Generation of Intense Low-Frequency Collimated Sound Beams by Nonlinear Acoustics and Detection by a Millimeter-Wave Vibrometer

2010 ◽  
Author(s):  
John A. Scales ◽  
Martin Smith ◽  
Brian Zadler
Keyword(s):  
Millimeter Wave ◽  
Low Frequency ◽  
Nonlinear Acoustics ◽  
Sound Beams

scholarly journals Research on 5G Millimeter Wave Channel Estimation Algorithm

2019 ◽  
pp. 74-77
Author(s):  
Xu Shuang
Keyword(s):  
Channel Estimation ◽  
Millimeter Wave ◽  
Massive Mimo ◽  
Large Scale ◽  
Low Frequency ◽  
Estimation Algorithm ◽  
Simulation Research ◽  
Wave Technology ◽  
Wave Channel ◽  
Mimo Technology

With the explosive growth in the number of communication users and the huge demand for data from users, Limited low-frequency resources have been far from being satisfied by users. The combination of Massive MIMO technology and millimeter-wave technology has brought new hope to users. In this paper, several basic algorithms are placed under the millimeter wave large-scale antenna channel for simulation research.

A Millimeter-Wave WPAN Adaptive Phased Array Control Method Using Low-Frequency Part of Signal for Self-Directed System

2015 ◽  
Vol 63 (8) ◽  
pp. 2682-2691 ◽  
Author(s):  
Tuan Thanh Ta ◽  
Shoichi Tanifuji ◽  
Akinori Taira ◽  
Suguru Kameda ◽  
Noriharu Suematsu ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Phased Array ◽  
Control Method ◽  
Low Frequency ◽  
Directed System

Sensor Location Analysis in Nonlinear Acoustics Used for Damage Detection in Composite Chiral Sandwich Panels

2012 ◽  
Vol 83 ◽  
pp. 223-231 ◽  
Author(s):  
Andrzej Klepka ◽  
Wieslaw Jerzy Staszewski ◽  
Dario di Maio ◽  
Fabrizio Scarpa ◽  
Kong Fah Tee ◽  
...  
Keyword(s):  
Damage Detection ◽  
High Frequency ◽  
Low Frequency ◽  
Nonlinear Acoustics ◽  
Location Analysis ◽  
Sensor Location ◽  
Ultrasonic Sensing ◽  
Low Profile ◽  
Frequency Excitation ◽  
Vibration Wave

This paper demonstrates damage detection in a smart sandwich panel with integrated piezoceramic transducers. The panel is built from a chiral honeycomb and two composite skins. A low-profile, surface-bonded piezoceramic transducer is used for high-frequency ultrasonic excitation. Low-frequency excitation is performed using a piezoceramic stack actuator. Ultrasonic sensing is performed using laser vibrometry. Nonlinear acoustics is applied for damage detection. The study is focused on sensor location analysis with respect to vibro-acoustic wave modulations. The paper demonstrates that when structure is damaged, the high-frequency “weak” ultrasonic wave is modulated by the low-frequency “strong” vibration wave. As a result frequency sidebands can be observed around the main acoustic harmonic in the spectrum of the ultrasonic signal. However, intensity of modulation strongly depends on sensor location.

scholarly journals Design and Simulation of millimeter wave Mylar based flexible Antenna for 5G wireless Applications

2020 ◽  
Vol 9 (3) ◽  
pp. 606-610
Keyword(s):  
Wave Propagation ◽  
Millimeter Wave ◽  
Low Frequency ◽  
Large Data ◽  
Impedance Bandwidth ◽  
Ground Structure ◽  
Wireless Applications ◽  
Microstrip Patch ◽  
High Impedance ◽  
Flexible Antenna

The millimeter wave (mm-wave) is expected to play a crucial role in providing broad frequency bandwidth for large data transmission. The restrictions of wave propagation are anticipated to get eliminated in mm-wave propagation through the assistance of antenna technologies. The higher frequency spectrum prevalence of the 5G applications are likely to be dependent on a small advanced antenna technology. This paper presents an antenna design which uses Mylar as substrate for the 5G wireless applications. The structure of the antenna adopted here is of a T-shaped patch designed with ideal symmetrical slot structures. To increase the bandwidth the idea of defective ground structure (DGS) is used. The antenna model discussed here shows a high impedance bandwidth and a fair radiation pattern in the required direction with a maximum gain of 8.35dB at 28 GHz frequency. The proposed antenna is compared with the basic microstrip patch antenna which is designed at low frequency to prove that the bandwidth is enhanced and so other parameters in the proposed antenna such that it is suitable for mm-wave 5G wireless applications.

Impact Damage Detection in Composite Chiral Sandwich Panels

2012 ◽  
Vol 518 ◽  
pp. 160-167 ◽  
Author(s):  
Andrzej Klepka ◽  
Wieslaw Jerzy Staszewski ◽  
T. Uhl ◽  
Dario di Maio ◽  
Fabrizio Scarpa ◽  
...  
Keyword(s):  
Damage Detection ◽  
Ultrasonic Wave ◽  
High Frequency ◽  
Impact Damage ◽  
Low Frequency ◽  
Nonlinear Acoustics ◽  
Composite Panel ◽  
Chiral Structures ◽  
Low Frequency Vibration ◽  
Vibration Wave

This paper demonstrates impact damage detection in a composite sandwich panel. The panel is built from a chiral honeycomb and two composite skins. Chiral structures are a subset of auxetic solids exhibiting counterintuitive deformation mechanism and rotative but not reflective symmetry. Damage detection is performed using nonlinear acoustics,involves combined vibro-acoustic interaction of high-frequency ultrasonic wave and low-frequency vibration excitation. High-and low-frequency excitations are introduced to the panel using a low-profile piezoceramic transducer and an electromagnetic shaker, respectively. Vibro-acoustic modulated responses are measured using laser vibrometry. The methods used for impact damage detection clearly reveal de-bonding in the composite panel. The high-frequency weak ultrasonic wave is also modulated by the low-frequency strong vibration wave when nonlinear acoustics is used for damage detection. As a result frequency sidebands can be observed around the main acoustic harmonic in the spectrum of the ultrasonic signal.

Millimeter-Wave Assisted Sintering of Polycrystalline Yttria for Laser Host Material

2007 ◽  
Vol 561-565 ◽  
pp. 511-514
Author(s):  
Melissa K. Hornstein ◽  
Ralph W. Bruce ◽  
Arne W. Fliflet ◽  
Steven H. Gold ◽  
Manfred Kahn ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Continuous Wave ◽  
Microwave Sintering ◽  
Low Frequency ◽  
High Strength ◽  
High Energy ◽  
Processing Temperature ◽  
Thermal Gradients ◽  
Host Materials ◽  
Crystal Laser

We report an investigation of millimeter-wave processing of yttria for fabrication of transparent, high-strength polycrystalline laser hosts for high energy laser (HEL) applications. Advantages of polycrystalline, compared to single-crystal laser host materials, include lower processing temperature, higher gain with flexibility of higher dopant concentrations, cheaper fabrication, and larger-size devices. Millimeter-wave processing is an alternative method to solve the problems of both conventional vacuum and low-frequency microwave sintering, such as low heating rate, poor coupling and thermal gradients. A major component of the millimeter-wave processing facility is a 20-kW, continuous-wave, 83-GHz gyrotron oscillator. Yttria has been successfully sintered with millimeter-wave beams with up to 99% theoretical density. A partially transparent yttria sample has also been achieved using the millimeter-wave sintering process [1]. Several factors impact the quality of the sintered material including the presence of agglomerates, impurities, processing atmosphere, sintering aids, and thermal gradients. Efforts to improve the transparency will be discussed.

scholarly journals Integrated Millimeter-Wave Wideband End-Fire 5G Beam Steerable Array and Low-Frequency 4G LTE Antenna in Mobile Terminals

2019 ◽  
Vol 68 (4) ◽  
pp. 4042-4046 ◽  
Author(s):  
Mohammad Mehdi Samadi Taheri ◽  
Abdolali Abdipour ◽  
Shuai Zhang ◽  
Gert Frolund Pedersen
Keyword(s):  
Millimeter Wave ◽  
Low Frequency ◽  
Mobile Terminals ◽  
4G Lte
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