Measurement methods of a half-wavelength voltage and a chirp parameter for Mach-Zehnder optical modulators in high-frequency radio on fibre (RoF) systems

2017 ◽  
Keyword(s):  
High Frequency ◽  
Measurement Methods ◽  
Optical Modulators ◽  
Half Wavelength

scholarly journals Comparison of velocity and turbulence profiles obtained with a Vectrino Profiler and PIV

2018 ◽  
Vol 40 ◽  
pp. 05070
Author(s):  
Jay Lacey ◽  
Jason Duguay ◽  
Bruce MacVicar
Keyword(s):  
High Frequency ◽  
Laboratory Experiments ◽  
Measurement Techniques ◽  
Measurement Methods ◽  
Doppler Velocity ◽  
Sweet Spot ◽  
Turbulence Statistics ◽  
Significant Bias ◽  
Turbulent Statistics ◽  
Background Turbulence

Laboratory experiments were carried out in a small openchannel hydraulic flume at the Université de Sherbrooke. A PIV and an acoustic Doppler velocity profiler (Vectrino II (VII)) were used to measure high frequency velocities in profiles along the centreline of a small openchannel flume. Two background turbulence levels were tested. Comparisons were made of mean and turbulent statistics obtained with the two measurement techniques. The results show reasonable agreement between mean streamwise and lateral velocities measured with the PIV and VII near the “sweet spot” of the VII. In contrast, mean vertical velocities deviate substantially between the two measurement methods. Turbulence statistics have somewhat similar profile shapes, yet significant bias is observed between the two measurement methods.

scholarly journals Compact Rhombus Ring Dual Frequency Microstrip Antenna for Wireless Applications

2019 ◽  
Vol 9 (2S3) ◽  
pp. 213-216
Keyword(s):  
Patch Antenna ◽  
High Frequency ◽  
Microstrip Patch Antenna ◽  
Dual Frequency ◽  
Polar Plot ◽  
Wireless Applications ◽  
Microstrip Patch ◽  
Half Wavelength ◽  
Low Profile ◽  
Measured Length

In paper, a low profile microstrip patch antenna with rhombus model is designed at an running frequency at 2.4 GHz, 5.2 GHz. Microstrip Patch Antenna are suited to non-plane and plane areas, uncomplicated and effortless to design by used Printed Circuit Technology, it is a mechanically vigorous when it is ascended on rigid places and when the particular patch design model and dimension were selected, it has adjustable in view of resonance frequency, radiation design, impedance and polarization. High Frequency Structural Simulator (HFSS) is a definite component method solver for structures of EM (electromagnetic). The outcome values are discussed and analyzed in view of S11 (Return Loss), 3D Polar Plot, Radiation design and Gain. The value of S11 comes out to be -14.16dB for the designed antenna. The antenna measured length is nearly half wavelength in the dielectric, it is a highly censorious parameter, which governs the antenna resonant frequency. And the final values are simulated using High Frequency Structural Simulator

scholarly journals Coplanar Stripline-Fed Wideband Yagi Dipole Antenna with Filtering-Radiating Performance

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1258
Author(s):  
Yong Chen ◽  
Gege Lu ◽  
Shiyan Wang ◽  
Jianpeng Wang
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Frequency Selectivity ◽  
Antenna Design ◽  
Initial Structure ◽  
Coplanar Stripline ◽  
Half Wavelength ◽  
Yagi Antenna ◽  
Operating Bandwidth ◽  
Good Agreement

In this article, a wideband filtering-radiating Yagi dipole antenna with the coplanar stripline (CPS) excitation form is investigated, designed, and fabricated. By introducing an open-circuited half-wavelength resonator between the CPS structure and dipole, the gain selectivity has been improved and the operating bandwidth is simultaneously enhanced. Then, the intrinsic filtering-radiating performance of Yagi antenna is studied. By implementing a reflector on initial structure, it is observed that two radiation nulls appear at both lower and upper gain passband edges, respectively. Moreover, in order to improve the selectivity in the upper stopband, a pair of U-shaped resonators are employed and coupled to CPS directly. As such, the antenna design is finally completed with expected characteristics. To verify the feasibility of the proposed scheme, a filtering Yagi antenna prototype with a wide bandwidth covering from 3.64 GHz to 4.38 GHz is designed, fabricated, and measured. Both simulated and measured results are found to be in good agreement, thus demonstrating that the presented antenna has the performances of high frequency selectivity and stable in-band gain.

High-Frequency, Half-Wavelength Power Transmission Scheme

2017 ◽  
Vol 32 (1) ◽  
pp. 279-284 ◽  
Author(s):  
Yang Wang ◽  
Wilsun Xu ◽  
Yun Wei Li ◽  
Tian Hao
Keyword(s):  
High Frequency ◽  
Power Transmission ◽  
Transmission Scheme ◽  
Half Wavelength

scholarly journals Performance of Frequency Anti-Islanding Protection Considering Different Frequency Estimation Methods

2020 ◽  
Author(s):  
Daniel F. Friedemann ◽  
Daniel Motter
Keyword(s):  
High Frequency ◽  
Frequency Estimation ◽  
Frequency Measurement ◽  
Measurement Methods ◽  
Estimation Methods ◽  
Frequency Components

Frequency anti-islanding protections use frequency measures to determine an islanding condition, which are usually filtered to eliminate high frequency components. Digital relays can use different frequency estimation methods, which could lead to different results between different methods and filter lengths. This paper compares three frequency estimation methods found in digital relays against noise, harmonics, DC decays, steps and slopes of frequency, showing their intrinsic differences. Islanding events are simulated to show the importance of investigating frequency measurement methods and filter lengths before performing any protection study.

scholarly journals Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1823
Author(s):  
Xu-Bo Wang ◽  
Le-Ming He ◽  
You-Cao Ma ◽  
Wen-Juan Liu ◽  
Wei-Jiang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
3D Imaging ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Frequency Bandwidth ◽  
Half Wavelength ◽  
Acoustic Beams ◽  
Working Frequency ◽  
Sub Wavelength ◽  
2D Array

Piezoelectric micromachined ultrasonic transducers (PMUT) are promising elements to fabricate a two-dimensional (2D) array with a pitch small enough (approximately half wavelength) to form and receive arbitrary acoustic beams for medical imaging. However, PMUT arrays have so far failed to combine the wide, high-frequency bandwidth needed to achieve a high axial resolution. In this paper, a polydimethylsiloxane (PDMS) backing structure is introduced into the PMUTs to improve the device bandwidth while keeping a sub-wavelength (λ) pitch. We implement this backing on a 16 × 8 array with 75 µm pitch (3λ/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (−6 dB) and has little influence on the impulse response sensitivity. By widening the transducer bandwidth, this backing may enable using PMUT ultrasonic arrays for high-resolution 3D imaging.

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