Novel 4 loops coupler in microwave cavity measurement of permittivity

Author(s):  
Hai Zhang ◽  
Baoqing Zeng ◽  
Lei Ao ◽  
Nannan Li ◽  
Yong Fang ◽  
...  
1978 ◽  
Vol 56 (8) ◽  
pp. 1037-1045 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
M. Wong

Microwave cavity measurements have been extended to the 140 GHz or 4.6 cm−1 region. The details of the apparatus and method are presented. The techniques have been applied to the measurement of collision-induced absorption in N2 and CO2 at 295 K. The results are compared with measurements at lower microwave frequencies and also with far infrared measurements.


1988 ◽  
Vol 24 (17) ◽  
pp. 1085 ◽  
Author(s):  
W.J. Radcliffe ◽  
J.C. Gallop ◽  
C.D. Langham ◽  
M. Gee ◽  
M. Stewart

2021 ◽  
Vol 92 (3) ◽  
pp. 033305
Author(s):  
Maria Simanovskaia ◽  
Alex Droster ◽  
Heather Jackson ◽  
Isabella Urdinaran ◽  
Karl van Bibber

2009 ◽  
Vol 1222 ◽  
Author(s):  
Pengzhao Gao ◽  
Evgeny V. Rebrov ◽  
Jaap C. Schouten ◽  
Richard Kleismit ◽  
John Cetnar ◽  
...  

AbstractNanocrystalline Ni0.5Zn0.5Fe2O4 thin films have been synthesized with various grain sizes by sol–gel method on polycrystalline silicon substrates. The morphology and microwave absorption properties of the films calcined in the 673–1073 K range were studied by using XRD, AFM, near–field evanescent microwave microscopy, coplanar waveguide and direct microwave heating measurements. All films were uniform without microcracks. The increase of the calcination temperature from 873 to 1073 K and time from 1 to 3h resulted in an increase of the grain size from 12 to 27 nm. The complex permittivity of the Ni-Zn ferrite films was measured in the frequency range of 2–15 GHz. The heating behavior was studied in a multimode microwave cavity at 2.4 GHz. The highest microwave heating rate in the temperature range of 315–355 K was observed in the film close to the critical grain size of 21 nm in diameter marked by the transition from single– to multi–domain structure of nanocrystals in Ni0.5Zn0.5Fe2O4 film and by a maximum in its coercivity.


2018 ◽  
Vol 2018 ◽  
pp. 1-24 ◽  
Author(s):  
Zhijun Zhang ◽  
Tianyi Su ◽  
Shiwei Zhang

Aiming at improving the food quality during microwave process, this article mainly focused on the numerical simulation of shape effect, which was evaluated by microwave power absorption capability and temperature distribution uniformity in a single sample heated in a domestic microwave oven. This article only took the electromagnetic field and heat conduction in solid into consideration. The Maxwell equations were used to calculate the distribution of microwave electromagnetic field distribution in the microwave cavity and samples; then the electromagnetic energy was coupled as the heat source in the heat conduction process in samples. Quantitatively, the power absorption capability and temperature distribution uniformity were, respectively, described by power absorption efficiency (PAE) and the statistical variation of coefficient (COV). In addition, we defined the comprehensive evaluation coefficient (CEC) to describe the usability of a specific sample. In accordance with volume or the wave numbers and penetration numbers in the radial and axial directions of samples, they can be classified into different groups. And according to the PAE, COV, and CEC value and the specific need of microwave process, an optimal sample shape and orientation could be decided.


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