• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.3
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• pp.35-42
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• 2000

A cross-shaped microstripline-fed printed slot antenna having wide bandwidth Is presented in this paper. The proposed antenna is analyzed by using the Finite-Difference Time-Domain (FDTD) method. It was found that the bandwidth of the antenna depends highly on the length of the horizontal and vertical feedline as well as the offset position of the feedline. The maximum bandwidth of this antenna is from 1.975 GHz to 4.725 GHz, which is approximately 1.3 octave, for the VSWR $\leq$ 2. Experimental data for the return loss and the radiation pattern of the antenna are also presented. and they are in good agreement with the FDTD results.e FDTD results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.885-892
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• 2013

The main advantage of ESPAR antenna is that ESPAR antenna requires only a single RF chain for reduction of transceiver's hardware complexity, as compared to conventional MIMO system. In conventional MIMO system, each data symbol is mapped to each antenna. But, each data symbol is mapped to each orthogonal basis pattern in ESPAR antenna system. In this paper, we design beamspace MIMO system using ESPAR antenna with single RF chain for MIMO system of low-complexity and low power consumption. And then, we analyze performance of beamspace MIMO according to each PSK modulation. Performance of beamspace MIMO system is similar to performance of conventional MIMO system. As a result of analyzing the performance of beamspace MIMO system using higher-order PSK modulation. we can confirm that performance characteristic of beamspace MIMO system with low complexity and low power consumption is similar to digital communication of signal domain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.3
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• pp.305-316
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• 1998

The impedance matching network with the simplfied real frequency technique (SRFT) is proposed as a method for bandwidth enhancement of microstrip antenna. The validity of the technique is based on the relative frequency insensitivity of the radiation pattern and gain characteristics as compared to the resonant behaviour of the input impedance. The most significant feature of this technique is that there is no need to find any analytical description of the antenna and generator, and it only utilizes directly real frequency generator and load data over the prescribed frequency band. Furthermore, it is not necessary to invent an analytic form of the system transfer function to assume a matching network topology in advance. In this paper, the transmission line model is used to investigate the rectangular microstrip antenna, and based on the Fano's bandwidth-enlargement theory, the SRFT is introduced to design the matching networks of microstrip antennas in order to obtain a constant gain over the frequency band of interest. Two representative microstrip antnnas with different structure are fabricated and tested. From these procedures, it is obtained that the proposed impedance matching networks of microstrip antenna improve the impedance bandwidth nearly three times compared to the antenna without them.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.985-997
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• 1999

In this paper, the detection of 1 g and 10 g averaged SAR on human head caused by PCS handheld phones is analyzed and discussed. Conventional monopole antenna and planar structured PIFA are used in the computational model to apply to the antennas mounted on handheld phone. These antennas are designed to operate in the near of frequency 1.8 GHz, human head model is sampled to have cell size 1.5 mm and sloped to front direction by 30$^{\circ}$. It is found that, when monopole antenna is applied, 1 g averaged SAR is 1.4 W/kg, 10 g averaged SAR is 0.7 W/kg, when PIFA is applied, for each case, SARs are 1.143 W/kg, 0.4866 W/kg. While the radiation pattern of the monopole antenna is symmetrical, that of planar structured antenna is asymmetrical and SAR caused by PIFA is less than SAR by the monopole antenna. The radiation efficiency of PIFA is 62.6%, which is higher than that of monopole, 53%.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.805-811
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• 2008

This paper presents a design of RFID(Radio Frequency Identification) tag antenna which is available for a vehicle's side mirror and directivity characteristics by mr body. The proposed Tag antenna is designed symmetrical structure to improve the broad bandwidth characteristic and the readable range. A proposed tag antenna($30\;mm{\times}24\;mm{\times}1\;mm$) has resonant frequency at 910 MHz and bandwidth is 780 MHz ($540\;MHz{\sim}1320\;MHz$). The chip impedance is the 16 - $j131\;{\Omega}$ and the complex conjugate impedance of commercial chip has been used for tag antenna design. In order to evaluate effects of tag antenna for side view mirror's permittivity as well as car body(conductor), radiation pattern characteristics and readable range have been calculated and measured. The optimized position for a vehicle's RFID system has been observed in the inside of a side mirror and the calculated results show good agreement with the measured results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.17-23
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• 2021

In the present study, a more compact dual-band slot antenna is newly proposed for Wi-Fi application. The proposed antenna is composed of rectangular two stepped slot with open end which can generate standing wave resonance at dual frequency bands and L-type microstrip feed line. The measured impedance bandwidths are 50 MHz(2.412 ~ 2.470 GHz) at low frequency band and 452 MHz(5.451 ~ 5.903 GHz) at high frequency band respectiviely. Furthermore its size of 14 × 21 mm² is reduced by 30% compared to the size of 20 × 21 mm² of a conventional similar compact slot antenna. It has the omni-directional radiation pattern characteristics of a typical dipole antenna on the H-Plane, so it is suitable for commercial wireless network applications such as Wi-Fi.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.6
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• pp.438-444
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• 2019

In this paper, we proposed a 16-element array antenna design to improve signal detection performances. The array antenna characteristics, such as mutual coupling, pattern deviation, and half power beamwidth of the active element, were examined to obtain an optimal spacing between individual elements. The single element of the array antenna consists of an indirect feed using L-shaped feed and shorted radiating patch to achieve a broadband operation. Root mean square(RMS) errors based on the incident angle of the signal were calculated to verify the signal detection performance of the proposed antenna. The results demonstrate that the proposed array antenna with optimal spacing is suitable for detecting interference signals with low RMS error.

• Journal of Advanced Navigation Technology
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• v.26 no.1
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• pp.29-34
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• 2022

In this paper, the design of a triple dipole quasi-yagi antenna operating in the 2.45 GHz and 5 GHz wireless LAN frequency bands and the 3.5 GHz WiMAX frequency band was studied. The proposed quasi-Yagi antenna consists of three dipoles connected in series with a V-shaped ground plane. The longest half-bow-tie-shaped dipole resonates in the 2.45 GHz band, whereas the medium-length dipole resonates at 3.5 GHz. The shortest dipole resonates in the 5 GHz band. By adjusting the length and width of the dipoles and the spacings between the dipoles, a triple-band directional antenna operating in the 2.45 GHz, 3.5 GHz, and 5 GHz bands are designed, and fabricated on an FR4 substrate with a size of 45 mm × 55 mm. It was confirmed that the fabricated antenna operates in the designed triple bands of 2.32-2.57 GHz, 3.26-3.69 GHz, and 4.50-6.56 GHz for a voltage standing wave ratio less than 2. Gain is maintained above 3 dBi in the three bands.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.127-134
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• 2022

A modified folded monopole slot antenna for 3G WCDMA (1.91 ~ 2.17 GHz), 4G LTE (2.17 ~ 2.67 GHz), 3.5 GHz 5G (3.42 ~ 3.7 GHz) and Wi-Fi dual band (2.4 ~ 2.484 GHz / 5.15 ~ 5.825 GHz) was proposed for the first time. The proposed antenna is designed and fabricated on a FR-4 substrate with dielectric constant 4.3, thickness of 1.6 mm, and size of 35 × 60 mm². The measured impedance bandwidth of the proposed antenna is 2910 MHz(1.84 ~ 4.75 GHz) and 930 MHz(5.11 ~ 6.04 GHz), antenna gain in each frequency band is from 1.811 to 3.450 dBi. In particular, it was possible to obtain a commercially suitable omni-directional radiation pattern in all frequency bands of interest.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.245-254
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• 2022

In this paper, a design optimization method for anti-jamming GPS antenna is presented. For this purpose, jamming performance analysis criteria and methods are presented. And based on the proposed analysis method, the antenna design elements that can realize the best performance were optimized. The anti-jamming GPS antenna for applying the presented method has a structure in which 7 radiating elements are arranged. Here, six radiating elements were circular arranged, and one element was arranged in the center of the circular arrangement. The optimized antenna design parameter(radius of the circular array) is 0.48 λ. As a result of the simulation, it was confirmed that when the steering angle(theta, phi) of the main lobe was (0°, 0°), the pattern null steering range(based on theta) was 57° to 90°.