• Journal of IKEEE
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• v.27 no.1
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• pp.109-115
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• 2023

In this paper, we design and implement an Ultra-Wide Band (UWB, 3.1~10.6 GHz) antenna with 5G mobile communication (3.42~3.70 GHz) and Wireless Local Area Network (WLAN, 5.15~5.825 GHz) bands rejection characteristics. The proposed antenna consists of a planar radiation patch with two slots. The upper slot contributes to reject 5G mobile communication band and the lower slot contributes to reject WLAN band. The Voltage Standing Wave Ratio (VSWR) values of the proposed antenna show good performances in whole UWB band except for rejection bands based on VSWR 2.0. The proposed UWB antenna was simulated using High Frequency Struture Simulator (HFSS) by Ansoft. The simulated antenna showed dual rejection bands of 3.31~3.92 GHz and 5.04~5.90 GHz in UWB band, and measured antenna showed dual rejection bands of 3.35~3.97 GHz and 5.06~5.97 GHz. The largest VSWR values measured at each rejection band are 13.60 at 3.64 GHz and 10.25 at 5.52 GHz. The measured maximum gain is 5.31 dBi at 10.00 GHz. The lowest gains for the measured antenna at rejection bands are -8.73 dBi at 3.70 GHz and -4.36 dBi at 5.56 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.308-315
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• 2002

In this paper, the 5-bit digital phase shiftier with 10 InGaAs HEMTs is designed and fabricated for U.S. mobile DBS receiving active phased array antenna system in 12 GHz band. 11.25 $^{\circ}$, 22.5$^{\circ}$ and 45$^{\circ}$ phase bits are designed in leaded-line type. 90$^{\circ}$ and 180$^{\circ}$ phase bits are designed in reflection type combined with ring hybrid. The return loss more than 17.5 ㏈, insertion louts less than 7.8 ㏈, and maximum phase error of $\pm$6$^{\circ}$for 32 phase responses are measured in 12.2 GHz~ 12.7 GHz band.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.21-24
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• 2019

In this paper, 5.8GHz 25W microwave wireless power transmission system was developed. The transmission system is composed of a signal generator, a 1W drive amplifier, a 25W power amplifier, and a circularly polarized transmission antenna. The receiving system was fabricated with an integrated receiver that combines a circularly polarized receiving antenna, a pass band filter, and an RF-DC converter. And a multi-integrated receiver had twelve parts, including an integrated receiver. Under the conditions, voltage and current were measured for the system at 5cm intervals from a minimum distance of 5cm to a maximum distance of 80cm. The power was calculated for the system. The results of the system are shown in tables and graphs. The power decreases with distance, but the power does not drop sharply due to a multi-integrated receiver.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.97-102
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• 2023

In this paper, we fabricated transmitting and receiving antennas to realize the low cost radar using two receiving antennas and investigated their characteristics. The antennas are designed with MPA(Microstrip Patch Array) structure for the beam concentration in horizon direction and low cost and used Taylor array pattern synthesis to suppress sidelobes. As a results of measurement in the 24GHz ISM band(24.0-24.25GHz), our using band, antenna gains are placed between 15.2 dBi and 16.26 dBi which are satisfied with the design specification of higher than 15dBi and lower than 17dBi. The sidelobes are -13.15 dBc, -13.1 dBc and -12.8 dBc at the operating frequencies of 24.0 GHz, 24.125 GHz and 24.25 GHz repectively, which are satisfied with the specification of lower than -10 dBc.

• ETRI Journal
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• v.35 no.3
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• pp.534-537
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• 2013

A compact monopole antenna excited by a conductor-backed coplanar waveguide (CBCPW) is developed for wireless USB dongle applications. The proposed antenna has a compact dimension of $14mm{\times}47.4mm{\times}3.5mm$, which is suitable for a USB dongle housing. A slotted elliptical patch and a CBCPW with vertical vias are employed to achieve a further size reduction and an improved impedance bandwidth. The measurement result demonstrates that the fabricated antenna resonates from 2.25 GHz to 10.9 GHz, which covers all of the important wireless communication bands, including WiBro (2.3 GHz to 2.4 GHz), Bluetooth (2.4 GHz to 2.484 GHz), WiMAX (2.5 GHz to 2.7 GHz and 3.4 GHz to 3.6 GHz), satellite DMB (2.605 GHz to 2.655 GHz), 802.11b/g/a WLAN (2.4 GHz to 2.485 GHz and 5.15 GHz to 5.825 GHz), and ultra-wideband (3.1 GHz to 10.6 GHz) services. The radiation characteristics of the proposed antenna when attached to a laptop are tested to investigate the influence of the keypad and the LCD panel of the laptop.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1235-1239
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• 2010

In this work, a wideband technique has been proposed that improves the IF bandwidth of mixers and a 24-GHz down-conversion mixer employing the proposed technique has been designed and fabricated based on 0.13-${\mu}m$ RFCMOS technology. The mixer showed the conversion gain of $2.7{\pm}1.5$ dB from DC to 5.25 GHz IF for a fixed LO frequency of 24 GHz. Measured P-1dB and LO-RF isolation was -8.7 dBm and 21 dB, respectively. The mixer draws DC current of 10.6 mA from 1.3 V supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.435-443
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• 2009

In this paper, we propose a microstrip slot antenna that works in Bluetooth, Zigbee, WiMAX and WLAN frequency bands($2.4{\sim}5.825\;GHz$). To get the wide bandwidth from the microstrip antenna proposed, we insert a pair of parastic strips along the feed line on the FR-4 dielectric substance(${\varepsilon}_r=4.8$). Furthermore, a simple geometrical rotation with quadrilateral slot is designed to maximize the bandwidth and to gain a wider frequency band than the conventional rectangular slot antenna. A additional design of the loop type is added to a cactus-shaped patched for 2.4 GHz ISM frequency band. The total measured bandwidth of the antenna is from 2.4 GHz to 6 GHz and the maximum gains of the antenna are 3.82 dBi, 4.48 dBi, 6.41 dBi and 6.65 dBi at the frequencies of 2.4 GHz, 3.5 GHz, 5.25 GHz and 5.77 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1701-1706
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• 2000

In this work a 38 GHz hybrid 2-stage power amplifier module using GaAs pHEMTs and waveguide to microstrip transitions has been successfully developed. A 10 mil thickness duroid substrate was use for fabrication of the power amplifier and the waveguide to microstrip transitions. The fabricated waveguide to microstrip transition showed about 1 dB insertion loss(back to back) at 32-40 GHz. The measured results of power amplifier module showed 29 dBm output power(P1.5dB), 7,2 dB associated gain and 11.2% power-added efficiency(PAE) at 36.8-38.5 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.709-715
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• 2002

In this paper, a novel low profile dual feeding microstrip antennas with microstrip and H-shaped aperture feeding are proposed to achieve high isolation and easy feeding, and the validity of the proposed antennas is demonstrated experimentally. In the proposed single and 1$\times$4 array antenna, the measured isolations are less than -49 dB and -48 dB, impedance bandwidths are 4 % at 12.5 GHz and 2.1 % at 14.25 GHz for the VSWR<1.5 in both antennas and maximum gains are 8.25 dBi and 14.2 dBi.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.691-692
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• 2016

본 논문은 802.11a 무선 랜용 5.25-GHz BiCMOS 저 잡음 증폭기를 제안한다. 이러한 회로는 1볼트 전원에서 동작하며, 저 전압 전원 공급에서도 높은 전압 이득을 가지도록 설계하였다. 제안한 회로는 $0.18{\mu}m$ SiGe HBT BiCMOS로 설계되어 있다. 저 전압 및 저 전력 동작을 위해 바이어스 회로는 밴드 갭 참조 (band-gap reference circuit) 바이어스 회로를 사용하였다. 제안한 회로는 최근 발표된 연구결과에 비해 높은 전압이득, 낮은 잡음지수 및 작은 칩 크기 특성을 보였다.