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Influences of relative humidity on the quality factors of MEMS cantilever resonators in gas rarefaction
摘要： In this paper, the effect of relative humidity of moist air is discussed on the quality factor (Q factor) of micro-electro-mechanical systems (MEMS) cantilever resonators in wide range of gas rarefaction (ambient pressure and accommodation coefficients, ACs). The modified molecular gas lubrication (MMGL) equation is used to model the squeeze film damping problem of MEMS cantilever resonators. Dynamic viscosity and Poiseuille flow rate are used to modify the MMGL equation to consider the coupled effects of relative humidity and gas rarefaction. Thermoelastic damping and anchor loss, which are dominant damping mechanisms of MEMS cantilever resonators, are also included to calculate total Q factor. Thus, the influences of relative humidity are discussed on the Q factors of MEMS cantilever resonators in wide range of gas rarefaction and dimension of cantilever. The results showed that the Q factor decreases as relative humidity increases in wide range of gas rarefaction (pressure, and ACs) and dimension of cantilever (length, width, and thickness). The influences of relative humidity on the Q factor become more significantly in larger length, larger width, smaller thickness of cantilever, and higher gas rarefaction (lower pressure and ACs). Whereas, the influences of relative humidity on the Q factor reduce or are neglected in smaller length, larger thickness of cantilever and lower gas rarefaction (higher pressure and ACs).
关键词： Anchor loss,Relative humidity,Quality factor,Gas rarefaction,Squeeze film damping,Thermoelastic damping,MEMS cantilever resonators
更新于2025-09-10 09:29:36
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A NOVEL RECONFIGURABLE UWB FILTERING-ANTENNA WITH DUAL SHARP BAND NOTCHES USING DOUBLE SPLIT RING RESONATORS
摘要： This study presents a novel technique for designing an ultra-wideband (UWB) filtering-antenna with dual sharp band notches. This design is composed of a modified monopole antenna integrated with resonant structures. The monopole antenna is modified using microstrip transition between the feedline and the patch. In addition, block with a triangle-shaped slot is loaded on each side of the ordinary circular patch to produce wide bandwidth with better return loss and higher frequency skirt selectivity. The resonant structures are constructed using two double split ring resonators (DSRR) loaded above the ground plane of the antenna to produce dual band notches and filter out WiMAX (3.3–3.7 GHz) and HiperLAN2 (5.4–5.7 GHz) frequencies. The band notch position is controlled by varying the length of the DSRR. The reconfigurability feature is achieved by using two PIN diode switches employed in the two DSRR. The measured results show that the proposed filtering-antenna provides wide impedance bandwidth from 2.58 to 15.5 GHz with controllable dual sharp band notches for WiMAX and HiperLAN, peak realized gain of 4.96 dB and omnidirectional radiation pattern.
关键词： double split ring resonators (DSRR),dual sharp band notches,filtering-antenna,PIN diode switches,WiMAX,HiperLAN2,Ultra-wideband (UWB)
更新于2025-09-10 09:29:36
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Fabrication and Measurement of a Suspended Nanochannel Microbridge Resonator Monolithically Integrated with CMOS Readout Circuitry
摘要： We present the fabrication and characterization of a suspended microbridge resonator with an embedded nanochannel. The suspended microbridge resonator is electrostatically actuated, capacitively sensed, and monolithically integrated with complementary metal-oxide-semiconductor (CMOS) readout circuitry. The device is fabricated using the back end of line (BEOL) layers of the AMS 0.35 μm commercial CMOS technology, interconnecting two metal layers with a contact layer. The fabricated device has a 6 fL capacity and has one of the smallest embedded channels so far. It is able to attain a mass sensitivity of 25 ag/Hz using a fully integrable electrical transduction.
关键词： nanochannel,NEMS,suspended channel,resonators,CMOS-NEMS
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Decoupling of Two Closely Located Dipoles Using Metasurfaces of Resonant Dipoles and Split-Loop Resonators
摘要： We present numerical and experimental validations of decoupling between two very closely located dipole antennas using metasurfaces. Compared to decoupling by a single passive scatterer, decoupling by metasurfaces reduces negative effects over the radiated signal. Simulation and measurement results demonstrate the possibility of decoupling between two active dipoles using metasurfaces of passive dipoles and split-loop resonators (SLRs).
关键词： dipole antennas,MRI,split-loop resonators,decoupling,metasurfaces
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Reduction of the beam-coupling impedance in accelerating structures using metamaterial-based absorbers
摘要： Resistive-wall impedance constitutes a significant percentage of the total beam-coupling impedance budget of an accelerator. Under extreme conditions, like large power handling and ultra-high vacuum, metamaterial-based absorbers can represent a valid alternative to other approaches for impedance mitigation in specific accelerator components, like resonant (parasitic) cavities or collimators operating along the beam line. We design sub-wavelength 2D metallic resonant structures based on split rings or on 3D hyperbolic tapered waveguide arrays that can be employed as mode dampers in accelerating structures. A number of prototypes are fabricated and then measured in a “test model” pillbox cavity.
关键词： accelerators,hyperbolic metamaterials,metamaterials,beam-coupling impedance,split-ring resonators
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Miramar Beach, FL, USA (2018.8.22-2018.8.24)] 2018 IEEE Research and Applications of Photonics In Defense Conference (RAPID) - Wideband Mid-IR Semiconductor Resonant Reflectors
摘要： Mid-IR resonant reflectors are presented offering wideband polarized and unpolarized responses. Devices are fabricated from durable and commercially available IR transparent semiconductor materials, offering the possibility of rugged and economical opto-electronic integration.
关键词： Nanophotonics,Optical resonators,Micromirrors
更新于2025-09-10 09:29:36
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Dual wavelength optical duobinary modulation using GaAs–AlGaAs microring resonator
摘要： In this article, optical duobinary modulation technique has been used for modulating the dual-wavelength optical signal generated by the microring resonator system. The optical signals are de-multiplexed to two different optical signals with center wavelength of 1540 and 1545 nm afterward, these are modulated and transmitted over an optical fiber communication system, where the high performance of the transmitted signals is obtained. The NRZ binary signals are used to modulate the optical signals. The high-quality factor and performance of the system has been investigated by applying an optimization through the system parameters, where significant improvement could be obtained and highest quality factor of 32.871 shows the successful transmission. The second wavelength of the dual-wavelength has undergone the same modulation technique and has experienced the optical transmission after the system optimization has been performed, where the quality factor for the received optical signal at 1545 nm center wavelength is 39.282. These results show the introduced modulation technique is suitable to apply for the optical signals generated by the microring resonators.
关键词： microring resonators,dual-wavelength,Optical duobinary modulation technique
更新于2025-09-10 09:29:36
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Singular pole and enhanced sensitivity of PT-symmetric layered structure with resonators
摘要： In order to achieve enhanced transmittance of parity-time (PT)-symmetric system, we design a layered PT-symmetric structure including resonators. We use the scatter matrix method to study the optical properties of the designed structure under the modulation of resonators. The structure system takes on a singular pole effect, i.e., the huge re?ectance and transmittance occur at a special wavelength and period number. The ?eld distribution reveals that the singular pole results from the coupling resonance of single cavity and the whole structure. Because of the coupling resonance, the total gain in layer A is much larger than the total loss in layer C. The re?ectance and transmittance at the singular pole take on a high sensitivity on the refraction index of the resonators.
关键词： singular pole effect,coupling resonance,resonators,scatter matrix method,PT-symmetric system
更新于2025-09-10 09:29:36
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Integrated On-chip Bragg Time-Delay System for Thermo-Optical Control of a Microwave Antenna
摘要： This theoretical modeling-and-simulation paper presents designs and projected performance of ~1550-nm silicon-on-insulator beamsteering of a microwave phased-array antenna by the use of true time delays. The tunable on-chip optical delay line is a cascade connection of waveguide Bragg grating resonators (WBGRs) separated by a piece of straight waveguide. The notch in the reflectivity spectrum is translated along the wavelength axis by means of a low-power TO heater stripe atop the grating, inducing a time delay that depends upon the line position of the WBGR affected by TO switching. The filter resonator is a new in-guide array of identical Bragg structures, each one comprising N closely coupled phase-shifted Bragg-grating resonators. The length of each grating cavity in an N group is chosen according to the Butterworth filter technique to provide one resonant spectral profile with 40 GHz optical bandwidth. Finally, we examined the performances of the beamformer system operating in the X and Ku bands, respectively. The investigation demonstrated that steering angles up to 48° are feasible by assuming a minimum steering angle of 8° and a minimum WBGR spacing of about 354 and 236 μm for X and Ku bands, respectively.
关键词： Bragg grating resonators,Microwave Photonics,True Time Delays
更新于2025-09-10 09:29:36
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Improved design of CELC meta-resonators for bandwidth improvement and miniaturization of patch antenna
摘要： For metamaterial resonators, the essential figure of merit is its effective medium ratio (EMR), which is defined as the ratio of the resonant wavelength and lattice constant. In this paper, an altered topology of the electric-inductive–capacitive (ELC) metamaterial with an improved EMR is proposed. The proposed structure shrinks the electrical footprint of the conventional ELC resonator by accommodating additional inductance by meandering the arms of the resonator and fitting interdigital capacitors in the capacitive gap. The metamaterial properties of the proposed structure are investigated by parameter extraction, and analytical formulations are carried out for finding its resonant frequency. The proposed metamaterial structure is employed for performance enhancement and miniaturization of a standard patch antenna. A 3 × 4 array of the modified complementary resonators is etched in the ground plane of a patch antenna. A significant 293% improvement in bandwidth, with a miniaturization factor (unloaded frequency/loaded frequency) of 1.33 is achieved. The entire antenna resides in a small area of 37.5 mm × 37.5 mm. The design is substantiated both by simulation and experimental results, which complement each other. The presented design can be used for Mobile WiMAX (2.5–2.69 GHz) applications.
关键词： ELC resonator,bandwidth improvement,patch antenna,metamaterial resonators,miniaturization
更新于2025-09-10 09:29:36