Free-space millimeter-wave measurement of the complex dielectric constant of radome materials using nonlinear least-squares analysis

2003 ◽  
Author(s):  
B.R. Rao
Keyword(s):  
Dielectric Constant ◽  
Least Squares ◽  
Millimeter Wave ◽  
Free Space ◽  
Nonlinear Least Squares ◽  
Complex Dielectric Constant ◽  
Wave Measurement

MEASUREMENT OF THE COMPLEX DIELECTRIC CONSTANT OF LIQUIDS AT CENTIMETER AND MILLIMETER WAVELENGTHS

1957 ◽  
Vol 35 (9) ◽  
pp. 995-1003 ◽  
Author(s):  
A. G. Mungall ◽  
John Hart
Keyword(s):  
Dielectric Constant ◽  
Methyl Alcohol ◽  
Free Space ◽  
Normal Incidence ◽  
Complex Dielectric Constant ◽  
Families Of Curves ◽  
Millimeter Wavelengths ◽  
Centimeter Wave ◽  
Space Technique ◽  
Wave Region

The measurement of the complex dielectric constant of lossy liquids in the millimeter and centimeter wave region by a free-space technique is described. The method involves the measurement of absorption per wavelength and of reflectance at normal incidence. Families of curves are given for the relations between these two quantities and the real and imaginary parts of the complex dielectric constant. Results for ethyl and methyl alcohol at 9 and 13 mm. wavelength are compared with those obtained by waveguide techniques.

scholarly journals Millimeter-Wave Dielectric-Constant Measurement of Alumina by Free-Space Time-Domain Method.

2002 ◽  
Vol 49 (10) ◽  
pp. 895-899
Author(s):  
Saburo Sano ◽  
Akihiro Tsuzuki ◽  
Akihiro Gotou ◽  
Takashi Yoshioka ◽  
Yukio Makino ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Millimeter Wave ◽  
Time Domain ◽  
Free Space ◽  
Space Time ◽  
Time Domain Method ◽  
Domain Method ◽  
Constant Measurement ◽  
Dielectric Constant Measurement

Millimeter-wave measurements of the complex dielectric constant of an advanced thick film UV photoresist

1998 ◽  
Vol 27 (6) ◽  
pp. L40-L42 ◽  
Author(s):  
C. E. Collins ◽  
R. E. Miles ◽  
R. D. Pollard ◽  
D. P. Steenson ◽  
J. W. Digby ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Thick Film ◽  
Millimeter Wave ◽  
Complex Dielectric Constant ◽  
Wave Measurements ◽  
Millimeter Wave Measurements

Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi
Keyword(s):  
Dielectric Constant ◽  
Portland Cement ◽  
Electromagnetic Waves ◽  
Low Cost ◽  
Complex Dielectric Constant ◽  
Life Cycle Costs ◽  
Parallel Plates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Set Up

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.

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