Q factor

About: Q factor is a research topic. Over the lifetime, 8387 publications have been published within this topic receiving 163135 citations. The topic is also known as: Q factor.

Quality Factor Analysis of Switched-Segmented Inductor Structure in Low-Power LC Dual-band VCO Application

Abstract: The switched-segmented inductor structure utilizing the quality factor enhancement effect at high frequency in contrast to conventional transformer-based resonator is proposed, while circumventing degradation of quality factor due to inevitable eddy current. Through the simulated analysis of quality of the proposed inductor, a dual-band VCO with proper varactors and SCA configuration has been designed, showing its advantage on lower power consumption. The VCO implemented in 130-nm UMC technology achieves frequency tuning ranges of 3.7 - 4.23 GHz and 7.2 GHz - 9.1 GHz with corresponding phase noise values of -115.7 dBc/Hz at 3.77 GHz and -108.66 dBc/Hz at 8.26 GHz. The VCO’s core area is 0.15mm ² .

Ultrahigh-Q Guided Mode Resonances in An All-dielectric Metasurface

Abstract: Abstract High quality (Q) factor optical resonators are indispensable for many photonic devices. While very large Q-factors can be obtained theoretically in guided mode settings, free-space implementations suffer from various limitations on the narrowest possible linewidth in real experiments. In these devices, the largest Q-factors are hindered by radiation loss induced by fabrication disorder. Complex photonic designs have been explored to enhance this response through either delicate engineering the topological features or carefully breaking symmetries. Here, we put forward a simple strategy to enable ultrahigh-Q guided-mode resonances in all-dielectric metasurfaces without breaking symmetry or carefully engineering topological quantities. We introduce a patterned perturbation layer on top of a multilayer waveguide system, aimed at exciting tailored guided-mode resonances from free space. We demonstrate that the associated Q-factors are inversely proportional to the perturbation squared, suggesting a simple way of achieving extremely high-Q resonances as the perturbation is reduced. The resonant wavelength can be conveniently tuned through material or structural parameters, such as the thickness and refractive index or the metasurface period, within a robust design strategy amenable for implementation in various platforms. We experimentally demonstrate such high-Q resonances at telecom wavelengths by fabricating a low-index photoresist layer photonic crystal slab on top of a 220nm top layer SOI substrate. The measurements show Q-factors up to 2.39x10 5 , comparable to the largest Q-factor obtained by topological engineering, while the resonant wavelength is tuned by varying the lattice constant of the top perturbation layer. Our results hold great promise for exciting applications, such as sensors and filters.

Radiation Q of a Thin Circular Loop Antenna with Magnetic-Frill Excitation

Abstract: In this paper, the radiation Q of a circular loop antenna excited by a magnetic-frill source is presented. The circular loop current is also expressed as a superposition of symmetric dipole and anti-symmetric loop mode currents. The radiation Q is then compared with the quality factors of the loop currents when either the dipole mode or the loop mode current is assumed present

Design of an isolated capacitor cell for three-dimensional RF circuit integration

Abstract: A compact multilayer capacitor cell isolated with perforated ground was designed and fabricated using low-temperature ceramic co-firing (LTCC) technology for three-dimensional (3D) RF circuit application. The vertical transmission from any interferer placed 114 μm above the capacitor cell and the lateral transmission from any interferer 300 μm apart from the cell were controlled below −20 dB up to 15 GHz. The 2.8-pF capacitor shielded with perforated ground of 600-μm square edge and 800-μm pitch revealed a self-resonant frequency (SRF) of 7.6 GHz and Q factor of over 190 up to 3 GHz, which is an improvement of SRF by 0.8 GHz and Q factor by 224%, compared to the capacitor with a conventional blanket ground. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 484–486, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11096

Q-Factor Performance Analysis of Spiral Inductors Using Multilayer Structures

Abstract: The great flexibility of three-dimensional multilayer technology which newly developed spiral inductors have been designed and optimized. The chosen approach for the spiral implementation loaded is a coplanar wave guide (CPW) transmission lines. The multilayer spiral inductors are very compact and having resonant frequency band between 5 GHz to 70 GHz. The area of multilayer inductor is nearly four times smaller compared to planar design in maintaining the same performance. CST software was used for electromagnetic(EM) simulation and the multilayer inductors are analyzed using EM analysis. These miniaturized inductors are designed using a combination of three metals (Au) and three polyimide dielectric layers on semi-insulating GaAs substrates. The related layout materials in integrated circuits and the effect of the inductor Q-factor on the performance of radio-frequency (RF) is discussed. Circuit design features such as minimum inductors area, the thickness of dielectric layers, and the important effect of metals and substrates loss on the inductor aspects are being addressed.