scholarly journals Microfluidic Biosensor Based on Microwave Substrate-Integrated Waveguide Cavity Resonator

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ahmed Salim ◽  
Sung-Hwan Kim ◽  
Joong Yull Park ◽  
Sungjoon Lim
Keyword(s):  
Resonance Frequency ◽  
Limit Of Detection ◽  
Cavity Resonator ◽  
Substrate Integrated Waveguide ◽  
Full Wave ◽  
Human Male ◽  
Microfluidic Biosensor ◽  
Phosphate Buffered Saline ◽  
Analytical Limit ◽  
Microwave Substrate

A microfluidic biosensor is proposed using a microwave substrate-integrated waveguide (SIW) cavity resonator. The main objectives of this noninvasive biosensor are to detect and analyze biomaterial using tiny liquid volumes (3 μL). The sensing mechanism of our proposed biosensor relies on the dielectric perturbation phenomenon of biomaterial under test, which causes a change in resonance frequency and return loss (amplitude). First, an SIW cavity is realized on a Rogers RT/Duroid 5870 substrate. Then, a microwell made from polydimethylsiloxane (PDMS) material is loaded on the SIW cavity to observe the perturbation phenomenon. The microwell is filled with phosphate-buffered saline (PBS) solution (reference biological medium). To demonstrate the sensing behavior, the fibroblast (FB) cells from the lungs of a human male subject are analyzed and one-port S-parameters are measured. The resonance frequency of the structure with FB cells is observed to be 13.48 GHz. The reproducibility and repeatability of our proposed biosensor are successfully demonstrated through full-wave simulations and measurements. The resonance frequency of the FB-loaded microwell showed a shift of 170 MHz and 20 MHz, when compared to those of empty and PBS-loaded microwells. Its analytical limit of detection is 213 cells/μL. Our proposed biosensor is noncontact and reliable. Furthermore, it is miniaturized, inexpensive, and fabricated using simple- and easy-design processes.

scholarly journals Dielectric-Filled Reentrant Cavity Resonator as a Low-Intensity Proton Beam Diagnostic

Instruments ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Sudharsan Srinivasan ◽  
Pierre-André Duperrex
Keyword(s):  
Resonance Frequency ◽  
Proton Beam ◽  
Second Harmonic ◽  
Cavity Resonator ◽  
Beam Current ◽  
Dielectric Thickness ◽  
Medical Treatment Facility ◽  
Beam Currents ◽  
Paul Scherrer ◽  
Non Destructive

Measurement of the proton beam current (0.1–40 nA) at the medical treatment facility PROSCAN at the Paul Scherrer Institut (PSI) is performed with ionization chambers. To mitigate the scattering issues and to preserve the quality of the beam delivered to the patients, a non-interceptive monitor based on the principle of a reentrant cavity resonator has been built. The resonator with a fundamental resonance frequency of 145.7 MHz was matched to the second harmonic of the pulse repetition rate (72.85 MHz) of the beam extracted from the cyclotron. This was realized with the help of ANSYS HFSS (High Frequency Structural Simulator) for network analysis. Both, the pickup position and dielectric thickness were optimized. The prototype was characterized with a stand-alone test bench. There is good agreement between the simulated and measured parameters. The observed deviation in the resonance frequency is attributed to the frequency dependent dielectric loss tangent. Hence, the dielectric had to be resized to tune the resonator to the design resonance frequency. The measured sensitivity performances were in agreement with the expectations. We conclude that the dielectric reentrant cavity resonator is a promising candidate for measuring low proton beam currents in a non-destructive manner.

scholarly journals Characteristics of VLF atmospherics near the resonance frequency of the Earth-ionosphere waveguide 1.6–2.3 kHz by observations in the auroral region

2010 ◽  
Vol 28 (1) ◽  
pp. 193-202 ◽  
Author(s):  
A. A. Ostapenko ◽  
E. E. Titova ◽  
A. P. Nickolaenko ◽  
T. Turunen ◽  
J. Manninen ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Spectral Maximum ◽  
Left Hand ◽  
Ionosphere Plasma ◽  
Full Wave ◽  
Transverse Resonance ◽  
The Earth ◽  
Polarized Waves ◽  
Small Absorption ◽  
The Right

Abstract. Recordings of ELF-VLF waves with the right-hand (RH) and the left-hand (LH) circular polarization were made in Northern Finland. Analysis showed a difference between the RH and LH polarized waves. A pronounced maximum of the wave amplitude was observed at the first critical frequency of the Earth-ionosphere waveguide (the first transverse resonance) around 1.6–2.3 kHz. The wave had the circular LH polarization at this maximum. To interpret observations, we computed the characteristics of the waveguide modes by using the full wave solution in the night model of the ionosphere. Computations show that the spectral maximum at the first transverse resonance frequency arises from a small absorption of the LH polarized radio wave in the magnetized ionosphere plasma, forming the upper boundary of the Earth-ionosphere waveguide.

Broadband Transition between Substrate Integrated Waveguide (SIW) and Rectangular Waveguide for Millimeter-Wave Applications

2011 ◽  
Vol 130-134 ◽  
pp. 1990-1993 ◽  
Author(s):  
Kuang Da Wang ◽  
Wei Hong ◽  
Ke Wu
Keyword(s):  
Millimeter Wave ◽  
Rectangular Waveguide ◽  
Return Loss ◽  
Substrate Integrated Waveguide ◽  
Full Wave ◽  
Vertical Transition ◽  
W Band ◽  
Relative Bandwidth ◽  
Is Design ◽  
Better Than

In this paper, a broadband and simple vertical transition between substrate integrated waveguide and standard air-filled rectangular waveguide is design and experimentally verified. From full-wave simulation of the structure, a relative bandwidth of 19.5% in W-band with return loss better than 20dB is reached. Then, five copies of back-to-back connected transitions are fabricated on RT/Duroid 5880 substrate. The experimental results show that the transition pairs have an average of 15% relative bandwidth with return loss better than 12dB and insert loss lower than 1.2dB. To explain the differences between simulated and tested results, an error analysis is presented.

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