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This work reports on the ability of ZnO nanostructures deposited using thermal chemical vapour deposition (TCVD) method as the sensing membrane for extendend-gate field effect transistor (EGFET) application. Four samples was prepared at different deposition time ranging from 500 to 650 °C in order to study the effect of deposition temperature on EGFET pH sensor performance. The surface morphology...
this paper presents the use of natural rubber as a substrate in the design of UHF RFID tag antenna. Prototype meander dipole antenna was simulated using CST Microwave Studio to operate at 921 MHz, using natural rubber as the substrate and copper as the conductor. The overall dimension of the tag is 63 × 63 × 1.3 mm3. Experimental studies on the effects of NR properties are done to facilitate efforts...
Carbon black is a type of filler used in natural rubber to improve their mechanical and electronic properties. Previously, a preliminary study on the effects of filler content on the performance of flexible antennas through computer simulations has been reported by our group. In this paper, we continue the work by offering experimental data to support the simulations so that comprehensive understanding...
This paper describes how the performance of rubber-based flexible antennas is affected under several bending conditions. Natural rubber is selected as the substrate due to its flexibility and robustness. The proposed antenna was designed and optimized to operate at 2.45 GHz. The antenna performance is observed in terms of variations of the resonance frequency and bandwidth due to the bending. Simulated...
This paper reports for the first time, the use of natural rubber as a substrate in the design of flexible antennas. Four inset fed patch antennas with different dimensions were simulated to resonate at 8 and 10 GHz. The rubber samples were prepared using two different amounts of carbon filler at 20 and 25 % to alter the dielectric properties. Investigations were done to understand the effects of natural...
The experimental results for high-frequency characteristics (from 2 to 20 GHz) of graphene films are presented. Samples with multi-layer graphene were fabricated and characterized from curve-fitting experimental results with values simulated using an electromagnetic simulator. From RF two-port network experiments, the circuit parameters of capacitance, resistance and inductance were extracted using...
This paper reports for the first time, the use of natural rubber as a substrate in the design of flexible antennas. Three inset feed patch antennas with different dimensions were simulated to resonate for 8 and 10 GHz. The rubber samples were prepared using two different amounts of carbon at 20 and 25 % to alter the dielectric properties. Investigations were done to understand the effects of natural...
In this paper, we compare several calibration methods available for on-wafer microwave measurements conducted on transmission lines made of graphene. Multi-layered graphene films were grown on Si wafers coated with SiO2 and Ni using chemical vapor deposition. In order to facilitate high frequency characterization, and to replicate their function as radio frequency integrated circuits (RFIC) interconnects,...
Fillers are used in natural rubber to improve their mechanical and electronic properties. This paper presents a study on the effects of filler on flexible antenna performance utilizing natural rubber as their substrate. CST Microwave Studio was used to simulate three antennas resonating at 2.45 GHz with different permittivity and loss tangent (tan δ). The dielectric properties of rubber were varied...
In this paper we report an investigation on the possibility of using graphene nano-ribbon (GNR) as a conductive material in MMIC applications in the range of 2–20 GHz. GNRs provide an advantage to the applications of MMIC transmission lines, as the line impedance can be controlled by their dimensions. The structural characteristics of graphene films grown on Ni film deposited on Si/SiO2 wafers after...
This paper describes the effects of bending on four different paper-based antennas — conventional patch antenna, antenna using rectangular EBG, circular EBG and wideband fractal monopole antenna. These antennas were designed with the aid of CST MICROWAVE Studio to operate at 10.15 GHz using photo paper as the substrate having relative permittivity, □r = 3.2. Since these antennas were designed using...
In this paper graphene nanoribbons (GNRs) are proposed as a new conductive material for monolithic microwave integrated circuit (MMIC) transmission lines to replace existing materials, because they have the potential to offer better performance. Multi-layered graphene films were grown on SiO2/ Si wafers coated with Ni using chemical vapour deposition. Co-planar GSG electrodes of various widths and...
In this paper, we report the first attempt to use natural rubber as a substrate in the design of flexible microstrip patch antennas. The effects of dielectric properties of rubber on the performance of microstrip patch antennas are presented. The patch geometry has been designed and optimized at a frequency of 10 GHz. It has been found that for a fixed substrate thickness, the antenna directivity...
The fabrication of single patch antenna for proposed Leucaena Leucocephala (“Petai Belalang”) Wood Plastic Composite (WPC) substrate board and FR4 substrate board is presented in this paper. The experiment objective was to measure the performance of an antenna fabricated on the proposed board by comparing the performance in term of Dielectric Constant value, Tangent Loss value, Return Loss, Radiation...
This paper presents the use of Chebychev transformer in the design of multi-layer microwave absorbers constructed of coconut shells. The two, three and four multi-layer absorbers were modelled based on measured permittivity. The permittivity were obtained using microwave non-destructive testing (MNDT) from previous experiment. Then the permittivity of each layer was calculated using Chebychev multi-section...
In this paper, the measurement of complex dielectric constant of natural rubber at microwave frequencies is reported. A free space, non-destructive technique was used to measure the parameter for several rubber samples at X band. The samples were prepared using different amounts of carbon filler to alter the dielectric properties so that the relation between filler content and εr can be investigated...
Principles to determine dielectric constant and loss tangent measurement using Agilent 85070E Dielectric Probe Kit 200 MHz to 50 GHztechnique is presented in this paper. The experiment objective was to measure the dielectric constant and loss tangent of Leucaena Leucocephala (Local Malaysian name Petai Belalang) material that laminated by Polypropylene Polymer. The Fabricated proposed boards were...
This paper presents a very selective wideband-bandpass filter topology, which is more compact, compared to a conventional coupled line filter and requires much lesser adjustment of parameters. The new topology consists of two identical one- wavelength rings that are combined with four identical quarter-wavelength coupled-lines, resulting in 7th order bandpass response. The use of the rings allows...
This paper proposed a dual-band ring filter using two identical microstrip dual-mode ring resonators. The rings are cascaded in series side-by-side via a single quarter wavelength coupled-line forming two transmission poles which are distributed in each passband. Meanwhile, the coupled-line positioned in between the two rings help to create the center transmission zero which can be used to control...
This paper presents a wideband bandpass filter topology which is based on a combination of a one-wavelength ring and two identical quarter-wavelength coupled-lines. The 3rd order bandpass response can be controlled by varying the line impedance of the ring and the even- and odd-mode impedances of the coupled lines. A simplified equivalent circuit diagram of the topology is also proposed to open for...
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