• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.4
• /
• pp.386-392
• /
• 2002

This paper presents a basic characteristics of 4-element circular array dipole antennas for 4-sector beam steering. The coupled integral equations for the unknown current distributions on dipole elements are derived and solved by applying Galerkin's method of moments. The parasitic elements have been used to increase the directional gain and the beam is steered electronically either by sswitching between the parasitic elements or switching the position of the active element. The parasitic elements are switched short-circuited or open-circuited as required to steer a directional beam. In order to verify the theoretical analysis, the radiation pattern was compared with experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.2
• /
• pp.202-208
• /
• 2003

In this paper, we proposed a microstrip patch array antenna for DBS reception which had high gain and high tilted angle through mutual coupling driver patch to parasitic patch in H-plane edge and broadside direction in different layers. It was designed and fabricated in 16$\times$8 array by using low cost polyester based copper-clad laminate and foam instead of high cost dielectric substrate. It had gain of 22.9 dBi, beamwidth of 4.6$^{\circ}$, and tilted angle from broadside direction of 43.9$^{\circ}$.

• Parasites, Hosts and Diseases
• /
• v.44 no.3
• /
• pp.251-254
• /
• 2006

Monoclonal antibody (mAb) Tg786 against Toxoplasma gondii has been found to detect a 42-kDa rhoptry protein (ROP6) which showed protease activity and host cell binding characteristics after secretion. Using the mAb, a colony containing a 3'-UTR was probed in a T. gondii cDNA expression library. A full length cDNA sequence of the rhoptry protein was completed after 5'-RACE, which consisted of 1,908 bp with a 1,443 bp ORF. The deduced amino acid sequence of ROP6 consisted of a polypeptide of 480 amino acids without significant homology to any other known proteins. This sequence contains an amino terminal stop transfer sequence downstream of a short neutral sequence, hydrophilic middle sequence, and hydrophobic carboxy terminus. It is suggested that the ROP6 is inserted into the rhoptry membrane with both N- and C-termini.

• ETRI Journal
• /
• v.34 no.5
• /
• pp.674-683
• /
• 2012

We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular-ring-shaped tuning stub that can be deployed in ultra-wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band-notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L- and J-shaped parasitic elements. The antenna characteristics can be modified to tune the band-notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L- and J-shaped parasitic elements also provide the band-rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.1
• /
• pp.54-62
• /
• 2015

This paper describes the design and fabrication of an electronically rotated Tactical Air Navigation(TACAN) antenna using parasitic elements and PIN diode switches. We used parasitic elements arranged in a circular array and PIN diode switches to electronically rotate the antenna instead of employing a mechanically rotated antenna using motor. The antenna's physical characteristics and design features to generate the cardioid pattern and nine-lobe pattern including bearing information are described and simulated. The measured result shows a very good agreement with simulation and meets the specification of MIL-STD-291C.

• ETRI Journal
• /
• v.39 no.5
• /
• pp.746-755
• /
• 2017

In this paper, an electrostatic discharge (ESD) protection circuit is designed for use as a 12 V power clamp by using a parasitic-diode-triggered silicon controlled rectifier. The breakdown voltage and trigger voltage ($V_t$) of the proposed ESD protection circuit are improved by varying the length between the n-well and the p-well, and by adding $n^+/p^+$ floating regions. Moreover, the holding voltage ($V_h$) is improved by using segmented technology. The proposed circuit was fabricated using a $0.18-{\mu}m$ bipolar-CMOS-DMOS process with a width of $100{\mu}m$. The electrical characteristics and robustness of the proposed ESD circuit were analyzed using transmission line pulse measurements and an ESD pulse generator. The electrical characteristics of the proposed circuit were also analyzed at high temperature (300 K to 500 K) to verify thermal performance. After optimization, the $V_t$ of the proposed circuit increased from 14 V to 27.8 V, and $V_h$ increased from 5.3 V to 13.6 V. The proposed circuit exhibited good robustness characteristics, enduring human-body-model surges at 7.4 kV and machine-model surges at 450 V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.3
• /
• pp.32-43
• /
• 2014

This paper presents the intra capacitance modeling according to the winding method, section bobbin and coil structure for hybrid choke coil capable of the EMI attenuation of broad bands from lower frequency bands to higher frequency bands and high frequency type common-mode choke coil capable of the EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. In case of high frequency type CM choke coil, it can be explained the parasitic capacitance of A type and section bobbin type winding methods among them is much smaller than the other. The first resonant frequency of the proposed CM choke coil tends to increase as the parasitic capacitance becomes small and its impedance characteristics also show improved performance as the first resonant frequency increases. In case of hybrid choke coil using rectangular copper wire, it has investigated its parasitic capacitance compared to CM choke coil of conventional toroidal type becomes small. Also it has confirmed through the experiment results that CE margin and RE margin in frequency bands 0.5MHz to 5MHz and 30MHz to 200MHz are respectively 10dB and 15dB greater than that of conventional type in case of one stage EMI filter structure adopting hybrid choke coil compared to two stage EMI Filter structure using two of each CM choke coil used in the lower and higher frequency bands or two of CM choke coil used in only the lower frequency bands. In the future, the hybrid choke coil and CM choke coil of high frequency type show it can be practically used in not only LED/LCD-TV SMPS but also several applications such as LED Lighting, Laptop Adapter, Server Power Supply and so on.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.12
• /
• pp.1059-1068
• /
• 2016

This paper proposes slow wave structure(SWS) utilized to increase antenna gain of printed dipole antenna(PDA) and to suppress sidelobe level simultaneously, and makes sure of electrical characteristics of the antenna according to parameter variations of components of the slow wave structure. The printed slow wave structure which is composed of a dielectric substrate and a metal rods array is located on excited direction of the PDA, affecting the radiation pattern and its intensity. Parasitic elements of the metal rods are arrayed in narrow consistent gap and have a tendency to gradually decrease in length. In this paper, array interval, element length, and taper angle are selected as the parameter of the parasitic element that effects radiation characteristics. Magnitude and phase distribution of the electrical field are observed and analyzed for each parameter variations. On the basis of these results, while the radiation pattern is analyzed, array methods of parasitic elements of the SWS for high gain characteristics are provided. The proposed antenna is designed to be operated at the Wifi band(5.15~5.85 GHz), and parameters of the parasitic element are optimized to maximize antenna gain and suppress sidelobe. Simulated and measured results of the fabricated antenna show that it has wide bandwidth, high efficiency, high gain, and low sidelobe level.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.7
• /
• pp.719-725
• /
• 2008

In this paper, we have proposed a printed monopole antenna using parasitic elements. The broadband characteristics of the antenna is obtained by using the printed monopole and parasitic elements. To confirm the broadband characteristics of the antenna, of have designed and fabricated the proposed antenna. The return loss and radiation patterns are measured in the frequency range of$0.8{\sim}1.2\;GHz$. The measured results show that the proposed antenna has return loss less than -10 dB in the operating frequency band and the radiation pattern is the dipole-like patterns. The antenna gain varies from 1.7 to 4.6 dBi in the operating frequency band. Thus, the proposed antenna can be used for the broadband repeater antenna $0.806{\sim}0.960\;GHz$(TRS-800, CDMA and GSM-900).

• Journal of Advanced Navigation Technology
• /
• v.15 no.4
• /
• pp.596-601
• /
• 2011

This paper has presented research results for the switching mode class E frequency multiplier that has simple circuit structure and high efficiency. Frequency multiplication is coming from the nonlinearity of the active component, and this paper models the FET active component as a simple switch and some parasitics to analyze the characteristics. The matching component parameters for the class E frequency doubler have been derived with modeling the FET as a input controlled switch and some parasitics. A circuit simulator, ADS, is used to simulate the output voltage and current waveform and efficiency with the variation of the parasitic values. With 2.9GHz input and 2V bias, the drain efficiency has been decreased from 98% to 28% with changing the parasitic capacitance from 0pF to 1pF at 5.8GHz output, which shows that the parasitic capacitance CP has the most significant effect on the efficiency among the parasitics of FET.