scholarly journals Two Alternative Methods to Measure the Radiated Emission in a Reverberation Chamber

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Qian Xu ◽  
Yi Huang ◽  
Sheng Yuan ◽  
Lei Xing ◽  
Zhihao Tian
Keyword(s):  
Conventional Method ◽  
Signal Generator ◽  
Power Measurement ◽  
Alternative Methods ◽  
Network Analyzer ◽  
Reverberation Chamber ◽  
Enhanced Backscattering ◽  
Radiated Power ◽  
The One ◽  
Good Agreement

One of the most important applications of a reverberation chamber is for radiated power measurement. Two new alternative methods are proposed to measure the radiated power of equipment under test in a reverberation chamber in this paper. Traditionally, as stated in IEC 61000-4-21 standard, this measurement requires two antennas, a signal generator and a spectrum analyzer or receiver. However, it is found that if a signal generator is not available, a vector network analyzer can be used to complete the measurement. Furthermore, if only one antenna is available, by taking advantage of the enhanced backscattering effect, the measurement can still be completed. By incorporating the one- and/or two-antenna methods, the radiation efficiency of antennas is also considered. Measurements have been conducted to verify the proposed methods, the results from these three methods are compared, and a very good agreement is obtained. It is found that the two proposed methods are simpler than the conventional method.

Methods of Using a Vibratory System to Measure Small Rates of Turn

1969 ◽  
Vol 11 (5) ◽  
pp. 526-533 ◽  
Author(s):  
J. A. Linnett
Keyword(s):  
Angular Velocity ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Exciting Force ◽  
Velocity Curve ◽  
Alternative Methods ◽  
Vibratory System ◽  
Mass System ◽  
The One ◽  
Good Agreement

The equations of motion for a vibratory two-degrees-of-freedom spring mass system subjected to rotation about an axis perpendicular to its plane of vibration are considered, taking into account the various couplings that may be present. The rate of turn can be measured by three alternative methods, two of which involve an exciting force in the sensing direction in addition to the one vibrating the system. The shape of the phase angle against angular velocity curve is shown to be independent of damping, enabling the transient performance to be improved without affecting the sensitivity of the device. Experimental work shows good agreement with the developed theory.

scholarly journals Total Radiated Power Measurement in an Uncalibrated Reverberation Chamber

2019 ◽  
Vol 69 (5) ◽  
pp. 427-430
Author(s):  
Deepshikha Gururani ◽  
Harish S. Rawat ◽  
Satya K. Dubey ◽  
V.N. Ojha
Keyword(s):  
Quality Factor ◽  
Time Domain ◽  
Indoor Environment ◽  
Real Life ◽  
Power Measurement ◽  
Shielding Effectiveness ◽  
Reverberation Chamber ◽  
Radiated Power ◽  
Reverberation Chambers ◽  
The Time Domain

With the increased use of wireless communication in recent years, the use of reverberation chamber (RC) has increased to a great extent. Reverberation chambers have been eminently used for EMC testing and shielding effectiveness. The environment it provides is very similar to the reverberant surroundings that antenna undergoes in real life use. An experiment to measure total radiated power of antenna, antenna efficiency and quality factor of chamber in indoor environment is proposed. This will make the measurement very simple and inexpensive as designing and calibration of chamber will not be needed. In this paper, we have used three different techniques to compare total radiated power, quality factor, Rician K factor and efficiency of a patch antenna measured in indoor environment with RC data. The three method used include plate stirring method and two time domain methods. The time domain methods use modulated pulse and Gaussian pulse respectively for the measurement. The antenna and chamber parameters are measured in the real time and the data matched well with the RC data for different techniques.

scholarly journals Propagation Measurements at 2.4 GHz Inside a University Building and Estimation of Saleh- Valenzuela Parameters

2007 ◽  
Vol 3 (2) ◽  
pp. 99 ◽  
Author(s):  
Zoran Blažević ◽  
Igor Zanchi ◽  
Ivan Marinović
Keyword(s):  
Indoor Environment ◽  
Spatial Information ◽  
Delay Spread ◽  
Original Form ◽  
Density Functions ◽  
Network Analyzer ◽  
Channel Parameters ◽  
The One ◽  
Propagation Scenario ◽  
Good Agreement

In this paper we analyze measurements conducted in an indoor environment of our university building at a centralfrequency of 2.4 GHz in terms of the Saleh-Valenzuela channel. The channel parameters are extrapolated by processing the power-delay profiles measured by a vector network analyzer. Final adjustments of the parameters are obtained by comparison of simulated and measured delay-spread cumulative density functions, where a quite good agreement between the two is obtained. The predictions of the coherence bandwidth are satisfactory as well. We also considered some extensions to the original form of the model and concluded that the one that would be worthy to apply is the one that, besides temporal, incorporates also spatial information about the channel, whereas other modifications are found to be unnecessary or even unjustified for evaluation of this indoor propagation scenario.

Theoretical study of ground radiation tag antenna with Tunable open-slot exciter

2016 ◽  
Vol 9 (4) ◽  
pp. 945-952 ◽  
Author(s):  
Yi-Fang Lin ◽  
Ming-Jui Chang ◽  
Hua-Ming Chen ◽  
Shih-Ting Huang
Keyword(s):  
Radio Frequency ◽  
Radio Frequency Identification ◽  
Ground Plane ◽  
Measurement Data ◽  
Power Measurement ◽  
Radiated Power ◽  
Quarter Wavelength ◽  
Frequency Identification ◽  
Good Agreement ◽  
Inductive Reactance

A novel radio frequency identification tag antenna is composed of a resonant open-slot exciter and a dipole-type ground radiator. For a conjugate match to the Alien Higgs-4 chip impedance of 8−j149 Ω at 925 MHz, a quarter wavelength open-slot resonator embedded at the center of the dipole-type ground plane (130 × 18 mm2) was investigated and fabricated. Simple size adjustments and various loaded inductor of the open-slot resonator allow for easy control of the tag antenna resistance and inductive reactance, from which the chip impedance requirement can be easily obtained. The read range of the prototype antenna attached on a foam in the free space can reach more than 9 m, which has been tested for a radio frequency identification reader with 4.0-W of effective isotropic radiated power. Measurement data are in good agreement with simulation results.

scholarly journals Pressure-dependent calibration of the OH and HO<sub>2</sub> channels of a FAGE HO<sub>x</sub> instrument using the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC)

2015 ◽  
Vol 8 (2) ◽  
pp. 523-540 ◽  
Author(s):  
F. A. F. Winiberg ◽  
S. C. Smith ◽  
I. Bejan ◽  
C. A. Brumby ◽  
T. Ingham ◽  
...  
Keyword(s):  
Conventional Method ◽  
Atmospheric Chemistry ◽  
Field Measurements ◽  
External Pressure ◽  
Alternative Methods ◽  
Flow Tube ◽  
Temporal Decay ◽  
Calibration Methods ◽  
Conventional Alternative ◽  
Good Agreement

Abstract. The calibration of field instruments used to measure concentrations of OH and HO2 worldwide has traditionally relied on a single method utilising the photolysis of water vapour in air in a flow tube at atmospheric pressure. Here the calibration of two FAGE (fluorescence assay by gaseous expansion) apparatuses designed for HOx (OH and HO2) measurements have been investigated as a function of external pressure using two different laser systems. The conventional method of generating known concentrations of HOx from H2O vapour photolysis in a turbulent flow tube impinging just outside the FAGE sample inlet has been used to study instrument sensitivity as a function of internal fluorescence cell pressure (1.8–3.8 mbar). An increase in the calibration constants CHO and CHO2 with pressure was observed, and an empirical linear regression of the data was used to describe the trends, with ΔCHO = (17 ± 11) % and ΔCHO2 = (31.6 ± 4.4)% increase per millibar air (uncertainties quoted to 2σ). Presented here are the first direct measurements of the FAGE calibration constants as a function of external pressure (440–1000 mbar) in a controlled environment using the University of Leeds HIRAC chamber (Highly Instrumented Reactor for Atmospheric Chemistry). Two methods were used: the temporal decay of hydrocarbons for calibration of OH, and the kinetics of the second-order recombination of HO2 for HO2 calibrations. Over comparable conditions for the FAGE cell, the two alternative methods are in good agreement with the conventional method, with the average ratio of calibration factors (conventional : alternative) across the entire pressure range, COH(conv)/COH(alt) = 1.19 ± 0.26 and CHO2(conv)/CHO2(alt) = 0.96 ± 0.18 (2σ). These alternative calibration methods currently have comparable systematic uncertainties to the conventional method: ~ 28% and ~ 41% for the alternative OH and HO2 calibration methods respectively compared to 35% for the H2O vapour photolysis method; ways in which these can be reduced in the future are discussed. The good agreement between the very different methods of calibration leads to increased confidence in HOx field measurements and particularly in aircraft-based HOx measurements, where there are substantial variations in external pressure, and assumptions are made regarding loss rates on inlets as a function of pressure.

scholarly journals Pressure dependent calibration of the OH and HO<sub>x</sub> channels of a FAGE HO<sub>x</sub> instrument using the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC)

2014 ◽  
Vol 7 (7) ◽  
pp. 7963-8011 ◽  
Author(s):  
F. A. F. Winiberg ◽  
S. C. Smith ◽  
I. Bejan ◽  
C. A. Brumby ◽  
T. Ingham ◽  
...  
Keyword(s):  
Conventional Method ◽  
Atmospheric Chemistry ◽  
Field Measurements ◽  
External Pressure ◽  
Alternative Methods ◽  
Temporal Decay ◽  
Calibration Methods ◽  
Laser Systems ◽  
Conventional Alternative ◽  
Good Agreement

Abstract. The calibration of field instruments used to measure concentrations of OH and HO2 worldwide have traditionally relied on a single method utilising the photolysis of water vapour in air in a flow tube at atmospheric pressure. Here the calibration of two FAGE (Fluorescence Assay by Gaseous Expansion) apparatuses designed for HOx (OH and HO2) measurements have been investigated as a function of external pressure and temperature, using two different laser systems. The conventional method of generating known concentrations of HOx from H2O vapour photolysis in a turbulent flowtube impinging just outside the FAGE sample inlet has been used to study instrument sensitivity as a function of internal fluorescence cell pressure (1.8–3.8 mbar). An increase in the calibration constants COH and CHO2 with pressure was observed and an empirical linear regression of the data was used to describe the trends, with ΔCOH = (17 ± 11)% and ΔCHO2 = (31.6 ± 4.4)% increase per mbar air (uncertainties quoted to 2σ). Presented here are the first direct measurements of the FAGE calibration constants as a function of external pressure (440–1000 mbar) in a controlled environment using the University of Leeds HIRAC chamber (Highly Instrumented Reactor for Atmospheric Chemistry). Two methods were used: the temporal decay of hydrocarbons for calibration of OH, and the kinetics of the second-order recombination of HO2 for HO2 calibrations. Over comparable conditions for the FAGE cell, the two alternative methods are in good agreement with the conventional method, with the average ratio of calibration factors (conventional : alternative) across the entire pressure range COH(conv)/COH(alt) = 1.19 ± 0.26 and CHO2(conv)/CHO2(alt) = 0.96 ± 0.18 (2σ). These alternative calibration methods currently have comparable systematic uncertainties than the conventional method: ~28% and ~41% for the alternative OH and HO2 calibration methods respectively compared to 35% for the H2O vapour photolysis method; ways in which these can be reduced in the future are discussed. The good agreement between the very different methods of calibration leads to increased confidence in HOx field measurements and particularly in aircraft based HOx measurements, where there are substantial variations in external pressure, and assumptions are made regarding loss rates on inlets as a function of pressure.

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

scholarly journals Minkowski box from Yangian bootstrap

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Luke Corcoran ◽  
Florian Loebbert ◽  
Julian Miczajka ◽  
Matthias Staudacher
Keyword(s):  
Minkowski Space ◽  
Wigner Function ◽  
Functional Form ◽  
A Priori ◽  
Alternative Methods ◽  
Feynman Integrals ◽  
The One

Abstract We extend the recently developed Yangian bootstrap for Feynman integrals to Minkowski space, focusing on the case of the one-loop box integral. The space of Yangian invariants is spanned by the Bloch-Wigner function and its discontinuities. Using only input from symmetries, we constrain the functional form of the box integral in all 64 kinematic regions up to twelve (out of a priori 256) undetermined constants. These need to be fixed by other means. We do this explicitly, employing two alternative methods. This results in a novel compact formula for the box integral valid in all kinematic regions of Minkowski space.

scholarly journals Estimation of the Noise Source Level of a Commercial Ship Using On-Board Pressure Sensors

2021 ◽  
Vol 11 (3) ◽  
pp. 1243
Author(s):  
Hongseok Jeong ◽  
Jeung-Hoon Lee ◽  
Yong-Hyun Kim ◽  
Hanshin Seol
Keyword(s):  
Noise Source ◽  
Pressure Sensors ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Source Strength ◽  
Recording Time ◽  
Source Level ◽  
The One ◽  
Hydrophone Array ◽  
Good Agreement

The dominant underwater noise source of a ship is known to be propeller cavitation. Recently, attempts have been made to quantify the source strength using on-board pressure sensors near the propeller, as this has advantages over conventional noise measurement. In this study, a beamforming method was used to estimate the source strength of a cavitating propeller. The method was validated against a model-scale measurement in a cavitation tunnel, which showed good agreement between the measured and estimated source levels. The method was also applied to a full-scale measurement, in which the source level was measured using an external hydrophone array. The estimated source level using the hull pressure sensors showed good agreement with the measured one above 400 Hz, which shows potential for noise monitoring using on-board sensors. A parametric study was carried out to check the practicality of the method. From the results, it was shown that a sufficient recording time is required to obtain a consistent level at high frequencies. Changing the frequency resolution had little effect on the result, as long as enough data were provided for the one-third octave band conversion. The number of sensors affected the mid- to low-frequency data.

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