Development of microgap and nanogap automated permittivity measurement system
The goal of this research is to develop an electronic system that integrated with nanogap capacitor biosensor. This system is called Permittivity Measurement System (PMS). It measures the impedance value of the nanogap capacitor and calculates the permittivity value based on the parameter specifi...
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| Format: | Thesis |
| Language: | English |
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| Online Access: | http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/21604/1/Full%20text.pdf http://dspace.unimap.edu.my:80/xmlui/bitstream/123456789/21604/2/p.%201-24.pdf |
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| Summary: | The goal of this research is to develop an electronic system that integrated
with nanogap capacitor biosensor. This system is called Permittivity Measurement
System (PMS). It measures the impedance value of the nanogap capacitor and
calculates the permittivity value based on the parameter specification of nanogap
capacitor obtained through characterization process. The parameters are gap
width, internal resistance, capacitance value with no sample, and cross section
area of the plate. One sample of nanogap and ten samples of microgap capacitor
are characterized. Five components combined to create PMS. The first component
is the sinusoidal wave generator and the technique that employed for sinusoidal
wave generation is the digital approximation sinusoidal wave generation
technique. The output frequency range is from 10Hz until 1kHz and the output
peak to peak voltage is 6V to -6V. The second component is the low pass filter.
This component is used for filtering the noise from sinusoidal wave. MAX262
programmable universal active filter is selected as the low pass filter. The third
component that creates PMS and has contact with the nanogap capacitor is the
impedance measurement unit. The auto balancing bridge method is employed to
measure the impedance value of the nanogap capacitor. A range circuit with eight
level of selection is added to wider the impedance measurement range. The
amplitude of the sinusoidal wave that applied to the nanogap capacitor is 200mV.
The fourth component is the phase differential measurement unit. It is responsible
to measure the phase difference between current and voltage wave. The fifth and
the main component of PMS is the XScale-Mini SBC. It is responsible to control,
capture, and analyze signal from the other component of PMS. Visual C++ is used
to develop the software part of XScale-Mini SBC. The current wave, voltage
wave, and also the output phase differential is captured and analyzed. All the
circuits are tested and the produced signals is shown and discussed. The test
shows that PMS is capable to measure up to 85% of accuracy. The simulation for
the electrical model of DNA during immobilization and hybridization is
performed. The fabricated circuit is tested through the measuring of micro and
nanogap capacitance. |
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