• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2763-2768
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• 2013

In this paper, a design method for a compact slot antenna for 5.8 GHz RFID band (5.725-5.875 GHz) is studied. The proposed slot antenna is size-reduced by bending both ends of the straight slot in "I"-shape, and a rectangular feed patch is located inside the slot. The effects of slot length, location of feed patch, and width and length of feed patch on the antenna performance are examined. A prototype antenna with optimized parameters for 5.8 GHz band is fabricated on an FR4 substrate and tested experimentally to verify the results of this study. The experimental results show that the frequency band for a VSWR < 3 ranges 5.72-6.13 GHz (bandwidth 410 MHz), and it corresponds fairly well with the simulated band 5.64-5.97 GHz (bandwidth 330 MHz). The fabricated antenna shows good radiation performance such as maximum power density in both directions normal to the slot plane, low cross-polarization level of < -20 dB, and realized gain > 0 dBi within the frequency band.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1659-1665
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• 2019

In this paper, a novel design of a compact printed monopole antenna for wireless local area network (WLAN) applications is investigated. The radiator with a patch of different line width and step-shaped ground planes is used to reduce the antenna size. The size of the antenna is 16 × 17 × 1 ㎣ and is fabricated with a photolithography technique. The simulated and measured results agree well. The resonant frequency of the investigated antenna is about 5.2 GHz and can cover an impedance bandwidth of 1 GHz for the measurement result. In addition, we presented the measured radiation pattern, presented the gain and efficiency measured in the required WLAN 5 GHz frequency band (5.15-5.825 GHz), and confirmed that it can be used as a 5 GHz band WLAN antenna. The investigated antenna has a small size, light weight, low cost, omni-directional radiation pattern, high gain, and high efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.5
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• pp.337-343
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• 2013

In this paper, IEEE 802.11 based WLAN(5.2/5.8GHz) wideband Weathercock-shaped microstrip patch antenna was designed and manufactured. The antenna has a size of $17.4{\times}17.4mm^2$ and utilized FR-4 board. The size was minimized for mobility, and Weathercock-shaped U-slot and short-pin was inserted to satisfy adequate bandwidth and double bandwidth resonance characteristics. In addition, the antenna incorporated single both-sided patch, and simulation design optimized the Weathercock-shaped, position of the U-slot and the short-pin, and the length of the patch for the measurement. The manufactured antenna achieved a bandwidth of 695MHz from 5.2~5.8GHz zone(Return loss<-10dB). Achieved a beam width of $81.13^{\circ}$ and $85.43^{\circ}$ for 3-dB beam width of H plane and E p;ane radiation pattern, there was 3.17~4.85dBi gain.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.5
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• pp.123-127
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• 2017

This paper fabricated and analyzed the image rejection mixer that uses FET's channel resistance. It can be applied for capacity 64QAM that has 50MHz~90MHz of IF band, 8.17GHz of LO frequency and 8.08~8.12GHz of RF band. When IF input power is -20dBm and LO input power is 10dBm, RF output power is obtained -33.2dBm. In this case, conversion loss is 12.9dB, the suppression of 14.3dB for LO frequency and 10.4dB for image frequency. The result of two tone test shows great IMD characteristics with 51.7dBc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.312-319
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• 2005

In this paper, a meander-type microstrip patch antenna for application in 5GHz-band is designed and fabricated. To obtain enough bandwidth in VSWR<2, the foam is inserted between substrate and ground plane, the coaxial probe source is used. Antenna is simulated varing the length and width of meander line, the position of probe feeding and the thick of airgap. Later anterlna is fabricated with optimizated antenna parameter. The measured result of Fabricated antenna obtained $1GHz(17.5\%)$ bandwidth in VSWR<2$, the gain of $.3\sim9.5$dBi, Unidirectional pattern.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1031-1040
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• 2023

Propagation characteristics in line-of-sight(LOS) paths in 3, 6, 10, and 17 GHz frequency bands were measured and analyzed in two different indoor corridors: second floors of Buildings D2 and E2. The measurement was designed to measure when the receiving antenna moved at 0.5 m intervals from 3 m to 30 m, while the transmission antenna was fixed. The analysis of the two indoor corridors was compared by applying basic transmission loss, root mean square (RMS) delay spread, and K-factor. For basic transmission loss, the loss coefficient of the floating intercept path loss model was higher in the indoor corridor of Building E2 than in that of Building D2. Similarly, the RMS delay spread in the time domain was greater in the indoor corridor of Building E2. However, the indoor corridor of Building D2 exhibited higher K-factor in the 3, 6, and 17 GHz bands with lower wave propagation in the 10 GHz band. Despite the 2 indoor corridors being identical, the propagation characteristics varied due to different internal structures and materials. The results provide measurement data for ITU-R Recommendations regarding various indoor environments.

• ETRI Journal
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• v.42 no.4
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• pp.549-561
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• 2020

We developed a 0.1-㎛ metamorphic high electron mobility transistor and fabricated a W-band monolithic microwave integrated circuit chipset with our in-house technology to verify the performance and usability of the developed technology. The DC characteristics were a drain current density of 747 mA/mm and a maximum transconductance of 1.354 S/mm; the RF characteristics were a cutoff frequency of 210 GHz and a maximum oscillation frequency of 252 GHz. A frequency multiplier was developed to increase the frequency of the input signal. The fabricated multiplier showed high output values (more than 0 dBm) in the 94 GHz-108 GHz band and achieved excellent spurious suppression. A low-noise amplifier (LNA) with a four-stage single-ended architecture using a common-source stage was also developed. This LNA achieved a gain of 20 dB in a band between 83 GHz and 110 GHz and a noise figure lower than 3.8 dB with a frequency of 94 GHz. A W-band image-rejection mixer (IRM) with an external off-chip coupler was also designed. The IRM provided a conversion gain of 13 dB-17 dB for RF frequencies of 80 GHz-110 GHz and image-rejection ratios of 17 dB-19 dB for RF frequencies of 93 GHz-100 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.1
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• pp.8-14
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• 2016

In this paper, a compact CPW-fed antenna for 5 GHz (5.15-5.35 GHz, 5.725-5.825 GHz) band WLAN applications is presented. The designed antenna's shape is step structure. The antenna is fabricated and measured into FR-4 substrate of dielectric comstant 4.2 and thickness 1.0 mm with optimized parameters obtained by simulation. We confirm that it is operated as antenna for WLAN applications by obtaining the measured return loss level of < -10 dB in 5.133-5.982 GHz. The dimensions of the antenna ($20.0{\times}16.0{\times}1.0mm^3$) shows an compactness of about 67.17% with respect to a conventional folded slot antenna.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.2 s.332
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• pp.75-80
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• 2005

In this paper, 2-stage power amplifier has been designed for 5.8GHz wireless LAN application. The power amplifier PldB output power has 21.6dBm at 5.8GHz frequency. Also the power amplifier shows 17.6dB gain and -17.8dB input return loss at 5.725GHz to 5.825GHz. The OFDM modulation and transmission block have been modeled in order to analyse the relationship between the power amplifier distortion and output ACPR for the IEEE 802.11a wireless LAN. The nonlinear characteristic of the power amplifier has been modeled as AM-to-AM and AM-to-PM using the behavioral model, and the output spectrum is analysed with the phase distortion variation. Also, amplifier back-off value from PldB to satisfy the required IEEE 802.11a standard spectrum mask has been simulated with phase distortion, and the simulation data have been compared to the measurement result collected by using the pre-distortion technique.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.42-50
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• 2007

This paper presents design methods for dual-frequency(2.4/5.8GHz) active receiving antennas. The proposed active receiving antennas are designed to interconnect the output port of a wideband antenna to the input port of an active device of High Electron Mobility Transistor directly and to receive RF signals of 2.4GHz and 5.2GHz simultaneously where the impedance matching conditions are optimized by adjusting the length of $1/20{\lambda}_0$(@5.8GHz) CPW transmission line in the planar antenna The bandwidth of implemented dual-frequency active receiving antennas is measured in the range of 2.0GHz to 3.1GHz and 5.25GHz to 5.9GHz. Gains are measured of 17.0dB at 2.4GHz and 15.0dB at 5.2GHz. The measured noise figure is 1.5dB at operating frequencies.