• ETRI Journal
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• v.41 no.4
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• pp.536-548
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• 2019

In this study, an electronically steerable parasitic array radiator (ESPAR) antenna via analog radio frequency (RF) switches for a single RF chain MIMO system is presented. The proposed antenna elements are spaced at ${\lambda}/64$, and the antenna size is miniaturized via a dielectric radome. The optimum reactance load value is calculated via the beamforming load search algorithm. A switch simplifies the design and implementation of the reactance loads and does not require additional complex antenna matching circuits. The measured impedance bandwidth of the proposed ESPAR antenna is 1,500 MHz (1.75 GHz-3.25 GHz). The proposed antenna exhibits a beam pattern that is reconfigurable at 2.48 GHz due to changes in the reactance value, and the measured peak antenna gain is 4.8 dBi. The reception performance is measured by using a $4{\times}4$ BPSK signal. The measured average SNR is 17 dB when using the proposed ESPAR antenna as a transmitter, and the average SNR is 16.7 dB when using a four-conventional monopole antenna.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.156-161
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• 2006

In this paper, GPS/IMT2000/Wireless LAN compact chip antenna is designed for mobile communication system. The proposed antenna size is $10.2mm{\times}21mm{\times}1mm$. It consists of three meander lines. dual resonance frequencies is achieved by two effective current paths using two meander lines and via. also The parasitic meander line structure is added. The coupling is adjusted by arranging parasitic meander line for triple-band. The fabricated antenna achieve triple-band. The resonance frequencies are 1.672GHz, 2.092GHz, 2.504GHz. The impedance bandwidths of each resonance frequencies are 156MHz, 272MHz, 64MHz. The maximum radiation gains of fabricated antenna are 0.08dBi, 1.67dBi, -1.44dBi. The proposed antenna achieve quasi monopole radiation pattern.

• Journal of Advanced Navigation Technology
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• v.24 no.3
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• pp.232-237
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• 2020

In this paper, a compact microstrip-fed dual-band planar antenna for global positioning system (GPS) and mobile handset applications is presented. Dual operating frequency bands are achieved by an open end L-shaped slot and a bent rectangular slot. The proposed antenna is designed and fabricated on the FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm and size of 57 × 57 ㎟. The measured impedance bandwidth (|S₁₁|≤ -10dB) of the fabricated antenna is 60 MHz(1550 ~ 1610 MHz) in the GPS band and 670 MHz (1690 ~ 2360 MHz) in the DCS / IMT-2000 band, covering the required bandwidths for GPS(1570 ~ 1580 MHz) and DCS / IMT-2000 (1710 ~ 2200 MHz) bands. In particular, it has been observed that antenna has a good omnidirectional radiation patterns as well as high gain of 2.36 dBi and its efficiency is more than 90 % over the entire frequency band of interest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.148-157
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• 2015

In this paper, we propose a compact antenna hat to perform RF compatibility testing efficiently between the launch vehicle and ground stations. The proposed structure implements a small size and low loss using the conductive shield instead of the conventional RF absorber. The S-band antenna hat, which is fabricated for an inverted-F onboard antenna with the size of $74mm{\times}13mm{\times}16mm$, has the small enclosure of $88mm{\times}35mm{\times}44mm$, the return loss of 25.6 dB, the insertion loss of 0.26 dB, and the leakage loss of 49.4 dB at the center frequency of 2.25 GHz. The simulated and measured results show a good agreement.

• Journal of Advanced Navigation Technology
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• v.13 no.2
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• pp.244-251
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• 2009

In this paper, a compact slot antenna for 2.4GHz ISM band applications has been designed. The folded slot with some additional meander sections are used in the design of the antenna within the restricted PCB space. The operating frequency band and the fractional bandwidth of the antenna is about 2.32~2.58 GHz and 11%, and the radiation patterns within the operation bandwidth are almost same. Also, the radiation efficiency and gain of the antenna is more than 49% and 1.2 dBi respectively. To check the validity of the design result, the measurement and simulation results are compared and presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.798-805
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• 2017

This paper presents a low profile multi circular ring with different radius, patch antenna with modified feed line and slotted ground. The size of the antenna is $15{\times}12mm^2$, having electrical dimensions of $0.14{\lambda}{\times}0.12{\lambda}$ (at lower initial frequency) and footprints of $180mm^2$. The proposed antenna covers 3.1 to 12.3 GHz, reflection coefficient up to -38 dB with Bandwidth ratio of 4.13:1 and fractional Bandwidth of 122%. Bandwidth dimension ratio has been calculated (which is 6246) as a proof for compact size. Thin slots introduced on the feed line provide good impedance matching for whole frequency band. Numerical simulations of the proposed antenna are reported in terms of reflection coefficient ${\leq}-10dB$, vswr 2:1, radiation pattern and group delay (ns). The proposed antenna has advantage of very small size along with better impedance match that provides a practical approach to realize it for BW enhancement and UWB applications.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.50-55
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• 2002

In this paper, Ive propose a bow-tie-shaped meander slot antenna find by a microstrip line to achieve compact size as well as wideband characteristic. While conventional bow-tie slot antennas exhibit wide band characteristic, they have relatively large size. On the other hand, the meander slot antennas are very small, but they reveal quite narrow bandwidth (typically less than 1 %). To realize miniaturized antennas balling large bandwidth, combination of the bow-tie slot and the meander slot geometries is proposed in this paper. Theoretical results show that the proposed antenna with uniform slot width is 65.5 % smaller than that of the conventional bow-tie antenna in size, while the bandwidth is 3 times larger than that of the meander slot antenna. Moreover, the non-uniform slot width antenna shows 60 % smaller in size and about 3.5 times wider in bandwidth than the previous antennas. Measured antenna performance reveals excellent agreement with the predicted values.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.331-337
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• 2015

A novel fully-printed microstrip antenna with negative first resonance and dual polarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1st resonance results from a composite right- and left-handed(CRLH) structure that has a circumferentially interlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is provided with a dual-polarization capability by creating two orthogonal linear polarizations in one body with coaxial feeds. The design is carried out by doing full-wave EM field simulation which is compared with the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBi and the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel of the bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.40-41
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• 2009

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.237-240
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• 2002

In this paper, we designed and implemented the dual band antenna for IMT-2000 and 5.7㎓ WLAN(Wireless Local Area Network). The antenna was designed by using 3D simulations program, HFSS(High Frequency Structure Simulator). The electrical characteristics were measured by using HP 8720C network analyzer and measured maximum S$\sub$11/ was -25㏈, and maximum VSWR(Voltage Standing Wavc Ratio) was 1.26 for all frequency bands of interests in IMT-2000 and 5.7㎓ WLAN. Simulation results for antenna gain at 2㎓ and 5.7㎓ were 1.31㏈i and 4.1㏈i with omni directional radiation pattern. Implemented antenna is compact sized and can be produced in low cost enough for commercialization.