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Corrosion behavior of structural carbon steels grade SS400 coated with copper and zinc exposed to soil sample extracted from the central part of Thailand is studied using weight loss analyses and electrochemical methods, including open circuit potential monitoring for 3600 seconds, electrochemical impedance spectroscopic analyses and potentiodynamic polarization measurements. Bare carbon steels are...
This paper presents the design of low-cost planar near-field to far-field measurement system for a small antenna and small scattering objects. This work is proposed to accurately and precisely measure the electromagnetic (EM) wave scattered from a small object. The minimum scanning resolution of the proposed system is 0.5 cm per step in horizontal and vertical directions. In order to design the proposed...
A design of planar rectangular spiral antennas for the wireless vehicle battery charging system operating at 13.56 MHz is presented in this paper. The proposed antennas are designed with low-cost, low-complexity and low-profile constraints. The study is performed by analyzing the power transmission efficiency of the spiral antennas via scattering parameters and associated reflection coefficients....
Uniform Geometrical Theory of Diffraction (UTD) ray solutions are developed for describing the radiation and mutual coupling that is associated with antennas on smooth convex metallic surfaces with a thin material coating. These solutions are based in turn on the generalization, via the principle of high frequency localization, of the canonical solutions obtained for corresponding cylinder and sphere...
This paper presents an accuracy of a modified UTD solution for a convex impedance cylinder based on the general 3D UTD solution for a smooth convex perfectly electric conductor (PEC) scattering problem. By employing the impedance boundary condition (IBC), the modified UTD solution for a convex impedance cylinder can be used for the material-coated PEC cylinder problem. Thus, the modified UTD solution...
This paper proposes the design of a thin-strip on-glass antenna for a DAB automotive application. The proposed antenna uses a triangular thin-strip monopole as a radiating element, including a ground strip matching technique to obtain an improved impedance matching. The antenna radiation pattern, reflection coefficient [∣S11∣ (dB)], polarization, and absolute gain in the operating frequency band are...
This paper presents a modified uniform theory of diffraction (UTD) solution in 3D case for computing the electromagnetic (EM) field scattering from the impedance cylinder surface. The proposed solution based on the general 3D UTD solution for a smooth convex perfect electric conductor (PEC) scattering problem. Here, the Pekeris-integral function in the 3D UTD PEC solution is modified by using the...
The radio wave propagation model is theoretically proposed in this paper, by using the uniform geometrical theory of diffraction (UTD) together with the Gaussian beam (GB) via the complex source point (CSP) technique. The path loss and multipath propagation are predicted in a Thai commercial orchard. The durian orchard is primarily chosen to be an example for this study but the radio wave propagation...
This paper presents a dual frequency band circularly polarized antenna system for Satellite Digital Audio Radio Service (SDARS) and Global Positioning System (GPS) applications. The proposed dual band antenna system consists of two circular patches each having four perpendicular slots for operating in two different frequency bands with left-handed circular polarization (LHCP) for SDARS and a right-handed...
An analysis of the path loss in the durian orchard is presented by using the complex source point technique (CSP) and the uniform geometrical theory of diffraction (UTD). The 2D Gaussian beams (GBs) expansion scattered by 2D cylindrical structures are presented. The GB can be generated by using the CSP. The GBs expansion can provides an efficient way of the synthesis of the radiation pattern of the...
This paper proposes an antenna using an eight-branch folded strip with a circular parasitic patch on circular ground plane for SDARS applications. The proposed antenna is designed to cover the bandwidth of 2.332-2.345 GHz (SDARS frequency band). The simulation simulation results of the proposed antenna are well-suited for XM Radio SDARS specification. The conical-beam pattern with left-handed circular...
The analysis of path loss in scattering zone by using UTD is presented. The results of the total field results from the UTD solution agree very well with that from NEC-BSC. Around the vicinity of the source, the UTD results agree with experimental results but not in the further region. This is due to the fact that the line-of-sight and reflected field components are very strong in this region. For...
The path loss measurements and modeling in durian orchard for wireless network at 5.8 GHz are presented. The path loss model is important to predict and design the wireless communication system in the durian orchard. The transmitter is set up near the bole of a durian tree and received the signal strength by spectrum analyzer. The communication channel is connected between the communication nodes...
This paper presents the path loss model and measurement of wireless network in durian garden at 5.8 GHz. This study is important in wireless communication system for predication and design the communication system of durian garden such as communication range, power transfer, position of transmitting and receiving antenna. From the results, it is obvious that the path loss at the distance of 128 m...
The statistical characteristic measurement results of wireless sensor network in durian orchard at 5.8 GHz are presented. The measurement results are performed to study the channel characteristic of the radio wave propagation in the durian orchard. The communication channel is connected from sensor node to communication node and between communication node. The transmitter is setup at the bole of a...
The two-rectangular-printed-spiral antenna with U-strip is proposed. The increasing electrical length and impedance matching is performed by using two spiral arms and adding U-strip. There is no ground plane for this antenna structure. The size is relatively small. The measured return loss is -12.435 dB at 433 MHz with 5.455 % bandwidth (428-452 MHz). The measured absolute gain is about -5 dBi. The...
This paper proposes the compact antenna for server node of wireless sensor network system. The antenna parameters are varied to achieve the nearest horizontally polarized omnidirectional pattern. The overall antenna width, length and height are fixed for suitable installation. The antenna structure is simple and its design is straightforward. The return loss, radiation pattern, absolute gain and cross-polarization...
This paper presents the characteristics of a microwave band pass filter using microstrip semi-circular patch resonators. Design method is based on coupling coefficients of inter-coupled resonator and the external quality factors of the input and output resonators. To improve the filter characteristics by using coupling structure, the microstrip semi-circular patch resonators are used instead of the...
The short-range and near ground measurements of signal attenuation in the UHF band are performed to study radio wave propagation in a car park for a wireless sensor network application. The measurement setup is based on the radio wave propagation along the row of a parking lot (full of cars) by varying heights of server antenna. In the application, a small antenna and a compact antenna are employed...
In this paper, a circular vertical patch antenna excited by probe with cross-strip above cylindrical reflector is proposed. The proposed antenna is used at base station for point-to-point communication in wireless local area network systems (WLAN). The antenna is analyzed by CST (Microwave Studio) program. The measured results of the prototype antenna operating at 2.45 GHz yields an impedance bandwidth...
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