• Journal of the Korea Society of Computer and Information
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• v.19 no.4
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• pp.71-79
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• 2014

This paper investigates wideband dual-polarized microstrip antenna with H-shaped coupling slot. These types of antennas are used to prevent deterioration of transmission quality caused by terminal interference or multipath fading, which usually occur when many terminals are used in limited space such as hot-spot zones. The experimental results show that the impedance bandwidth ($SWR{\leq}2$) of 33.98% and the peak gain of 8.58 dBi (at 2.11 GHz) were obtained by the frequency band under 2.7 GHz. The proposed antenna is designed originally for multiple service bands with simple structure and easily be mass-produced for various commercial applications.

• Journal of Advanced Navigation Technology
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• v.21 no.2
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• pp.193-199
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• 2017

In the paper, a dual band-notched monopole antenna is proposed for 2.4 GHz WLAN (2.4 ~ 2.484 GHz) and UWB (3.1 ~ 10.6 GHz) applications. The 3.5 GHz WiMAX band notched characteristic is achived by a pair of L-shaped slots instead of the previous U-shaped slot on the center of the radiating patch, whereas the 7.5 GHz band notched characteristic is achived by C-shaped strip resonator placed near to the microstrip feed line. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) is 8.62 GHz (2.38 ~ 11 GHz) which is sufficient to cover 2.4 GHz WLAN and UWB band, while measured band-notched bandwidths for 3.5 GHz WiMAX and 7.5 GHz bnad are 1.13 GHz (3.15 ~ 4.28 GHz) and 800 MHz (7.2 ~ 8 GHz) respectively. In particular, it has been observed that antenna has a good omnidirectional radiation patterns and higher gain of 2.51 ~ 6.81 dBi over the entire frequency band of interest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.40-46
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• 2002

In this paper we design and fabricate the Skeleton slot antenna which operates dually in GSM 900 and 1800 bands. Its simulation results are also compared with the measured ones. The original Skeleton slot antennas had the problems of unsatisfactory VSWR characteristics and considerably changing horizontal radiation patterns at high frequencies, but the proposed design improves these problems using multi-path feeding network and folding structure. The size of the radiator is 154 $\times$ 106(mm), and its height is 33(mm), and the reflector of 190$\times$190(mm) is used. The material of the radiator and reflector is 1mm-thick aluminum. Using NTC process reduces the mass production cost significantly. The measured return losses are 13.7 % at 900 MHz band and 16.4 % at 1800 MHz band, respectively. The horizontal radiation beam width is stable within $\pm$ 1$^{\circ}$ at both frequency bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.306-313
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• 2012

In order to enhance the isolation level between two dual-band E-slot microstrip patch antennas, EBG structure which operates in UMTS Tx(1.92~1.98 GHz) and Rx(2.11~2.17 GHz) band is proposed. The proposed EBG structure made with a periodic array of two different size EBG unit cells which has a modified mushroom-type for isolation improvement between two antennas. They do not share a common ground plane of the microstrip patch antenna. Overall size of the fabricated antenna is $210.5mm{\times}117mm$. The two different EBG unit cell sizes are $15.6mm{\times}4mm$ and $17.4mm{\times}4mm$, respectively. It was etched on the FR-4 substrate(thickness=3.93 mm, ${\varepsilon}_r$=4.6). The experiment results show that the isolation level between antennas in Tx/Rx band were improved by about 9 dB and 12 dB, respectively, through the use of the proposed EBG structure.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.344-351
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• 2016

In the present study, a dual-band multiple-input-multiple-output (MIMO) antenna covering WLAN frequency bands of 2.4 GHz (2.4 ~ 2.484 GHz) and 5 GHz (5.15 ~ 5.825 GHz) is newly presented to avoid use of decoupling structure for increasing isolation. The antenna consists of two L-shaped slots with n-shaped slots etched on the floating ground plane surrounded by open ended L-shaped slots which are placed in the left and right corner of PCB respectively. The proposed antenna is designed and fabricated on one side of FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm, and size of $50{\times}50mm2$. It has been observed that the measured impedance bandwidths ($S_{11}{\leq}-10dB$) are 0.3 GHz (2.28 ~ 2.58 GHz) in 2.4 GHz frequency band and 0.89 GHz (5.11 ~ 6 GHz) in 5 GHz frequency band respectively. In addition, It has been observed that the whole efficiency are more than 80 % in the whole operating frequency band and envelope correlation coefficient of the antenna is less than 0.05 as a very small value in spite of nothing of the decoupling structure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.546-550
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• 2003

For dual-band operation, it can be done by loading two pair of narrow slots in the equilateral-triangular patch, one embedded close to the side edges of the patch and the other inserted at the bottom edge of the patch. The obtained two operating frequencies are of same polarization planes. The frequency ratio of the two operating frequencies is turnabled by varing the positions and lengths of the inserted slots at the bottom edge of the patch. In this paper, A single-feed equilateral-triangular microstrip patch with two pairs of narrow slot for dual-frequency operation is printed on the substrate(TMN-4 Rosers Co.) of the 60 miles. the antenna radiation characteristics are calculated by Ensemble ver. 5.0 software, and compared with the experimental results.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.96-100
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• 2001

본 논문에서는 skeleton slot 복사기를 이용하여 GSM 900과 GSM 1800에서 사용할 수 있는 이중대역 안테나를 설계 및 제작하여 측정 결과를 비교 분서하였다. 기본적인 skeleton slot 구조에서는 낮은 밴드의 2배 이상의 주파수에서는 수평 빔폭이 일정치 않고, 정재파비 특성이 불량하였으나, 급전부와 측면 방사부분의 다중경로 형성 및 절곡 구조를 이용하여 이를 해결하였다. 안테나의 크기는 반사판이 190$\times$190(mm), 복사기는 154$\times$106(mm), 높이는 33mm로 하여 현재 서비스 사업자틀이 주로 사용하는 크기로 구성하였다. 구성 재질은 1mm 두께의 알류미늄판을 이용하며, 이를 NCT로 타공 및 절곡하여 제작하였기 때문에 대량 생산 시 단가를 낮출수 있다. 실측결과 900MHz 대역에서 13.7%, 1800MHz 대역에서 16.4%의 -l0dB 반사손실 대역폭을 만족하고, 방사패턴도 대역별로 $\pm$1$^{\circ}$이내의 일정한 양상을 보여 이중대역 안테나로서의 요구를 만족하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1131-1137
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• 1999

In this paper, a novel design method of an apertured coupled microstrip patch antenna with the single feeding structure is proposed for dual resonance frequencies with mutually perpendicular polarizations. The characteristics of this antenna are experimentally investigated. In order to achieve this goal, a new type of square patch with double notches is used as a radiator and the crossed slot and the bended mictrostrip feeder are adopted for the dual polarizations in the aperture-coupled structure. For the application of the proposed antenna, a Ku-band Tx/Rx $2\times$ subarray antenna is designed and manufactured. Also, the applicability of the antenna as a ground terminal is examined through performance analysis. According to the measurement, the gain of the antenna is 10dBi at the center frequencies of Tx and Rx, the side lobe level is lower than -13dB, and the cross polarization lebel is below 17 dB.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.960-966
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• 2018

Communication antennas used at sea have been developed remarkably. However, the speed of this development is insufficient when compared with user demands. Therefore, we developed an antenna for UWB/Bluetooth that operates on 3 [GHz] and 5.72 [GHz] bands in order to use the high-speed communication network system which improved antenna miniaturization, gain and radiation patterns. To improve bandwidth, a microstrip patch antenna was selected and CST Microwave Studio 2014 program was used. Through the program, we calculated the slot width, length, transmission line width, etc. using a theoretical formula at each step. These figures were checked through simulation to see if they meet production standards. UWB for high-speed wireless communication for short-range communication at sea, Bluetooth for exchanging information at a short distance by connecting each device, and corresponding technology can be easily utilized.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.3
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• pp.227-247
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• 2015

An X-band $8{\times}16$ dual-polarized active phased array antenna system has been implemented based on the substrate integrated waveguide(SIW) technology having low propagation loss, complete EM shielding, and high power handling characteristics. Compared with the microstrip case, 1 dB less is the measured insertion loss(0.65 dB) of the 16-way SIW power distribution network and doubled(3 dB improved) is the measured radiation efficiency(73 %) of the SIW sub-array($1{\times}16$) antenna element. These significant improvements of the power division loss and the radiation efficiency using the SIW, save more than 30 % of the total power consumption, in the active phased array antenna systems, through substantial reduction of the maximum output power(P1 dB) of the high power amplifiers. Using the X-band $8{\times}16$ dual-polarized active phased array antenna system fabricated by the SIW technology, the main radiation beam has been steered by 0, 5, 9, and 18 degrees in the accuracy of 2 degree maximum deviation by simply generating the theoretical control vectors. Performing thermal cycle and vacuum tests, we have found that the SIW array antenna system be eligible for the space environment qualification. We expect that the high efficiency SIW array antenna system be very effective for high performance radar systems, massive MIMO for 5G mobile systems, and various millimeter-wave systems(60 GHz WPAN, 77 GHz automotive radars, high speed digital transmission systems).