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Title:	Design and development of wideband microstrip patch antennas for microwave sensors application
Authors:	Md. Naimur Rahman (P86256)
Supervisor:	Mohammad Tariqul Islam, Prof. Dr.
Keywords:	Microstrip antennas Microwave communication systems Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	16-Jul-2018
Description:	With the rapid advancement of microstrip technology, patch antennas are extensively used in various fields, such as agriculture, medical, sensor, and communications, etc. Dielectric-based microwave sensors are being used in different areas like moisture sensing, humidity sensing, pressure sensing, temperature sensing, medical imaging, salinity detection, sugar detection, and many more. Salinity detection is traditionally carried out by using conductivity-temperature-depth (CTD) and satellite measurements. The time consuming CTD needs great deal of human resources, whereas the satellite can’t measure salinity in small areas with accuracy. Again, the use of conductivity measurement with the aid of temperature sensor to detect salinity is complex and time consuming. Microwave sensors outperform the existing detection system as the patch antennas are low profile, light weight, and the detection system development cost is low. This thesis is dedicated to detecting salt and sugar content in water based on the dielectric properties of the solutions in terms of reflection coefficients using two microstrip patch antennas. The antenna performances were studied by the finite element method based High Frequency Structure Simulator (HFSS) and Finite Integrated Time (FIT) technique based electromagnetic simulator CST Microwave Studio software. Numerous parametric sweeps have been carried out to achieve wideband. The first antenna focuses on the ultra-wideband (UWB), where the wideband is achieved by sketching the broken heart shaped patch accompanied with slots in the partial ground plane achieving 46.38% more bandwidth. The second antenna deals with the enhancement of the bandwidth where 38.18% bandwidth is increased by cutting a hole from the circular shaped patch to make the crescent-shaped patch antenna. The broken heart shaped antenna achieves a bandwidth of 7.80 GHz (2.90 GHz to 10.70 GHz) with 3.33 dBi of average gain and 86.61% of average efficiency having stable radiation patterns. The crescent shaped antenna attains an impedance bandwidth of 15.50 GHz (2.50 GHz to 18.0 GHz) with over 75% of average efficiency and an average gain of 3.65 dBi retaining stable radiation patterns. In the salt and sugar content detection, the broken heart shaped antenna sensor detects the salt and sugar content in water at 3.50 GHz, 5.80 GHz, and 9.30 GHz, where in the free space, the reflection coefficients are -19 dB, -30 dB, and -19.5 dB, respectively. The crescent-shaped sensor detects the salt and sugar content in water at 3.20 GHz, 8.70 GHz, 11.60 GHz, and 14.50 GHz, where in the free space, the reflection coefficients are -21.40 dB, -21.60 dB, -23 dB, and -22.70 dB, respectively. The reflection coefficients gradually decrease with the increment of salt and sugar content in water. Both the wideband sensors show good sensitivity to detect salt and sugar content in water in terms of reflection coefficients. Having wider bandwidth with stable gain, efficiency, radiation patterns and good sensitivity to detect salt and sugar in water, the proposed wideband antennas are suitable for both the wireless communication applications as well as microwave sensor applications.,Master of Science
Pages:	111
Call Number:	TK7871.67.M5R335 2018 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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