• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1740-1746
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• 1997

In this paper, a waveguide-fed slot-coupled microstrip antenna is proposed as enhanced feeding structure of microstrip antenna and an analysis is presented. The presence of dielectric substrate between a stripand a slot is explicitly taken into account in this analysis. The evaluation of the antenna characteristics is carried out using the method of mements and the spectral domain approach in terms of the electric current distribution on the strip and the magnetic current distribution on the slot. From the results, we can conclude that the proposed structure is adequate for array antennas, due to ease of mass porduction and enhanced anteena performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.45-53
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• 2019

In this paper, three types of array antennas for 5G mobile devices operating at 28 GHz were designed, and their performances were compared. The isolation between antenna elements was compared based on $S_{21}$. The $S_{21}$ of dipole, slot, and patch type are -13.76 dB, -16.88 dB, and -11.47 dB, respectively, with the slot-type antenna having the highest isolation. In order to compare the beam coverage performance, several characteristics such as beam width and maximum beam steering angle were analyzed. The analysis shows that the slot type has the widest steering angle of $63^{\circ}$ while the patch type has narrowest with $36^{\circ}$. In addition, to verify the performance of the antennas in the actual usage environment of the device, antenna characteristics in talk mode and data mode were analyzed through simulation. The results confirmed that the slot-type array antenna is the most suitable array antenna element for 28 GHz 5G mobile devices.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.107-115
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• 2005

This paper presents the structure of a broadband coplanar waveguide(CPW) fed square slot antenna with a impedance bandwidth tuning patch. The designing method of the antenna suggests that two resonant frequencies are excited as a dual-frequency dipole antenna following the dimensions of the square slot. In other words, the lower resonant frequency mainly depends on the slot width and the higher one its length. A CPW fed square slot antenna with a impedance tuning patch was measured to $20GHz^\~33GHz$, $50\%$, VSWR=2 impedance bandwidth by adjusting the dimensions of the tuning patch when the slot length had $70\%$ of its width. This result shows that a medical CPW fed antenna is easily implemented with a simple square slot structure including a bandwidth tuning patch in the center.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.400-405
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• 2018

This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.209-216
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• 2003

We design and fabricate slot array antenna for BMWS(Broadband Multimedia Wireless System) applications. This paper presents a simple feed structure, which consists of two horns and a parallel-plate waveguide, because antennas operating at 40.5 GHz~43.5 GHz have considerable feeding losses. The simple feed structure has the advantages of high-efficiency and mass-production. The fabricated antenna has a gain of 25.8 dBi with a sidelobe level below -18 ㏈ and a 3 ㏈ beamwidth of approximately 3$^{\circ}$ in the E-plane. In case of H-plane, a 3 ㏈ beamwidth is 17$^{\circ}$ and a sidelobe level is suppressed to below -27 ㏈. The experimental results are in good agreement with the simulation results. The authors expect that narrow 3 ㏈ beamwidth is obtained by combining a few proposed slot array antennas in parallel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.4
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• pp.349-356
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• 2015

In this paper, MIMO antenna with low correlation for LTE band 5(824~894 MHz) was designed by adopting monopole antenna and slot antenna. Based on ground characteristic mode theory, MIMO antenna was designed using different types of antennas for enhancement of correlation. MIMO antenna using PIFA and slot type antennas is proposed and correlation coefficient was compared with MIMO antenna using two PIFAs. Average correlation coefficient of MIMO antenna using two PIFAs was 0.71 but the proposed MIMO antenna had very low correlation coefficient of 0.17.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.535-540
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• 2004

In this paper, We proposed a rectangular slot antenna with CPW feeder. Slot antennas fed by CPW are attractive due to the simple fabrication simplicity and ease of integration with active devices. This antenna consists of two parts, inner patch and outer patch to realize wide-band antenna by multi-frequency. Also, We fabricated a proposed rectangular slot antenna, confirm characteristics of multi-frequency by tuning antenna parameters, inner antenna's location and size. The experimental results show that each resonant frequency of a fabricated antenna is measured at almost 1, 9GHz, 2.8GHz, 3, 5GHz, 4, 9GHz. In radiation patterns each resonant frequency, radiation pattern 4-th resonant frequency is the same ad that of TM11 in patch antenna. Therefore, the experimental and theoretical results shows that a proposal rectangular slot antenna have triple resonant frequencies.

• 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.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.503-507
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• 2007

In this paper, the ultra-widebend, microstrip patch antenna with the bandwidth of 3 GHz was implemented for ultra-wideband(UWB) wireless communication applications. In order to cover the very wide bandwidth of 3 GHz, a multi-resonance antenna was designed, each resonance frequency was separated into five frequency bend, 7.5, 8.1, 8.7, 9.3, and 9.9GHz with the interval of 600MHz BW. And for wideband characteristics of each antenna, U-slot antennas were designed at each center frequency. Designed five U-slot antennas were connected in series for multi-resonance of 3GHz BW and wideband matching was also designed for impedance matching transmission line calculated. The relative dielectric constant, the height, the loss tangent of the PCB substrate were ${\epsilon}_r=4.8,\;h=0.6$ and loss tangent=0.0009 respectively. The implemented antenna's radiation patterns and gain were directivity characteristics and $1.46{\sim}4.08dBi$ at the five separated center frequency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3140-3145
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• 2012

In this paper, a design method for a compact slot antenna fed by a coplanar waveguide (CPW) is studied. A T-shaped tuning stub is inserted inside a narrow rectangular slot and the slot is impedance matched to the CPW feedline by adjusting the width, length, and position of the stub. The resonance frequency is adjustable by the slot length and the antenna size can be reduced by bending the slot. The resonance frequency and impedance matching property of the compact slot antenna are similar to those of the half-wavelength slot antenna, which enables one to design compact antenna of this type with ease. A compact slot antenna for 2.45-GHz ISM band is designed, fabricated on an FR4 substrate (dielectric constant of 4.4 and thickness of 0.8 mm), and experimentally tested. The measured results agree well with the simulations, which confirms the validity of this study. The fabricated compact slot antenna shows an impedance bandwidth of 200 MHz(2.32-2.52 GHz) for a VSWR < 2, which is suitable for 2.45-GHz ISM band (2.4-2.48 GHz). The measured radiation patterns show ${\infty}$-shaped directional pattern in the E-plane and nearly omni-directional pattern in the H-plane with a peak gain of 2.0 dBi, which are similar to those of a monopole antenna. The proposed antenna is expected to be suitable for the applications as antennas for WLAN, RFID, and mobile handset.