Standing-wave Research Articles

Microwave assisted Fraunhofer diffraction pattern in a four-level light–matter coupling scheme

The experimental realization of two-dimensional (2D) electromagnetically induced grating is explored by monitoring the Fraunhofer diffraction pattern in a microwave-driven four-level Y-type atomic medium under the action of two orthogonal standing-wave (SW) fields. Due to the position-dependent atom–field interaction, the information about the high diffraction order of the probe light can be obtained via the Fraunhofer diffraction pattern of the probe light. It is found that the diffraction behavior is significantly improved due to the joint quantum interference induced by the SW and microwave-driven cycling fields. Most importantly, the amplitude and phase diagram of the transmission function of the probe light can be modulated at a particular position and the probe energy may transfer to the high orders of the diffraction by properly adjusting the system parameters. The proposed scheme may provide a promising way to achieve highly sensitive diffraction patterns with applications in quantum information processing.

Using Local Concentration to Model the Progress of Acoustophoretic Assembly of Microspheres in Planar Standing Waves

Abstract Acoustophoretic assembly uses a standing acoustic field to move dispersed small particles into a geometric pattern. The technique relies on the acoustic radiation force, which arises from the interaction between the acoustic field and the particles, and drives the particles towards areas of low acoustophoretic potential. Acoustophoretic assembly shows potential for a wide range of applications, including organizing filler materials in composites, creating metamaterials, and fabricating functional biological tissue. However, the method has not yet been incorporated into large-scale manufacturing processes. One barrier is the incomplete understanding of the assembly process. While an ideal final pattern geometry can be calculated from the acoustic field and the material properties, there are currently no widespread metrics for measuring the progress of the pattern formation. As a result, it is difficult to know how long the acoustic field should be applied during manufacturing. Our approach uses the local particle concentration to model the acoustophoretic assembly process. We show that an expression for the time-dependent local particle concentration can be derived from the force balance on the particles and a control volume analysis. The analysis is applied to microspheres in a planar acoustic standing wave, and an analytical expression is obtained, , which yields a time parameter for pattern assembly and suggests a cut-off time. We then use the local concentration to define measurements for the quality of the assembled microsphere pattern. Experiments were carried out using polystyrene microspheres in a glycerol-water mixture to validate the theoretical results.

High-Power Terahertz Free Electron Laser via Tapering-Enhanced Superradiance

A superradiant FEL in the THz (3 THz) region is currently operating at Ariel University. It is based on the novel ORGAD accelerator, which is a hybrid linear RF photo-cathode 6 MeV electron gun. The hybrid term stands for its unique standing wave (SW)—traveling wave (TW) structure. The undulator generates spontaneous superradiance, which corresponds to spontaneous emission when the electron bunch duration is shorter than the radiated frequency, resulting in a much higher photon yield. However, the efficiency of this scheme is still quite low. In order to achieve higher emission (by improved efficiency), we intend to implement a new and promising radiative interaction scheme: tapering-enhanced superradiance (TES). This particular undulator design employs a tapered (amplitude) undulator in the zero-slippage condition to obtain a significantly more powerful and efficient THz radiation source. At the current stage, the scheme is designed for emission at approximately 0.5 THz. The design and start-to-end simulations demonstrate significant enhancement of superradiant energy and extraction efficiency using this method compared to a reference uniform case.

Asymmetric 2D diffraction grating via vortex field in an inverted-Y-type atomic system

Abstract We propose a theoretical scheme to realize two-dimensional (2D) diffraction grating in a four-level inverted-Y-type atomic system coupled by a standing-wave (SW) field and a Laguerre-Gaussian (LG) vortex field. Owing to asymmetric spatial modulation of the LG vortex field, the incident probe field can be lopsidedly diffracted into four domains and asymmetric 2D electromagnetically induced grating (EIG) is created. By adjusting the detunings of the probe field and the LG vortex field, the intensities of the LG vortex field and the coherent SW field, as well as the interaction length, the diffraction properties and efficiency can be effectively manipulated. In addition, the effect of the azimuthal parameter on the Fraunhofer diffraction of the probe field is also discussed. The scheme of symmetric 2D diffraction grating may provide a versatile platform for designing quantum devices that require asymmetric light ransmission.

A 3D Printed bi-directional Turbine for Thermoacoustic Standing Wave Environment at an Atmospheric Pressure

This paper reports a study on the use of an in-house 3D printed bi-directional turbine for energy conversion in a standing wave thermoacoustic environment that is operated at an atmospheric pressure. The 3D printed turbine was placed at two locations along the resonator and the data were recorded for several range of flow frequency and flow amplitude. It is found that maximum output is achieved when flow is not at resonance. Resonance of the standing wave inside the rig was found at 106 Hz but the bi-directional turbine performs better at a lower frequency of 85 Hz.

Simulation Study of Electromagnetic Standing Wave Method for Pre-stress Detection of Steel Strands

With the widespread application of pre-stressed technology, effective pre-stress monitoring has become a key research area in the field of health monitoring, such as bridges. This paper conducts a simulation-based validation study based on the electromagnetic standing wave pre-stress measurement method. Through the analysis of the implementation process and principles of the electromagnetic standing wave measurement method, frequency domain simulations are performed in HFSS software, and then the frequency domain results are imported into ADS for time domain simulations, ultimately verifying the feasibility of the electromagnetic standing wave pre-stress measurement method. Experimental results indicate that the electromagnetic standing wave method can achieve non-destructive and effective monitoring of in-service pre-stressed steel strands.

A Multiband Standing Wave Oscillator With Wave Pattern Tailoring for Selective Mode Excitation

A Multiband Standing Wave Oscillator With Wave Pattern Tailoring for Selective Mode Excitation

A Waveguide Inline Binary Metasurface for Wavelength-Selective Transmission and Standing Wave Focusing.

This study presents an innovative inline metasurface design for selective wavelength transmission and focusing. When integrated into optical fibers, it improves the stability and compatibility with techniques like wavelength division multiplexing and phase modulation. Precise parameters, determined through analytical calculations and simulations, allow for the design of multifunctional lenses within the optical fiber platform. The numerical results demonstrate unmodulated transmission for specific wavelengths, while others exhibit standing wave focusing with a 0.67 μm beam radius and a 0.31 μm depth of focus. This technology holds promise for applications in quantum experiments, sensing, and optical communication.

Sustainable spectrum sharing 5G network antenna design for smart city

<p>The objective of this research paper is to propose the design of an integrated circuit (IC) combined with an antenna to reduce the footprint on the Printed Circuit Board (PCB). The aim is to enhance its power, space efficiency, and sustainability in order to improve its usefulness, especially in smart city communication. This paper introduces a smart antenna design that enables message transmission and reception through multiple channels while also facilitating wireless spectrum sharing over a 5G network. The effectiveness of a sustainably designed 2 × 2 Planner array antenna is evaluated by measuring the return values (in dB) and Voltage Standing Wave Ratio (VSWR) values with respect to frequency changes. The operational frequencies of the antenna are 44.3 GHz and 35.2 GHz, achieving a maximum gain of 15.4 dB at 29 GHz. The radiation efficiency is determined to be 85% at the resonance frequencies. In future, it would be beneficial to focus on developing an antenna with similar characteristics while utilising a smaller number of elements.</p>

Simulation of Wave Propagation in Plasma-Metamaterial Composites Based on Plasma Parameters and Metamaterial Structures

Metamaterial is a left-handed medium used in antenna design to overcome the typical design's larger size and untunable nature. Because of its design with a high permittivity dielectric substrate and some deformation, the wireless sector may be able to solve this difficulty. Metamaterial antennas have a five-fold reduction in size, a higher bandwidth, a wider scanning angle, good beam performance, and electronically controlled targeting. Metamaterials antennas also improve antenna parameters such as frequency generation, gain, and bandwidth. This research aims to suggest the best metamaterials structure for improving antenna performance using plasma as a base. This study used 12 types of plasma with varying plasma frequencies and collision frequencies with four metamaterials structures: 1D-split ring structure, Symmetrical structure, Omega structure, and S structure. Computer Simulation Technology (CST) Studio Suite was used to design and simulate each structure with a sequence of plasma. At frequencies ranging from 1 GHz to 20 GHz, parameters including return loss, gain, radiation pattern, and Voltage Standing Wave Ratio (VSWR) are used to assess an antenna's performance. Due to its electromagnetic qualities, the 1D-split ring construction has a better omnidirectional figure and VSWR value of 1.0039 dB. When all criteria were considered, the best results were obtained when using a 1D-split ring structure of the Plasma 9 (plasma frequency of 3.58528 x1011 rad/s and collision frequency of 1.3349 x109 1/s) produces an efficient return loss, high gain, better VSWR and a better omnidirectional figure among the four structures evaluated.

Investigation of Split Ring Resonator Based Rectangular Micro-Strip Patch Antenna for Radar Communication

The advent of antenna technology has greatly influenced the field of wireless communication. In this paper, a novel rectangular microstrip patch antenna with split ring resonators is presented. It is intended for use in the X-band, which normally operates between 8 and 12 GHz. Split ring resonators are incorporated into the radiating patch to increase gain and frequency bandwidth. Based on Rogers TMM 10TM, a dielectric material with a relative permittivity of 9.8, the antenna is made to operate at 10.4 GHz in the X-band. Several factors, such as S-parameters, radiation pattern, Voltage Standing Wave Ratio (VSWR), gain, and directivity are used to assess the performance of the proposed antenna. The design and simulation of the antenna need the usage of High-Frequency Structure Simulator (HFSS) software. The findings imply that the suggested antenna configuration has an efficiency of 93.5% and is proved to be an excellent candidate for Radar Communication because of its wide frequency bandwidth and other performances.

Developing Highly Sensitive SAW Standing Wave Magnetic Sensor through Resonant Frequency Shift and Acoustic Energy Concentration

Developing Highly Sensitive SAW Standing Wave Magnetic Sensor through Resonant Frequency Shift and Acoustic Energy Concentration

Multipactor Thresholds Prediction for Geometries Subject to Standing Waves

Multipactor Thresholds Prediction for Geometries Subject to Standing Waves

Analyzing Troubleshooting of BTS Transmit Power and 4G LTE Coverage Area via VSWR Value Measurement

The Voltage Standing Wave Ratio (VSWR) serves as a comparative measure between transmitter and receiver voltages, impacting site transmit power. VSWR values at a Radio Base Station (RBS) are evident in feeder cable losses, jumpers, combiners, and radio antenna losses. This study aims to assess the impact of poor VSWR values on BTS transmit power and perform troubleshooting analysis on 4G signal quality and Coverage Area. The study commenced with a literature review and VSWR measurements in the Gurun Laweh Aia Pacah region. The process involved identifying VSWR issues at the BTS site, conducting a Drive Test using pocket Tems, and troubleshooting the VSWR problem. Drive Test findings encompassed areas with weak signals, BTS site data, and problematic spots. The analysis utilized applications like Tems Discovery and MapInfo Pro. Results along the Gurun Laweh Aia Pacah road showed signal strength affected by a high VSWR value of 1.6. RSRP data rated 50% in the good category, SINR at 31% in the good category, and throughput at 5% in the good category. Elevated VSWR values diminish signal range, subsequently impacting traffic metrics. Immediate VSWR troubleshooting becomes imperative; low VSWR promotes higher transmit power efficiency, while normal VSWR ensures optimal transmit power efficiency.

A switching method for traveling/standing wave transportation modes in two-dimensional acoustic fields using a dual-transducer support structure

The dual-transducer support structure discussed has the advantages of a simple structure and low cost, as well as allowing for the use of both Traveling-Wave (TW) and Standing-Wave (SW) acoustic transportation, supporting its use in pharmaceutical and biochemical analysis, for example. By adjusting the distance between the vibrating plate and the reflector which forms SW field in the y direction, the control of the position of the SW nodes or the TW component along the x direction allows the formation of a Two-Dimensional Standing Wave (2D-SW) or a Traveling Wave (TW) acoustic field, and these could be used for transportation in the x direction. It has been found that the x position of the SW nodes can be adjusted through changing the temporal phase shift, θ, which permits multiple objects to be transported using the 2D-SW mode. By comparison, TWs in the opposite direction could be generated at a pair of specific temporal phase shifts, allowing fast transportation using the TW mode. In this research work, an experiment has been carried out to transport polystyrene spheres using the two modes by programming the temporal phase shift, θ, this illustrating that precise position control of the multiple objects transported was possible using the 2D-SW mode, while high-speed transportation (up to 540 mm/s) was realized using the TW mode, showing that the dual-transducer support structure could be used effectively for accurate and fast transportation. As a fully non-contact method, the dual-transducer support structure can be seen to work in the 2D-SW mode for reaction synthesis or detection applications, and also in TW mode for rapid sample transportation applications.

Revolutionizing Physics Education: Enhancing High School Students' Understanding of Standing Wave Concepts through Mictester-Based Smartphone Experiments

The study aims to test the effectiveness of using the audio analysis software, Mictester, on smartphones in experiments on standing waves in order to improve students' understanding of concepts in high school. The sample consisted of 19 students of 11th grade at State High School 1 SoE. The instrument used was a test sheet of conceptual understanding of standing wave matter. The results show a significant improvement in students' understanding of concepts after the application of Mictester for audio analysis on Android devices/smartphones. Thus, standing wave experiments that utilize Mictesters software for audio analytics can be an alternative in physics learning, replacing conventional experimental equipment such as oscilloscopes, thereby reducing the cost of experiments.

Standing wave patterns in graphene systems studied using scanning tunneling spectroscopy

Standing wave patterns are formed near potential barriers or steps due to the interference of incident and reflected waves. Graphene systems show standing wave patterns near atomic step edges, defects, and impurities in scanning tunneling microscopy; however, there are still unexplored examples. In this study, we present our experimental results for graphene directly grown on hexagonal-BN/Cu by chemical vapor deposition. Standing wave patterns were observed in our scanning tunneling microscopy and spectroscopy, revealing linear dispersion relations with a Fermi velocity of about 106 m/s. Our study shows that graphene grown on hexagonal-BN/Cu provides a useful platform to study the electronic characteristics of graphene systems.

Standing waves on holidays

Standing waves are a common phenomenon in nature, but sometimes difficult to understand by the students. Many of them do not realise, for example, that the sound coming from the musical instruments is due to standing waves that are formed in strings, membranes, or cavities on those instruments. In this paper, we describe a simple activity that occurred in a circular pool during holidays which excited people for generating standing waves with their own body. This was also an opportunity for talking about this phenomenon with young people and make simple calculations of the speed of waves in shallow water. This is an example that summertime is not just for relaxing and teachers may find good examples of applied physics to bring to their classes and help students to better understand physics contents.

Wakefield damping in a distributed coupling linear accelerator

The number of cells in a π-mode standing wave (SW) accelerating structure for the Compact Linear Collider (CLIC) project is limited by mode overlap with nearby modes. The distributed coupling scheme avoids mode overlap by treating each cell as independent. Designs of cells suitable for distributed coupling with strong wakefield suppression by waveguide damping have not previously been studied. In this paper we develop a SW cell to be used in a distributed coupling structure that can satisfy the CLIC transverse wake potential limit. From the middle cell of the CLIC-G* traveling wave (TW) structure, a SW cell is designed and then adapted to perform as a cell in a distributed coupling structure. Its wake potentials in an ideal case of open boundaries are reduced to satisfy the wake potential threshold. An electric boundary is added to the model to simulate total reflection at the distribution network. A horizontal coupler cell that connects to the distribution network such that the reflected wakefields remain similar to the open boundary case is simulated. A triplet module which takes advantage of cell-to-cell coupling to reduce reflected wake potential is presented.

Efficient two-dimensional Fraunhofer diffraction pattern via electron spin coherence

In this letter, we have discussed the two-dimensional diffraction pattern via electron spin coherence in a GaAs quantum dot. Impulsive stimulated Raman excitation utilizing coherent optical fields is employed for the purpose of regulating the electron spin coherence within a charged ensemble of GaAs quantum dots, by means of an intermediate charged exciton (trion) state. We show that for the coupling two-dimensional standing wave (SW) field in the x and y directions, the two-dimensional Fraunhofer pattern can be formed for a weak probe light. By using the experimental parameters and controlling the Rabi frequency of the SW field and relative phase between applied lights, the symmetry and asymmetry diffraction pattern are obtained for the weak probe light due to the four-wave mixing mechanism. Our proposed model may have potential applications in high-capacity optical communications and quantum information technologies.