• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.6
• /
• pp.958-964
• /
• 2001

In this paper, we propose a novel wide band printed monopole antenna called the staircase bow-tie monopole antenna (SBMA). We apply an extraordinary method for an impedance matching to conventional bow-tie monopoles. So we get the SBMA with a very wide band. Our antenna is smaller than a quarter wavelength in size but provides a 2:1 VSWR bandwidth of about 77.1 %. An antenna gain and a radiation pattern are about 1.7 dBi and omni-directional at 1.7 GHz, respectively.

• Journal of electromagnetic engineering and science
• /
• v.13 no.1
• /
• pp.22-27
• /
• 2013

This paper describes a wideband double dipole quasi-Yagi antenna fed by a microstrip-to-slotline transition. The transition feed consists of a microstrip radial stub and a slot radial stub, each with the same angle of $90^{\circ}$ but with different radii, to achieve wideband impedance matching. Double dipoles with different lengths are utilized as primary radiation elements to enhance bandwidth and achieve stable radiation patterns. The proposed antenna has a measured bandwidth of 3.34~8.72 GHz for a -10 dB reflection coefficient and a flat gain of $6.9{\pm}0.6$ dBi across the bandwidth.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.64 no.4
• /
• pp.207-211
• /
• 2015

In this paper, we proposed a broadband planar Yagi-Uda dipole antenna with dual tapered balance and unblance (balun) by CPW-fed to CPS. This antenna consisted of driver, three directors, dual tapered balun and CPS-fed to CPS. The fed structure of CPW-fed to CPS had a benefit points much simpler than other planar Yagi-Uda antennas and provided design more flexibility in arranging the reflector. The proposed antenna is introduced dual tapered balun to improve the impedance matching. It balun is inserted between the CPW-ground and the CPS. The proposed antenna is exhibited the bandwidth of 4.78 GHz (1.94~6.72 GHz) (S11 < -10 dB) and the gain of 4.9~7.2 dBi within that bandwidth. This antenna will applicate wireless communication.

• Transactions on Electrical and Electronic Materials
• /
• v.15 no.2
• /
• pp.55-59
• /
• 2014

An implantable CPW fed monopole antenna embedded into human tissue is proposed for ISM band biomedical applications. The proposed antenna is made compatible for implantation by embedding it in an alumina ceramic substrate (${\Box}_r=9.8$ and thickness=0.65 mm). The proposed antenna covers the ISM band of 2.45 GHz. The radiation parameters, such as return loss, E-Plane, H-Plane, are measured and analyzed, using the method of moments. The proposed antenna has substantial merits over other implanted antennas, like low profile, miniaturization, lower return loss, and better impedance matching and high gain.

• Proceedings of the KIEE Conference
• /
• 2008.05a
• /
• pp.151-152
• /
• 2008

In this paper, a dual band LNA (Low Noise Amplifier) with a matching circuit using varactor diode is designed for 912MHz and 2450MHz RFID system. The operating frequency is controlled by the bias voltage applied to the varactor diode. The measured results demonstrate that gain is 13.6dB and 6.8dB at 912MHz and 2450MHz. The measured NF (Noise Figure) is 1.4dB and 3.1dB at 912MHz and 2450MHz, respectively.

• Journal of information and communication convergence engineering
• /
• v.12 no.1
• /
• pp.1-7
• /
• 2014

A novel design of a simple circular ring with open-ended monopole antenna for wireless local area network (WLAN) applications is proposed in this article. The proposed antenna consists of an open-ended circular ring and $50-{\Omega}$ microstrip feed-line. The proposed antenna is capable of generating two separate resonant modes with good impedance-matching conditions. A prototype of the proposed antenna is designed, fabricated, and measured. Acceptable agreement between the measurement and simulation results is achieved. Experimental results show that the proposed antenna has operating bandwidths of 1.99-3.04 GHz and 5.08-6.1 GHz with a return loss of less than -10 dB, covering the required bandwidths of the 2.4/5.2/5.8-GHz WLAN standards. This is a microstrip antenna for IEEE 802.11a/b wireless local area networks applications. Meanwhile, the two-dimensional (2D) radiation patterns and three-dimensional (3D) gain performance of the antenna are also observed and discussed.

• Transactions on Electrical and Electronic Materials
• /
• v.16 no.5
• /
• pp.250-253
• /
• 2015

A novel implantable CPW fed Apollian shaped antenna embedded into human tissue is proposed for ISM band biomedical applications. The proposed antenna is made compatible for implantation by embedding it in an alumina ceramic substrate(ε_r=9.8 and thickness= 0.65 mm). The proposed antenna covers the ISM band of 2.45 GHz. The radiation parameters such as return loss, xy-plane, xz-plane, and yz-plane etc., are measured and analyzed using the agilent vector network analyzer. The proposed antenna has substantial advantages, including low profile, miniaturization ability, lower return loss, better impedance matching, and high gain over conventional implanted antennas.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1997.10a
• /
• pp.247-251
• /
• 1997

FCM(Fuzzy Cognitive Map) is a fuzzy signed directed graph for representing causal reasoning which has fuzziness between causal concepts. Authors have already proposed FCM-based fault diagnostic scheme and verified its usefulness. However, the previously proposed scheme has the problem of lower diagnostic resolution as in the case of other qualitative approaches. In order to improve the diagnostic resolution, a concept of fuzzy number is introduced into the basic FCM-based fault diagnostic algorithm. By incorporation the fuzzy number into fault FCM models, quantitative information such as the transfer gain between the state variables can be effectively utilized for better diagnostic resolution. Furthermore, an enhanced TAM(Temporal Associative Memory) recall procedure and modified and modified pattern matching scheme are also proposed.

• 한국정보통신설비학회:학술대회논문집
• /
• 2004.08a
• /
• pp.369-372
• /
• 2004

In this paper, a low noise amplifier (LNA) in receiver of Low Noise Block Down Converter (LNB) for direct broadcasting service (DBS) is implemented by using GaAs HEMT The LNA is designed for operation between 10.7GHz-12.7GHz. The LNA consists of input, output matching circuits, DC-blocks and RF-chokes. The result of simulation of the LNA shows that a noise figure is less than 1.4dB and a gain is gloater than 9.2dB in the bandwidth of 10.7 to 12.7GHz with good flatness of 0. ldB

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.2
• /
• pp.18-23
• /
• 1992

Recently, SSPAs(Solid-State Power Amplifiers) with high linearity and efficiency replace TWTAs (Traveling-Wave-Tube Amplifiers) in satellite transponders. In this paper, a power amplifier with maximum output power is designed and constructed using GaAs FET(MGF-1302) as a test model for the development of SSPAs. For conjugate matching of input and output network, transimission lines and stubs are optimized using microwave CAD program, LINMIC+. Power amplifier is realized on the teflon substrate($\in$S1rT=2.45) with a bandwidth of 1GHz at a center frequency of 8GHz. Maximum stable gain of simulation and simulation and experimental result is obtained 9.23, 7.65 dB, respectively.