• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.800-806
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• 2008

In this paper, a wide-band dipole antenna suitable for use in PCS/WCDMA/WiBro($1.750{\sim}2.39\;GHz$) base station array antenna is presented. The presented antenna is a dipole antenna with pate which has the reflector element and improves the gain flatness. To confirm the wide-band characteristics and the gain flatness of the presented antenna, the experimental antenna is fabricated and its radiation characteristics are measured, compared with calculated results. It is shown that the designed antenna has VSWR less than 1.5, gain over 5 dBi, and gain flatness 0.74 dB in $1.75{\sim}2.39\;GHz$. The measured results show good agreement with the calculated results. From these results, we confirm that the designed antenna can be used as a array element of the wide-band base station array antenna for PCS/WCDMA/WiBro.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.232-237
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• 2024

In this paper, a broadband double dipole quasi-Yagi antenna using a 4×2 meander line array structure for maintaining 8 dBi gain was studied. The 4×2 meanderline array structure consists of a unit cell in the shape of a meanderline conductor, and it was placed above the second dipole antenna of the double dipole quasi-Yagi antenna. A double dipole quasi-Yagi antenna with generally used multiple strip directors was designed on an FR4 substrate with the same size, and the input reflection coefficient and gain characteristics were compared. Comparison results showed that the impedance frequency bandwidth increased by 6.3% compared to when using the multiple strip directors, the frequency bandwidth with a gain of 8 dBi or more increased by 10.1%, and average gain also slightly increased. The frequency band of the fabricated antenna for a voltage standing wave ratio less than 2 was 1.548-2.846 GHz(59.1%), and gain was measured to be more than 8 dBi in the 1.6-2.8 GHz band.

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.294-300
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• 2013

In this paper, we present performance analysis results of parametric array communication system in terms of theoretical BER and channel capacity of MIMO in underwater AWGN channel by using simplified SNR of difference frequency. The SNR of the difference frequency is calculated by using transmission loss, noise level, and source level of difference frequency in which nonlinear effect is considered. By assuming primary frequencies as 210 kHz and 190 kHz, difference frequency as 20 kHz, transducer diameter as 0.1 m, and noise level as 50 dB and the requested BER as $10^{-4}$, we obtain parametric array communication range gains over the communication system using primary frequency of 59.11 km in fresh water and 5 km in sea water, respectively. Also we obtain range gains of 38.84 km and 46.38 km in fresh water, and 3.88 km and 4.38 km in sea water when we use SISO and $2{\times}2$ MIMO parametric array communications for the channel capacity of 10 bps/Hz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1752-1757
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• 2011

In a traditional phased array radar, closely spaced antenna elements transmit a scaled version of single waveform to maximize the signal energy. On the contrary, a multiple-input multiple-output (MIMO) radar consists of widely separated antennas and transmits an arbitrary waveform from each antenna element. These waveforms and spatial diversity enable superior capabilities compared with phased array radar. At high signal-to-noise ratio (SNR), the detection performance of the MIMO radar is better than the phased array radar due to the diversity gains. However, the phased array radar outperforms the MIMO radar at low SNR, due to the energy maximization. In this paper, we investigate the compromised scheme between the MIMO radar and the phased array radar. Employing the MIMO radar equipped with phased array elements, the compromised scheme achieves both array gain and diversity gain. Also, we compare the performance degradation when the steering direction is incorrect.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1269-1274
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• 2019

The paper presents a design of simple four-element microstrip-patch array antenna that is suitable for 5G applications. The proposed array consists of four rectangular microstrip patch elements with semicircular etches made on both sides of each elements. The antenna is fed using the combination of series and corporate feeding networks. The size of the ground is also changed to improve the antenna frequency. Finally, yagi elements are also added to improve the directive gain of the antenna. The presented microstrip patch array is able to achieve wide frequency bandwidth of 21.95-31.86 GHz. The antenna has also attained gain of 9.7 dB at 28 GHz and has maintained high gain and high directivity throughout the frequency band. The proposed array antenna fed by series-corporate feeding network, with low profile and simple structure is a good candidate for 5G applications.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.130-133
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• 2010

본 논문에서는 X-band 절전센서용 마이크로스트립 구형패치 배열 안테나의 설계 방법을 제안 하고자 한다. 제안된 배열 안테나는 송 수신 안테나가 각각 1x2배열로 구성 되었다. 안테나는 CST MWS를 사용하여 시뮬레이션 하였고 FR-4 기판(h=1.0mm, ${\varepsilon}_r$=4.4)을 사용하여 제작하였다. 시뮬레이션 결과는 대역폭이 4%(VSWR${\leq}$2), 이득은 6.3dBi, 빔폭은 약 $60^{\circ}$(El)/$15^{\circ}$(Az)로 예측되었다. 안테나는 시뮬레이션 결과를 바탕으로 제작 되었고 절전센서용 RF 송수신기 회로 뒷면에 설치되어 무반사실에서 방사 특성을 측정하였다. 측정된 결과는 대역폭이 7%(VSWR${\leq}$2), 이득은 4.8dBi, 빔폭은 약 $55^{\circ}$(El)/$15^{\circ}$(Az)로 시뮬레이션 결과와 매우 유사한 결과를 얻었다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.285-289
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• 2002

In this paper, microstrip line-probe feeding patch array antenna with center frequency 5.8㎓ is designed and manufactured. The microstrip line - probe feeding structure has broadband characteristic and be able to modify the array structure for improving antenna gain. In this result, microstrip line-probe feeding patch array antenna has 17.6% bandwidth and 8㏈i antenna gain, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.853-859
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• 2007

This paper presents a microstrip patch array antenna having transmission feed and reception feed for satellite communication in the Ku band. In this paper, the element of the patch array antenna is a three-stacked structure consisting of one radiation patch and two parasitic patches for high gain and wide bandwidth characteristics. To obtain higher gain, the unit elements are expanded into a $1{\times}8$ may using a mixture of series and parallel feeds. The proposed antenna has horizontal polarization for the Rx band and vertical polarization for the Tx band. To verify the practicality of this antenna, we fabricated a three-stacked patch array antenna and measured its performance. The gain of the array antenna in the Rx and Tx bands exceeds 17 and 18 dBi, respectively. The impedance bandwidth is over 10 % in both bands. The cross-polarization level is below -25 dB, and the sidelobe level is below -9.4 dB.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.925-930
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• 2018

In this paper, we present a low profile dual-microstripline-fed double 4-arrayed meander monopole antenna with a cross-type element back by separated four-segments mesh-type reflector. The cross-type element and separated four-segments mesh-type reflector leads to enhance radiation patterns and antenna gain characteristics. The measurement value of the proposed antenna show that it has dipole-like radiation pattern characteristics. The experimental peak gain of fabricated antenna is about 2.89 dBi, which presents relatively high gain characteristics for a low profile(small-size) one. This antenna can be applied mobile RFID(radio frequency identification) readers, small medical instruments, broadcasting and home-networking operations, and other low profile high-gain systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.1
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• pp.115-121
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• 2012

In this paper, the design and fabrication of slot array in the broad wall of the waveguide for Ka-band monopulse radar are discussed. The aperture distributions are designed for the desired antenna gain, beamwidth and Side-lobe Level(SLL), and then slot parameters, such as lengths and offsets, are obtained for corresponding to each slot admittance in the equivalent circuit by using Elliot's array synthesis procedure. MWS-CST simulation shows the return loss below -10 dB, antenna gain above 32 dBi, 3 dB beamwidth of 3.7 degree and SLL of -20 dB. In order to demonstrate the expected results, the designed antenna is fabricated and measured.