. In addition, slots usually decrease the amount of coupling between mechanical resonant mode and thermal modes, thus improve the thermoelastic quality factor. The C–C beam lengths are considered to be 30.5 µm, 100 µm, and 400 µm. The results show the resonant frequency and corresponding thermoelastic quality factor of the three-slotted beams are greater than five-slotted beams, and a maximum resonant frequency of the three-slotted beams is achieved when the length of inner slot is about 32%–36% of the beam length.

Theoretical and practical aspects of absorption in the application of in‐seam seismic coal exploration

Geophysics ◽  
1982 ◽  
Vol 47 (12) ◽  
pp. 1645-1656 ◽  
Author(s):  
Th. Krey ◽  
H. Arnetzl ◽  
M. Knecht
Keyword(s):  
Quality Factor ◽  
Seismic Waves ◽  
Guided Waves ◽  
Country Rock ◽  
Low Frequency ◽  
Quality Factors ◽  
Ruhr Area ◽  
Phase Signal ◽  
Quality Factor Q

During the last two decades, the detection of coal seam discontinuities by seismic waves guided by the seam has become a special branch of exploration seismics in Europe. Waves consisting purely of SH motion (so‐called waves of Love type) are of special interest, and the rather high frequencies of the Airy phase, in thin seams, are most important because they present very high reflectivity at seam interruptions. Absorption increases with frequency in most layers, and therefore attenuates the high Airy‐phase frequencies more severely than the earlier low‐frequency part of the guided waves. Another fact additionally impairs the Airy‐phase signal: the quality factor Q is much lower in coal than in the schists and sandstones of the Carboniferous country rock. Unfortunately, most of the energy of the Airy phase is transferred by the coal, whereas the lower frequencies have their main energy conveyed by the country rock above and below the seam. In order to allow a better understanding of the influence of absorption on Love‐type seam waves, several simplified computations were carried out for the fundamental mode of a seam typical for the northwest‐German Ruhr area. The assumptions are as follows: The quality factors [Formula: see text] for coal and [Formula: see text] for the country rock do not depend upon frequency; higher powers of [Formula: see text] and [Formula: see text] can be neglected; and the distance from the source is large enough to allow the two‐dimensional plane‐wave case to be considered. The mathematics resulting from these assumptions and adequate data processing of transmission records provides the possibility to determine the quality factor [Formula: see text] of coal in‐situ, although the thickness of the seam may be much smaller than the wavelengths involved. [Formula: see text] may become of interest for practical mining problems.

scholarly journals Liquid Mass Sensing Using Resonating Microplates under Harsh Drop and Spray Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Said Mahajne ◽  
Dafne Guetta ◽  
Stella Lulinsky ◽  
Slava Krylov ◽  
Yoav Linzon
Keyword(s):  
Resonant Frequency ◽  
Resonant Mode ◽  
Ambient Conditions ◽  
Mass Sensing ◽  
Operation Conditions ◽  
Multiple Cycles ◽  
Volatile Liquids ◽  
Deposited Film ◽  
Harsh Conditions

We have performed in situ real time mass sensing of deposited liquid volatile droplets and sprays using plate-like microstructures, with robust and reusable performance attained over harsh conditions and multiple cycles of operation. A home-built electrooptical sensing system in ambient conditions has been used. The bimorph effect on the resonant frequency of altered mass loading, elasticity, and strain had been carefully compared, and the latter were found to be negligible in the presence of nonviscous liquids deposited on top of our microplate devices. In resonant mode, the loaded mass has been estimated from measured resonant frequency shifts and interpreted from a simple, uniformly deposited film model. A minimum submicrogram detectable mass was estimated, suggesting the system’s potential for robust, fast, and reusable sensing capabilities, in the presence of volatile liquids under harsh operation conditions.

NÉEL LINES STRUCTURES IN UNIAXIAL FERROMAGNETS WITH QUALITY FACTOR Q > 1

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1947-C8-1948
Author(s):  
J. Miltat ◽  
P. Trouilloud
Keyword(s):  
Quality Factor ◽  
Quality Factor Q

scholarly journals 422 Million intrinsic quality factor planar integrated all-waveguide resonator with sub-MHz linewidth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Matthew W. Puckett ◽  
Kaikai Liu ◽  
Nitesh Chauhan ◽  
Qiancheng Zhao ◽  
Naijun Jin ◽  
...  
Keyword(s):  
Quality Factor ◽  
High Capacity ◽  
Precision Spectroscopy ◽  
Narrow Linewidth ◽  
Waveguide Resonator ◽  
Environmental Disturbances ◽  
Fiber Communications ◽  
Intrinsic Quality ◽  
Quality Factor Q ◽  
Quantum Photonics

AbstractHigh quality-factor (Q) optical resonators are a key component for ultra-narrow linewidth lasers, frequency stabilization, precision spectroscopy and quantum applications. Integration in a photonic waveguide platform is key to reducing cost, size, power and sensitivity to environmental disturbances. However, to date, the Q of all-waveguide resonators has been relegated to below 260 Million. Here, we report a Si3N4 resonator with 422 Million intrinsic and 3.4 Billion absorption-limited Qs. The resonator has 453 kHz intrinsic, 906 kHz loaded, and 57 kHz absorption-limited linewidths and the corresponding 0.060 dB m−1 loss is the lowest reported to date for waveguides with deposited oxide upper cladding. These results are achieved through a careful reduction of scattering and absorption losses that we simulate, quantify and correlate to measurements. This advancement in waveguide resonator technology paves the way to all-waveguide Billion Q cavities for applications including nonlinear optics, atomic clocks, quantum photonics and high-capacity fiber communications.

Study of Inductance-Coupling-RFID Tag's Quality Factor

2013 ◽  
Vol 722 ◽  
pp. 198-201
Author(s):  
Cai Feng Liu ◽  
Fu Gui Yan ◽  
Di Feng Lu ◽  
Yang Mei
Keyword(s):  
Quality Factor ◽  
Simulation Analysis ◽  
Influence Factors ◽  
Rfid Tags ◽  
Space Thickness ◽  
Manufacturing Quality ◽  
Length Width ◽  
Quality Factor Q

To improve the read performance of RFID tags,improve the quality factor is very important. Firstly,from theory and practical, confirmed that quality factor Q is very important for RFID tags,a higher Q means the tag could have a good performance. Then,through calculations and simulation,analysis the influence factors of Q. With simulation figures show that length, width, space, thickness of the tags coil all affect the Q,but when manufacturing of tags , the control of manufacturing quality and accuracy is very difficultly. Finally, shows many figures about tags manufacturing quality and accuracy of manufacturing which have lower Q and badly read performance.

scholarly journals In-Situ Thin Film Growth of PbTiO3 By Multi Target Sputtering

1994 ◽  
Vol 341 ◽  
Author(s):  
Thomas Maeder ◽  
Paul Muralt
Keyword(s):  
Lead Oxide ◽  
Film Growth ◽  
Sputter Deposition ◽  
Dielectric Constants ◽  
Thin Film Growth ◽  
Film Morphology ◽  
Reactive Sputter Deposition ◽  
Pt Electrodes ◽  
Oxide Flux

AbstractThe in-situ reactive sputter deposition of PbTiO3 on Pt/Ti/SiO2/Si from two metallic targets was investigated. A minimal lead oxide flux of two to three times the titanium oxide flux is needed in order to obtain stoichiometric films with the perovskite structure. For higher fluxes, the Pb/Ti ratio in the film stays at the stoichiometric value 1; the orientation changes from random to <100>; and the film morphology transforms from a rough to a smooth polycrystalline film. The obtained dielectric constants vary between 40 and 150, the losses between 2 and 4 % (10 kHz). The method could be extended to PbZrxTi1-xO3 for x ≤0.7. The orientation is lost when the Pt electrodes are replaced by RuO2 electrodes.

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