scholarly journals Planar Offset Short Applicable to the Calibration of a Free-Space Material Measurement System in W-Band

2021 ◽  
Vol 21 (1) ◽  
pp. 51-59
Author(s):  
Jin-Seob Kang ◽  
Jeong-Hwan Kim
Keyword(s):  
Electrical Properties ◽  
Measurement System ◽  
Free Space ◽  
Physical Contact ◽  
Frequency Range ◽  
Electromagnetic Devices ◽  
W Band ◽  
Measurement Results ◽  
Properties Of Materials ◽  
Space Material

The electrical properties of materials and their dependence on frequency and temperature are indispensable in designing electromagnetic devices and systems in various areas of engineering and science for both basic and applied researches. A free-space transmission/reflection method measuring the free-space scattering parameters of a material under test (MUT) located at the middle of transmit/receive antennas in a free space is suitable for non-destructively testing the MUT without prior machining or physical contact in high-frequency range. This paper describes a planar offset short applicable to the calibration of a quasi-optic based free-space material measurement system in the millimeter-wave frequency range. The measurement results of the dimensional and electrical properties for the three fabricated planar offset shorts with the phase difference of 120° between the reflection coefficients of the planar shorts in the W-band (75–110 GHz) are presented.

scholarly journals Modelling of electrical properties of mn-zn ferrites taking into account the frequency of the occurrence of the dimensional resonance

2018 ◽  
Vol 69 (3) ◽  
pp. 219-225 ◽  
Author(s):  
Teodora Plamenova Todorova ◽  
Vencislav Cekov Valchev ◽  
Alex Van den Bossche
Keyword(s):  
Electrical Properties ◽  
Measurement Data ◽  
Frequency Range ◽  
Data Set ◽  
Measurement Results ◽  
Electro Magnetic ◽  
Circuit Modelling ◽  
Magnetic Nature ◽  
Frequency Dependences ◽  
Dimensional Resonance

Abstract Besides their magnetic properties, Mn-Zn ferrites are also characterized by appreciable electrical properties. This electro- magnetic nature of Mn-Zn ferrites material properties causes a dimensional resonance to occur in samples. The latter hinders measurements of the frequency dependences of intrinsic permittivity and electrical conductivity. In the paper, we present a sign in measurement results that shows the frequency range in which dimensional resonance has already occurred. Above this range, properties extracted from measurements are not intrinsic any longer. We refer to the sign to determine the last point of the measurement data set that is used as an input for an equivalent circuit modelling of the electrical properties. This “last point” criterion helps to exclude the possibility of modelling apparent properties instead of intrinsic ones. The results obtained show that the frequency dependent electrical properties may be well modeled even if the upper limit of the input frequency range to the curve fitting is below the frequency range in which the dimensional resonance occurs.

scholarly journals Investigation on Symmetric and Asymmetric Broadband Low-Loss W-Band Pillbox Windows

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2060
Author(s):  
Tongbin Yang ◽  
Xiaotong Guan ◽  
Wenjie Fu ◽  
Dun Lu ◽  
Chaoyang Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Wide Band ◽  
Simulation Software ◽  
Experimental Results ◽  
Frequency Range ◽  
Low Loss ◽  
W Band ◽  
Measurement Results ◽  
Vacuum Electronic Devices ◽  
Wave Region

In order to develop wide-band low-loss windows for W-band vacuum electronic devices and easily fabricate them, symmetric and asymmetric pillbox windows are investigated and reported in this paper. A symmetric pillbox window and an asymmetric pillow-box window were designed, simulation optimized, fabricated, and tested. The initial parameters for the two pillbox windows were designed by equivalent circuit theory. Computer simulation technology (CST) three-dimensional (3D) electromagnetic simulation software was used to verify and optimize the design. Because of the uncontrollability of welding during the experiment, this article provides two solutions. One is to measure and reprocess the symmetrical pillbox window with the dielectric sheet welded to reduce the influence of welding on the measurement results; the other is an asymmetrical box window which is designed to avoid the error caused by the welding of the box window. The best experimental results for the symmetric pillbox window were |S21| close to 1 dB and reflection parameter |S11| close to 10 dB in the frequency range of 77–110 GHz. The experimental results for the asymmetric pillbox window were |S21| < 1 dB nearly in the frequency range of 76–109.5 GHz. The experimental results show that both solutions efficiently complete the design of broadband pillbox windows and would potentially be operated in the gigahertz millimeter-wave region.

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