Frequency-Dependent Quality Factor Modeling of High Resistivity SOI RF CMOS Inductor

2017 ◽  
Vol 54 (9) ◽  
pp. 31-37
Author(s):  
Changjo Lee ◽  
Seonghearn Lee
Keyword(s):  
Quality Factor ◽  
High Resistivity ◽  
Rf Cmos ◽  
Frequency Dependent ◽  
Factor Modeling

MEMS-based LC tank with extended tuning range for low phase-noise VCO

2015 ◽  
Vol 9 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Alessandro Cazzorla ◽  
Paola Farinelli ◽  
Laura Urbani ◽  
Fabrizio Cacciamani ◽  
Luca Pelliccia ◽  
...  
Keyword(s):  
Phase Noise ◽  
Quality Factor ◽  
Ohmic Contacts ◽  
Tuning Range ◽  
Design System ◽  
High Resistivity ◽  
Continuous Tuning ◽  
5 Ghz ◽  
Lc Tank ◽  
Low Phase Noise

This paper presents the modeling, manufacturing, and testing of a micro-electromechanical system (MEMS)-based LC tank resonator suitable for low phase-noise voltage-controlled oscillators (VCOs). The device is based on a variable MEMS varactor in series with an inductive coplanar waveguide line. Two additional parallel stubs controlled by two ohmic MEMS switches have been introduced in order to increase the resonator tunability. The device was fabricated using the FBK-irst MEMS process on high resistivity (HR) silicon substrate. Samples were manufactured with and without a 0-level quartz cap. The radio frequency characterization of the devices without 0-level cap has shown a continuous tuning range of 11.7% and a quality factor in the range of 33–38. The repeatability was also tested on four samples and the continuous tuning is 11.7 ± 2%. Experimental results on the device with a 0-level cap, show a frequency downshift of about 200 MHz and a degradation of the quality factor of about 20%. This is, most likely, due to the polymeric sealing ring as well as to a contamination of the ohmic contacts introduced by the capping procedure. A preliminary design of a MEMS-based VCO was performed using Advanced Design System and a hardwired prototype was fabricated on Surface Mount Technology on RO4350 laminate. The prototype was tested resulting in a resonance frequency of 5 GHz with a phase noise of −105 and −126 dBc at 100 KHz and 1 MHz, respectively, and a measured output power of −1 dBm.

Attenuation and dispersion of P-waves in fluid-saturated porous rocks with a distribution of coplanar cracks - scattering approach

Geophysics ◽  
2020 ◽  
pp. 1-54
Author(s):  
Yongjia Song ◽  
Jun Wang ◽  
Hengshan Hu ◽  
Bo Han
Keyword(s):  
Quality Factor ◽  
Scattering Problem ◽  
Crack Density ◽  
Relaxation Frequency ◽  
P Wave ◽  
Frequency Dependent ◽  
Low Frequencies ◽  
Attenuation And Dispersion ◽  
Dispersion And Attenuation ◽  
Coplanar Cracks

Wave-induced fluid flow (WIFF) between cracks and micro-pores is one of the major mechanisms in causing attenuation and dispersion within seismic frequency ranges. Previous non-interaction-approximation (NIA) models often assume the distribution of cracks is dilute, neglecting the influences of interacting cracks on dispersion and attenuation. To overcome this restriction, we investigate the interaction between coplanar cracks and their influences on seismic dispersion and attenuation. First, a scattering problem for a longitudinal (P) wave normally impinging on a plane with equally distributed coplanar cracks in a porous medium is solved using integral transform approach. Then, based on the solution, an effective wavenumber is derived for P-wave propagation in a porous material with coplanar cracks. It is found that the magnitude of dispersion and attenuation can significantly increase when the spacing between adjacent cracks decreases even if the crack density is unchanged. Moreover, frequency-dependent asymptotic behavior of inverse quality factor is also different from that of the NIA models at frequencies lower than the WIFF relaxation frequency. Specifically, the inverse quality factor scales with the square root of frequency at low frequencies. When the spacing between adjacent cracks is large, an additional frequency-dependent scale occurs at relatively higher frequencies (but still lower than the WIFF relaxation frequency) with inverse quality factor scales with the first power of frequency. When the spacing becomes much larger so that the interaction between the adjacent cracks is negligible, the present model exactly reduces to a NIA model for a distribution of aligned slit cracks and the first power scale can prevail attenuation within low frequencies.

Frequency‐dependent Q‐estimation of Love‐type channel waves and the application of Q‐correction to seismograms

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1773-1789 ◽  
Author(s):  
Xiao‐Ping Li ◽  
Wolfgang Schott ◽  
Horst Rüter
Keyword(s):  
Dispersion Relation ◽  
Coal Seam ◽  
Quality Factor ◽  
Wave Energy ◽  
Nonlinear Function ◽  
Ratio Method ◽  
Elastic Model ◽  
Quality Factors ◽  
Frequency Dependent ◽  
Channel Wave

We present the absorption dispersion relation of Love‐type channel waves for a simple, symmetric, homogenous, three‐layered, linear elastic model assuming that the quality factors of coal [Formula: see text] and country rock [Formula: see text] are constant. We introduce complex propagation functions into the known dispersion relation describing most of the properties of the Love‐ type channel waves. The complex dispersion relation is expanded into power series of [Formula: see text] [Formula: see text] and [Formula: see text] [Formula: see text] factor of the Love‐type channel wave). The real part of the ensuing dispersion relation gives the usual dispersion relation. The imaginary part yields the frequency relation between the quality factor of Love‐type channel waves and the constant quality factors of coal and rock. In this case, [Formula: see text] depends on the frequency because the phase velocity is a function of frequency. Therefore, the attenuation coefficient is a nonlinear function of frequency. The analysis of the analytical result shows that at high frequencies the Love‐type channel wave energy is completely propagating inside the coal seam, and hence its propagation is determined by the physical properties of the coal alone. As the frequency approaches zero, the Love‐type channel wave energy is completely propagating in the rock, since the thickness of the coal is small compared to the wavelength of the channel wave, and hence the channel wave does not “see” the coal seam. The spectral ratio method is used to estimate the frequency‐dependent quality factor [Formula: see text] of Love‐type channel waves. This technique is demonstrated by applying it first to synthetic data and then to data of a well‐designed transmission survey. Finally, we use the estimated [Formula: see text] to derive an inverse Q‐operator and apply it for Q‐correction to both data sets.

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