• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.7B
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• pp.875-879
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• 2001

마이크로스트립 패치안테나의 대역을 증가시키는 방법이 꾸준히 연구되고 있다. 본 연구에서는 구형 패치 구조에 기생 소자를 더한 형태로 구형 패치 외부에 바(bar)와 밴드(band) 모양의 기생소자를 설치하여 프린징 효과를 최소화 하고자 하였으며, 이로 인한 안테나 효율의 향상과 대역폭을 증가를 시키고자 하였으며, 또한 기생소자의 폭과 방사안테나의 간격을 조절하여 대역폭과 임피던스정합 특성의 변화를 해석하였다. 이를 이용하여 LMDS통신 주파수 대역인 24.6GHz∼28.5GHz에서 공진 대역을 갖도록 설계하였다. 정재파비 2.0 이하를 기준으로 기존의 패치안테나의 중심주파수에 대한 대역 이용율이 수 %인데 반하여, 본 연구에서 제시한 밴드를 설치한 구조의 경우 12.92%로 증가함을 알 수 있고, 또한 본 연구에서 제시한 외부 밴드를 갖는 구조가 급전선로와 패치 안테나와의 정합특성이 월등함을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1940-1945
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• 2006

The small and wideband annular ring slot antenna with eccentric radiating structure and low impedance feedline is presented. This antenna is analyzed by using substrate with permittivity 4.3 and thickness 1mm. As the measured impedance bandwidth of proposed antenna is $118%(S_{11}{\leq}-10dB)$, its bandwidth is much broader than that of conventional annular ring slot antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1327-1336
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• 2012

In this paper, the dual-faced monopole antenna, which is arranged by numerous rectangular ring patches in sequence for the multi-bands is proposed. The ring type structure of the patch can be increased the bandwidth. Therefore the bandwidth and beam width are improved by using multiple arrayed patches. When the ring type patches are inserted serially, the resonance frequencies are occurred by the current flow from the first ring patch. It is possible because the gap between the patches is very narrow. In addition, if the patches are composed on the same plane as the feed-line, fabrication could be very difficult because the gap between the patches is extremely narrow. The thickness and permittivity of the antenna, moreover, are very important parameters because both sides of the substrate are used. We finally found the optimal thickness and permittivity to generate the coupling effect by simulation. All patches are consisted of 4-steps which the patch size was decreased 85 % by each step. In conclusion, the resonant frequency bands are 1.75~2.6 GHz(850 MHz), 3.24~3.46 GHz(220 MHz), 3.8~4.0 GHz(200 MHz), and 4.4~4.9 GHz(500 MHz).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.1
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• pp.13-21
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• 1997

In this paper, the oscillator type active antenna used as an element of active phased array antenna is designed and fabricated using slot coupling. The radiating element and active circuit are fabricated on each layer respectively and coupled electromagnetically through slot on the ground plane. This structure can solve the problems such as narrow bandwidth of microstrip antenna, spurious radiation by active circuits, and spaces for integration of the feeding circuits which are caused by integrating antennas with oscillator circuits in the same layer. The active antenna in this paper, the oscillation frequency can be tuned linearly by controlling the drain bias voltage of FET. The frequency tuning range is between 12.37 GHz to 12.65 GHz when bias voltage is varied from 3V to 9V, thus frequency tuning bandwidth is 280 MHz (2.24%). The output power of antenna is uniform within 5dB over frequency tuning range. Therefore this active antenna can be used as an element of linear or planar active phased array antennas.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.2
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• pp.83-90
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• 2000

In this paper, a stacked circular-disk microstrip 1${\times}$4 array antenna was designed and manufactured and tested to apply in next generation mobile communication, on IMT-2000 system(up-link: 1.885 GHz∼2.025 GHz, down-link: 2.11 GHz∼2.2 GHz) base station which has dual frequency, broadband and high-gain characteristics. The experimental results are as follows : resonant frequency of 1.885 GHz and 2.178 GHz VSWR (1.064 , 1.432), return loss (-30.19 dB , -24.99 dB), band width (VSWR<2) are 402 MHz, -3dB beam width at radiation pattern are ${\alpha}$E-16.8$^{\circ}$, ${\alpha}$H-69$^{\circ}$(1.885 GHz) and ${\alpha}$E-l5.2$^{\circ}$, ${\alpha}$H-51.5$^{\circ}$(2.178 GHz), gain(13.7 dBi∼15.21 dBi).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.5
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• pp.559-569
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• 2012

In this paper, the X($1{\times}2$, 10.525 GHz) and K($3{\times}6$, 24.15 GHz) bands patch array antenna having single feed line for radar detector applications is proposed. The left side of the proposed array antenna is X band array antenna and the right is K band array antenna. Two array antennas with two stubs located in the front of antennas are fed through one transmission line. If the array antennas which have the different resonance frequency are fed by one transmission line using general T-junction, it interferes each other and the array antenna lost its character. Therefore, to prevent these interferences, two stubs using open and short property of stub are designed. First of all, the performances of array antenna weren't changed when each array antennas were connected with the stub and in the end, it is found out that it was the same when the two array antennas were combined and feed through the one transmission line. The measured gain at X band is 6.47 dBi and measured gain at K band is 13.07 dBi. The experimental results agree well with the simulated ones.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.491-503
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• 2014

In this paper, a $TM_{31}$ higher order mode half circular-ring microstrip antenna with monopole-like radiation characteristic for on-body communication is proposed. By using shorting vias, $TM_{31}$ resonance mode was excited, while achieving compact low-profile antenna with monopole-like radiation characteristics. To overcome the narrow bandwidth of a patch antenna, a C-shape half ring patch with shorting vias having $TM_{31}$ mode is closely located around a half circular patch. For size reduction, half mode is adopted. The proposed antenna has the overall dimensions of $0.25{\lambda}_0{\times}0.46{\lambda}_0{\times}0.025{\lambda}_0$ at the industrial, scientific, and medical(ISM) 2.45 GHz band(2.4~2.485 GHz) and the 10-dB return loss is 4.24 % ranging from 2.38 to 2.49 GHz. To verify body effect, two-thirds muscle equivalent semi solid phantom was fabricated and used to measure the antenna performance. A communication link is analysed to investigate the effect of human-body movements and antenna locations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.348-351
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• 2013

Recently, a brain imaging system with microwave devices has been proposed. The brain imaging system requires a small antenna which has ultra wide band(UWB) operating frequency bandwidth(0.5~2 GHz) and non-varying boresight of antenna over the frequency band. This paper proposes asymmetric corrugations on a tapered slot antenna (TSA) so that the size of the TSA is reduced by 14 % while 10 dB return loss bandwidth is satisfied over the operating frequency band from 0.5 GHz to 2 GHz. A miniaturized TSA with symmetric corrugations shows tilted boresight whilst frequency is getting lower; however, the proposed TSA with asymmetric corrugations maintains direction of boresight for different frequencies. This enhancements make an asymmetric corrugated TSA meet the requirement of the brain imaing system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.36-46
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• 2013

This paper proposes the design of broadband spiral antenna for a potable non-linear junction detector (NLJD) system. To realize the broadband antenna design, it was considered optimization of the number of spiral turns by iteration calculation. Ground plane with the Archimedean spiral slit to keep the same current distribution between radiating plane and ground is considered for circular polarization design. In order to realize high directivity and high gain of the proposed antenna, the cavity wall and the metal cap which is located on back of ground plane were also considered in design. Measurement results of return loss were agreed well with VSWR 2:1 at interested frequency band among 2.4 to 2.44 GHz, 4.84 to 4.92 GHz and 7.28 to 7.36 GHz. Measured axial ratio was observed 3 dB below and showed reasonable agreement with simulation results. Characteristics of the RHCP(Right Hand Circular Polarization) with the measured gain of 6.8 dBi above at interested frequency band were also observed.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.24-32
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• 2003