• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.2-11
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• 2001

The L-shaped strip is shown to be an attractive feed for the thick mierostrip antenna (thickness around 10% of the operating wavelength). The L-strip incorporated with the radiating patch introduces a capacitance suppressing some of the inductance introduced by the strip itself. In this paper, a wideband microstrip patch antenna fed by L-strip for the PCS ($1,750{\sim}1,850MHz$) and IMT-2000 ($1,920{\sim}2,170MHz$) broad-band is presented. A two-element array fed by L-strip is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth is over 31% (VSWR < 1.5, 615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.11-19
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• 2010

In this paper, H-plane filtering-horn antenna operating at millimeter frequency band is proposed with embedded filter and three-layered dielectric lens for frequency selection and maintenance of main beam direction, respectively. The waveguide-typed filter and H-plane sectoral horn antenna are replaced with considerably size-reduced PCB substrate-typed filtering antenna using via fences and several posts. The waveguide-typed filter and H-plane sectoral horn antenna were designed in air-filled waveguide and then combined into size-reduced PCB substrate. For the control of the thickness of dielectric lens, single and multi dielectric lens have been employed. As a result of antenna gain, 8 and 13.5 dBi have been obtained at 41.5 GHz, respectively, from the simulations of single and multi-lens antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.12 s.91
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• pp.1131-1140
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• 2004

In this paper, we proposed a flate-plate antenna employing semi-annular slots for satellite broadcast reception. The radiating element of the antenna is dual annular slots fed by a strip dipole, which have a wider bandwidth than the rectangular slot. A $16{\times}16$ array antenna is designed using stripline T-junction power dividers. Measurements of the fabricated antenna show a gain of 28.0$\~$29.5 dB in 11.7$\~$12.8 GHz frequency range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.827-836
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• 2001

The L-shaped strip is shown to be an attractive feed for the thick microstrip antenna (thickness around 10% of the operating wavelength). The L-strip incorporated with the radiating patch introduces a capacitance suppressing some of the inductance introduced by the strip itself. In this paper, a wideband microstrip patch antenna fed by L-strip for the PCS (1,750~1,850 MHz) and IMT-2000 (1,920~2,170 MHz) broad-band is presented. A two-element array fed by L-strip is also proposed. Both the antennas have stable radiation patterns across the passband. The impedance bandwidth is over 31% (VSWR < 1.5, 615 MHz) of the center frequency. Moreover, both the antennas have about 7 dBi average gain.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.1
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• pp.34-41
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• 2010

In this paper, we analyze and simulate co-channel interference (CCI) mitigation method for cooperative communication systems employing decode-and-forward relays. In co-channel interference mitigation method, A source transmits signals that are encoded by orthogonal code. Then, the receiver can distinguish its own signals form the received signals by using the orthogonal code which is already known to the receiver. The orthogonal codes applied to this paper are orthogonal Gold codes. However, we can employ other codes, which have orthogonality, as the orthogonal code. In addition, we utilize a space time block coding (STBC) scheme for enhancing the system performance by obtaining additional array gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.709-715
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• 2002

In this paper, a novel low profile dual feeding microstrip antennas with microstrip and H-shaped aperture feeding are proposed to achieve high isolation and easy feeding, and the validity of the proposed antennas is demonstrated experimentally. In the proposed single and 1$\times$4 array antenna, the measured isolations are less than -49 dB and -48 dB, impedance bandwidths are 4 % at 12.5 GHz and 2.1 % at 14.25 GHz for the VSWR<1.5 in both antennas and maximum gains are 8.25 dBi and 14.2 dBi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1467-1474
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• 2010

A tile type active T/R(Transmit/Receive) module for X-band active array radar is demonstrated in this paper. Proposed tile type structure based on fuzz button solderless vertical interconnection shows wide band characteristic of about 30 % bandwidth in X-band with insertion loss of below 0.6 dB and input and output VSWR of less than 1.7. Moreover, the mismatching generally appeared in the vertical interconnection which shown wide band characteristic can also be minimized and, therefore, good gain flatness can be achieved.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.61-64
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• 2017

A phase shifter is one of the key components that change the phase of an individual antenna in millimeter-wave phased array system. This paper presents a low-loss phase shifter design with two parallel 2-state amplifiers. To get the same gain of $0^{\circ}/180^{\circ}$ each state, delay lines are in the middle of each stage of the 2-Stage amplifiers. Normally, when adding AMPs in parallel, a power combiner/divider such as Wilkinson Power Combiner/Divider is added, but they are directly connected because it can cause added losses in silicon wafer. The measured data shows 12dB gain and 174-degree phase difference at 5GHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.811-816
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• 2011

In this paper, we propose a optimal design using the Evolution Strategy of a high gain $4\times4$ array antenna that have the resonant frequency of a 19.05GHz with 18.86GHz~19.26GHz bandwidth. The proposed array antenna structure is designed to be allocated equally electric power by microstrip patch power splitter. Thus the optimal array antenna with power splitter are determined by using an optimal design program based on the evolution strategy. To achieve this, an interface program between a commercial EM analysis tool and the optimal design program is constructed for implementing the evolution strategy technique that seeks a global optimum of the objective function through the iterative design process consisting of variation and reproduction. The simulation result of $4\times4$ array antenna is confirmed that the Gain is 19.36 dBi at resonance frequency 19.05GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.956-966
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• 1997

Dynamic free-space optical interconnection system is experimented by a holographic crossbar with single-state switching architecture. For dynamic operation, electrically addressed liquid-crystal spatial light modulator and diffraction gratings are used in place of passive holograms of matrix-matrix crossbar. Diffraction gratings are consisted of regular cells which have different phase delays. This pixelated phase grating array displayed on SLM(Spatial Light modulator) deflects an input beam toward a wanted direction or splits an input beam into many beams and then steers them to desired positions. Through the experimental results, free-space optical interconnection is dynamically perfomed using a computer, SLM and phase diffraction gratings.