Free-Space Microwave Characteristics of Natural Rubber Composites Filled With Carbon Black for Microwave Application

Ramli, Azlinda (2004) Free-Space Microwave Characteristics of Natural Rubber Composites Filled With Carbon Black for Microwave Application. Masters thesis, Universiti Putra Malaysia.

[img] PDF
1360Kb

Abstract

A contactless and non-destructive microwave method has been developed to characterize natural rubber composites from reflection and transmission measurements made at normal incidence. Microwave non-destructive testing (MNDT) using free-space microwave measurement (FSMM) system involves measurement of reflection and transmission coefficient in free-space. The measurement system consist of a pair of spot focusing horn lens antenna, mode transition, coaxial cables and vector network analyzers (VNA). The inaccuracies in free-space measurements are due to two main sources of errors. 1) Diffraction effects at the edges of the material specimen. 2) Multiple reflections between horn lens antennas and mode transitions via the surface of the sample. The spot-focusing antennas are used for minimizing diffraction effects and we have implemented free space TRL calibration technique by establishing three standards, namely, a through connection, a short circuit connected to each port and a transmission line connected between the test ports. This calibration along with time domain gating feature of the VNA can eliminate effects of multiple reflections.In this method, the free-space reflection and transmission coefficients, S1 and SZ1 are measured for natural rubber composites sandwiched between two Teflon plates of 10.64 mm thickness which act as a half-wave transformer at mid-band. The actual reflection and transmission coefficient, S1 1 and SZ1 of the natural rubber composites are then calculated from measured S1 1 and SZ1 by using ABCD matrix transformation in which the complex permittivity and thickness of the Teflon plates are known. From the complex permittivity, loss tangent, conductivity, wavelength, velocity and skin depth can be obtained. Result for natural rubber composites filled with different concentrations of carbon black are reported in frequency range 9-1 1 GHz.

Item Type:Thesis (Masters)
Subject:Rubber - Composite materials - Microwave measurements - Case studies
Subject:Microwaves
Chairman Supervisor:Associate Professor Mohd Adzir Mahdi, PhD
Call Number:FK 2004 102
Faculty or Institute:Faculty of Engineering
ID Code:5969
Deposited By: Nur Izyan Mohd Zaki
Deposited On:06 May 2010 09:12
Last Modified:27 May 2013 07:26

Repository Staff Only: Edit item detail


Universiti Putra Malaysia Institutional Repository

Universiti Putra Malaysia Institutional Repository is an on-line digital archive that serves as a central collection and storage of scientific information and research at the Universiti Putra Malaysia.

Currently, the collections deposited in the IR consists of Master and PhD theses, Master and PhD Project Report, Journal Articles, Journal Bulletins, Conference Papers, UPM News, Newspaper Cuttings, Patents and Inaugural Lectures.

As the policy of the university does not permit users to view thesis in full text, access is only given to the first 24 pages only.