• Journal of Internet Computing and Services
• /
• v.21 no.2
• /
• pp.19-26
• /
• 2020

This paper analyses the feasibility of using implantable antennas to detect and monitor tumors. We analyze this setting according to the wireless propagation loss and signal fading produced by human bodies and their environment in an indoor scenario. The study is based on the ITU-R propagation recommendations and prediction models for the planning of indoor radio communication systems and radio local area networks in the frequency range of 300 MHz to 100 GHz. We conduct primary estimations on 915 MHz and 2.4 GHz operating frequencies. The path loss presented in most short-range wireless implant devices does not take into account the human body as a channel itself, which causes additional losses to wireless designs. In this paper, we examine the propagation through the human body, including losses taken from bones, muscles, fat, and clothes, which results in a more accurate characterization and estimation of the channel. The results obtained from our simulation indicates a variation of the return loss of the spiral antenna when a tumor is located near the implant. This knowledge can be applied in medical detection, and monitoring of early tumors, by analyzing the electromagnetic field behavior of the implant. The tumor was modeled under CST Microwave Studio, using Wisconsin Diagnosis Breast Cancer Dataset. Features like the radius, texture, perimeter, area, and smoothness of the tumor are included along with their label data to determine whether the external shape has malignant or benign physiognomies. An explanation of the feasibility of the system deployment and technical recommendations to avoid interference is also described.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.247.1-247.1
• /
• 2014

The capacitive coupled plasma is used widely in the semiconductor industries. Especially, the uniformity of the industrial plasma is heavily related with defect ratio of devices. Therefore, the industries need the capacitive coupled plasma source which can generate the uniform plasma and control the plasma's uniformity. To achieving the uniformity of the large area plasma, we designed multi-powered electrodes. We controlled the uniformity by controlling the power of each electrode. After this work, we started to research another concept of the plasma device. We make the plasma chamber that has multi-ground electrodes imaginary (CST microwave studio) and simulate the electric field. The shape of the multi-ground electrodes is ring type, and it is same as the shape of the multi-power electrodes that we researched before. The diameter of the side electrode's edge is 300mm. We assumed that the plasma uniformity is related with the impedance of ground electrodes. Therefore we simulated the imaginary chamber in three cases. First, we connected L (inductor) and C (capacitor) at the center of multi-ground electrodes. Second, we changed electric conductivity of multi-ground electrode. Third, we changed the insulator's thickness between the center ground electrode and the side ground electrode. The driving frequency is 2, 13.56 and 100 MHz. We switched our multi-powered electrode system to multi-ground electrode system. After switching, we measured the plasma uniformity after installing a variable vacuum capacitor at the ground line. We investigate the effect of ground electrodes' impedance to plasma uniformity.

• Journal of Korea Society of Industrial Information Systems
• /
• v.11 no.5
• /
• pp.98-104
• /
• 2006

In this parer, proposed a Miniature inverted F Antenna for Bluetooth applications using folded structure and confirm it through producing and measurement. The proposed antenna as PIFA is optimized the impedance matching and the radiation pattern by positioning of feed line and short line. This antenna is designed with Microwave Studio presented CST and the optimized antenna structure is fabricated. The optimized miniature antenna size is 17.3 * 6 * 0.8 mm, the measured return loss bandwidth is 220MHz at 2.45GHz, the radiation pattern is quasi omni, and the gain is -1 dBi. these results are similar to the simulation data. It is comparatively appropriate for Bluetooth system.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.30-30
• /
• 2011

The wave-cutoff tool is a new diagnostic method to measure electron density and electron temperature. Most of the plasma diagnostic tools have the disadvantage that their application to processing plasma where toxic and reactive gases are used gives rise to many problems such as contamination, perturbation, precision of measurement, and so on. We can minimize these problems by using the wave-cutoff method. Here, we will present the results obtained through the development of the wave-cutoff diagnostic method. The frequency spectrum characteristics of the wave-cutoff probe will be obtained experimentally and analyzed through the microwave field simulation by using the CST-MW studio simulator. The plasma parameters are measured with the wave-cutoff method in various discharge conditions and its results will be compared with the results of Langmuir probe. Another disadvantage is that other diagnostic methods spend a long time (~ a few seconds) to measure plasma parameters. In this presentation, a fast measurement method will be also introduced. The wave-cutoff probe system consists of two antennas and a network analyzer. The network analyzer provides the transmission spectrum and the reflection spectrum by frequency sweeping. The plasma parameters such as electron density and electron temperature are obtained through these spectra. The frequency sweeping time, the time resolution of the wave-cutoff method, is about 1 second. A short pulse with a broad band spectrum of a few GHz is used with an oscilloscope to acquire the spectra data in a short time. The data acquisition time can be reduced with this method. Here, the plasma parameter measurement methods, Langmuir probe, pulsed wave-cutoff method and frequency sweeping wave-cutoff method, are compared. The measurement results are well matched. The real time resolution is less than 1 ?sec. The pulsed wave-cutoff technique is found to be very useful in the transient plasmas such as pulsed plasma and tokamak edge plasma.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.8
• /
• pp.758-764
• /
• 2015

This paper describes the pattern synthesis of array antenna which conforms to a metallic curved surface formed by the rotation of a quadratic function by using EAGA(Enhanced Adaptive Genetic Algorithm). Three rotated-type conformal surfaces are realized by changing the coefficient of the quadratic function and the pattern of each conformal array antenna is synthesized. In order to reduce the overall time of pattern synthesis, the transformed active element pattern obtained by the active element pattern of the 2-dimensional planar array using Euler angles rotation is utilized instead of the active element pattern of the 3-dimensional conformal array antenna itself. To verify validity of the proposed synthesis procedure, the synthesized patterns using EAGA are compared with those obtained by MWS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.2
• /
• pp.164-171
• /
• 2014

Transmit(Tx)/Receive(Rx) dual band operation microstrip array for X-band satellite communications are designed, fabricated, and measured in this paper. The microstrip array antenna has Right Handed Circular Polarization(RHCP) for Tx band and Left Hand Circular Polarization(LHCP) for Rx band. Two stacked patches are used for wideband characteristics and corner-truncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, $2{\times}2$ sequential rotation array are applied. From the measured result, $8{\times}12$ microstrip array antennas have a good agreement with those of the simulation. Therefore the array antennas are applicable to military satellite communication antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.12
• /
• pp.1031-1043
• /
• 2015

This paper describes the pattern synthesis method of two kinds of conformal array antenna using the Enhanced Adaptive Genetic Algorithm (EAGA). One is the $1{\times}16$ conformal array antenna on a curved cylindrical metallic surface with quadratic function, and the other is the 18-element conformal arrary antenna on a metallic surface obtained by the rotation of a quadratic function curve around the axis. The active element pattern is utilized in the pattern synthesis. Especially for the case of the rotated-type conformal array antenna the transformed active element pattern obtained from the Euler's angle rotation of the active element pattern of the planar concentric array is utilized, which reduces the synthesis time a lot. To verify the validity of the proposed synthesis method the MATLAB results are compared with the MWS results. Furthermore, for the case of $1{\times}16$ conformal array antenna the measured results are compared with the MATLAB synthesized results.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.7 s.349
• /
• pp.156-161
• /
• 2006

In this paper, an E-patch antenna on the U-shaped ground plane is designed and experimental studied. In order to reduce to cross-polarization level and to enhance the gain of the microstrip patch antenna, a U-shaped ground plane is employed in the microstrip patch antenna. As a main radiator, an E-shaped patch is used to reduce the antenna size as small as possible. Also to enhance the bandwidth of the antenna, a substrate of the lowest permittivity of which thickness as thick as possible is used and a rectangular patch is overlaid on the air substrate of the E-shaped patch antenna. The radiation characteristics of the antenna are calculated by CST Microwave Studio 5.0 simulation software. Experimental results show that by increasing the height of the sidewall of the ground plane, the antenna gain is increased and the cross-polarization level is decreased.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.3
• /
• pp.318-325
• /
• 2019

As satellite communication technology with high efficiency and spatiality evolves, demands of customer for efficient and effective satellite broadcasting services are increasing due to interval reduction of the between satellites, and the limited radio-frequency spectrum resources. Recently, research on antenna that it possible to simultaneously receive multiple signal from various satellites while holding maintain the same number of previous reception channels by using the single reflector has been ongoing. It is necessary to be able to simultaneously receive signals from various satellites in order to maintain the same number of previous reception channels. We suggest a multiband antenna which can be simultaneously and independently receiving Ku band and Ka band satellite broadcasting signals transmitted by three adjacent satellites. We have designed and simulated using commercial design tools TICRA CHAMP and CST MWS to meet the target specifications. It appears that the antenna has -10 dB return loss, and more than 40 dBi directivity gain in Ku band and Ka band respectively.

• Composites Research
• /
• v.19 no.3
• /
• pp.1-6
• /
• 2006

As the structures of the high performance electronic equipments and devices recently become more complex, the electromagnetic interference (EMI) and compatibility (EMC) have been very essential for commercial and military purposes. Thus, sensitive electrical devices and densely packed systems need to be protected from electromagnetic wave. In this research, glass fabric/epoxy composites containing conductive multi-walled carbon nanotube (MWNT) and carbon fiber/epoxy composites as electrical shielding materials were fabricated and electrical properties of the composites were measured. The concerning frequency band is from 300 MHz to 1 GHz. The performances of composite shielding enclosures were predicted using electromagnetic wave 3-D simulation tool, CST Microwave Studio. The shielding enclosure made of carbon fiber/epoxy composites were fabricated and the shielding effectiveness (SE) was measured in the anechoic chamber.