Characteristics of instantaneous resonant modes in simple dense fluids with short-ranged repulsive interactions

Dense fluids and liquids molecules are in constant interaction; hence, they do not fit into the Boltzmann’s picture of a clearcut separation between free-streaming and collisional interactions. Since the interactions are soft and do not involve large scattering angles, an effective way of describing dense fluids is to formulate stochastic models of particle motion, as pioneered by Einstein’s theory of Brownian motion and later extended by Paul Langevin. Besides its practical value for the study of the kinetic theory of dense fluids, Brownian motion bears a central place in the historical development of kinetic theory. Among others, it provided conclusive evidence in favor of the atomistic theory of matter. This chapter introduces the basic notions of stochastic dynamics and its connection with other important kinetic equations, primarily the Fokker–Planck equation, which bear a complementary role to the Boltzmann equation in the kinetic theory of dense fluids.

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Design of Wideband Bandpass Filter Based on Corrugated Disk Resonator with Multiple Resonant Modes

Materials ◽

10.3390/ma14102614 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2614

Author(s):

Qian Yang ◽

Shuangyang Liu ◽

Hongyu Shi ◽

Kai-Da Xu ◽

Xinyue Dai ◽

...

Keyword(s):

Theoretical Analysis ◽

Bandpass Filter ◽

Design Method ◽

Center Frequency ◽

Localized Surface Plasmons ◽

Metallic Structure ◽

Disk Resonator ◽

Resonant Frequencies ◽

Resonant Modes ◽

Via Holes

A corrugated disk resonator with eight grooves is proposed for wideband bandpass filter (BPF) design. Due to the spoof localized surface plasmons resonances of the corrugated metallic structure, the dipole, quadrupole, hexapole modes, and a fundamental mode excited by the introduced short-circuited via holes are employed to realize four transmission poles (TPs) in the passband. The theoretical analysis is described by the electric field and current distributions on the resonator. The resonant frequencies can be tuned easily by the parameters of the structure, which can be used to adjust the center frequency and bandwidth of the BPF freely. Furthermore, two resonators are cascaded to obtain eight TPs to improve the selectivity performance. Finally, three fabricated filters demonstrate the design method.

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Highly efficient artificial magnetic conductor enabled CPW fed compact antenna for BAN wearable applications

Frequenz ◽

10.1515/freq-2020-0115 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Maksud Alam ◽

Amber Khan ◽

Mainuddin ◽

Binod Kumar Kanaujia ◽

Mirza Tariq Beg

Keyword(s):

Coplanar Waveguide ◽

Split Ring Resonator ◽

Area Network ◽

Network Analyzer ◽

Magnetic Conductor ◽

Split Ring ◽

Artificial Magnetic Conductor ◽

Compact Antenna ◽

Resonant Modes ◽

Miniaturized Antenna

AbstractIn this paper a coplanar waveguide feed (CPW) monopole antenna backed with artificial magnetic conductor (AMC) structure for efficient radiation has been presented for off-body wearable applications. A split ring resonator (SRR) having thiner and longer lines to produce higher inductance and six splits with smaller gaps for high capacitance have been placed underneath CPW fed monopole to achieve resonance mode at a lower frequency. Higher values of inductance and capacitance produce resonant modes at relatively lower frequencies resulting in highly miniaturized antenna. The desired −10dB S11 bandwidth has been optimized firstly, by tuning/optimizing flow of surface currents with the help of several slots/slits and later by realizing AMC reflector with the help of full ground backed foam. The proposed antenna covers 2.45 GHz industrial, scientific and medical (ISM) band body area network (BAN) application and posses good front to back ratio (FBR) and thereby low and acceptable values of specific absorption rate (SAR). The proposed antenna has been designed and simulated using Ansys high frequency structured simulator and tested using vector network analyzer and anechoic chamber. The simulated and measured results well agree with each other.

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Symmetry-tailored patterns and polarizations of single-photon emission

Nanophotonics ◽

10.1515/nanoph-2020-0208 ◽

2020 ◽

Vol 9 (11) ◽

pp. 3557-3565

Author(s):

Guorui Zhang ◽

Ying Gu ◽

Qihuang Gong ◽

Jianjun Chen

Keyword(s):

Single Photon ◽

Photon Emission ◽

Silver Nanowire ◽

Emission Rates ◽

Single Photon Emission ◽

Emission Pattern ◽

Single Photon Emitters ◽

Resonant Modes ◽

Oriented Dipole ◽

Centrally Symmetric

AbstractDue to small optical mode volumes and linear polarizations of surface-plasmon-polariton (SPP) resonant modes in metallic antennas, it is very difficult to obtain complex emission patterns and polarizations for single-photon emitters. Herein, nonresonant enhancement in a silver nanowire is used to both enhance emission rates and extract a z-oriented dipole, and then the symmetry of metallic nanostructures is proposed to tailor the patterns and polarizations of single-photon emission. The emission pattern of a quantum dot located close to a metallic nanostructure with a symmetric axis is split into multiple flaps. The number of splitting flaps is equal to the order of the symmetric axis. Moreover, the electric vectors of the emitted photons become centrally symmetric about the symmetric axis. The above phenomena are well explained by both a simulation and an image dipole model. The structural-symmetry-tailoring mechanism may open up a new avenue in the design of multifunctional and novel quantum-plasmonic devices.

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Small-Sized Interferometer with Fabry–Perot Resonators for Gravitational Wave Detection

Sensors ◽

10.3390/s21051877 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1877

Author(s):

Nikolai Petrov ◽

Vladislav Pustovoit

Keyword(s):

Correlation Function ◽

Gravitational Waves ◽

Laser Interferometer ◽

Zero Order ◽

Wave Detection ◽

Resonant Modes ◽

Fabry Perot ◽

Spatially Distributed ◽

Wave Laser ◽

Higher Sensitivity

It is highly desirable to have a compact laser interferometer for detecting gravitational waves. Here, a small-sized tabletop laser interferometer with Fabry–Perot resonators consisting of two spatially distributed “mirrors” for detecting gravitational waves is proposed. It is shown that the spectral resolution of 10−23 cm−1 can be achieved at a distance between mirrors of only 1–3 m. The influence of light absorption in crystals on the limiting resolution of such resonators is also studied. A higher sensitivity of the interferometer to shorter-wave laser radiation is shown. A method for detecting gravitational waves is proposed based on the measurement of the correlation function of the radiation intensities of non-zero-order resonant modes from the two arms of the Mach–Zehnder interferometer.

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A printed multiband MIMO antenna with decoupling element

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078719000096 ◽

2019 ◽

Vol 11 (4) ◽

pp. 413-419 ◽

Cited By ~ 1

Author(s):

Ziyu Xu ◽

Qisheng Zhang ◽

Linyan Guo

Keyword(s):

Mutual Coupling ◽

Surface Current ◽

Antenna System ◽

Antenna Element ◽

Coupling Mechanism ◽

Mimo Antenna ◽

Resonant Modes ◽

Monopole Antennas ◽

Input Multiple Output ◽

Ground Plate

AbstractA printed multiband Multi-Input Multiple-Output (MIMO) antenna is proposed in this paper. This MIMO antenna system comprises two symmetric printed monopole antennas. Each antenna element consists of multiple bend lines, producing four resonant modes and covering the GSM900, PCS, LTE2300, and 5G bands. Simulated and measured results prove that the proposed MIMO antenna can be applied to traditional 2G, 3G, 4G, and present 5G mobile communication. By etching four inverted L-shaped grooves on its ground plate, mutual coupling between the adjacent antenna elements has been suppressed. This makes the |S21| at all four resonant modes is lower than −40 dB. In addition, its low coupling mechanism has been analyzed by surface current distribution. The designed multiband MIMO antenna provides an idea of reference to realize low mutual coupling between antenna elements, which is also realizable in infrared or optical regimes with appropriate designs.

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