• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.515-519
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• 2015

In this paper, we suggested the novel monopole antenna for dual band characteristics by a linear monopole antenna combined with crossed planar monopole antenna. The target frequency is ISM(Industrial Scientific Medical) 2.45GHz/5.8GHz. The distinctive features of the proposed antenna in this paper is based on the slit in the surface of a crossed planar monopole for the dual band characteristics and the omnidirectional radiation patterns. The compact size of the proposed antenna is $36mm{\times}5.4mm{\times}5.4mm$. According to the simulation results, the bandwidth, the reflection coefficients below -10dB, of 2.45GHz and 5.8GHz are 150MHz and 1.43GHz, respectively. Consequently the proposed antenna structures is apply to the antenna for dual band characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.401-408
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• 2001

This paper shows the design, fabrication and performance analysis of VCO which plays a major role in 5.8 GHz RF module for ITS. The design specifications of the VCO are determined on the basis of 5.8 GHz RF modul performance requirements. The design parameters are optimized through ADS simulation tool. The operating characteristic and performance analysis of the implemented VCO based on the design parameters are accomplished. The frequency variations according to the voltage change(0 ~5 V) of varactor diode are from 5.42 GHz to 5.518 GHz and the power level is 6.5 dBm. The second harmonic suppression are -21.5 dBc at 5.51 GHz and the phase noise characteristics are -83.81 dBc at 10 kHz offset frequency. The implemented VCO is available to not only DSRC and also, 5.8 GHz other systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.869-872
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• 2005

This paper presents a new switchable dual mode VCO(Voltage-Controlled Oscillator). The VCO is efficient in dual mode operation and has self-bias adjustment based on the operation frequencies of 2.4 GHz and 5 GHz. The switching is done using MOS transistors and tuning is done using MOS varactors. It is implemented using TSMC 0.18${\mu}$m CMOS technology. It is powered by 1.8V supply. The measured results showed that the overall tuning range is approximately 13% at 5 GHz and 8% at 2.4 GHz. The measured phase noise is approximately -102 dBc/Hz at 1 MHz offset for 5 GHz and -89 dBc/Hz at 600kHz offset for 2.4 GHz. The VCO showed tail currents of 2mA in 5GHz mode and 2.5mA in 2.4GHz mode from a 1.8 V supply, respectively.

• 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.

• Journal of Advanced Navigation Technology
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• v.21 no.2
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• pp.193-199
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• 2017

In the paper, a dual band-notched monopole antenna is proposed for 2.4 GHz WLAN (2.4 ~ 2.484 GHz) and UWB (3.1 ~ 10.6 GHz) applications. The 3.5 GHz WiMAX band notched characteristic is achived by a pair of L-shaped slots instead of the previous U-shaped slot on the center of the radiating patch, whereas the 7.5 GHz band notched characteristic is achived by C-shaped strip resonator placed near to the microstrip feed line. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) is 8.62 GHz (2.38 ~ 11 GHz) which is sufficient to cover 2.4 GHz WLAN and UWB band, while measured band-notched bandwidths for 3.5 GHz WiMAX and 7.5 GHz bnad are 1.13 GHz (3.15 ~ 4.28 GHz) and 800 MHz (7.2 ~ 8 GHz) respectively. In particular, it has been observed that antenna has a good omnidirectional radiation patterns and higher gain of 2.51 ~ 6.81 dBi over the entire frequency band of interest.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.6
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• pp.116-126
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• 2008

This paper describes the Dual-band WLAN transmitter with 2.4[GHz], 5[GHz]. Dual-band WLAN transmitter was designed at 2.4[GHz] and 5[GHz]. The Dual-band WLAN transmitter has a amplifier which operate at 2.4[GHz] and 5[GHz] frequency and two VCO(Voltage Controlled Oscillator) or VCO has a wide scope of frequency. these problem cause a size and a power consumption, The Dual-band WLAN transmitter module was proposed to solve these. the transmitter was designed to get output signals of IEEE 802.11a's 5.8[GHz] band signal using frequency multiplication way or to act a amplifier about the 2.4[GHz] band signal of IEEE 802.11b/g, according to inputed frequency and bias voltage that a eve using single transmission block. The output spectrum get the improved specification of ACPR of 4[dB], 6[dB], 16[dB] at +11[MHz], +20[MHz], +30[MHz] offset of center frequency compared to no linearization, was satisfied to transmit spectrum mask of IEEE 802.11a wireless Lan.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.436-441
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• 2018

In this paper, a design method for a compact double dipole quasi-Yagi antenna with a V-shaped ground plane operating in dual bands including 2.45 GHz and 5 GHz wireless LAN frequency bands is studied. First, a quasi-Yagi antenna operating in the 2.45 GHz band is designed, and a V-shaped ground plane is used instead of a conventional strip ground plane to reduce the length of the antenna. A second dipole is connected to the dipole driver of the quasi-Yagi antenna for 2.45 GHz band and a director is appended for 5 GHz band operation. A prototype of the proposed dual-band antenna operating at 2.45 GHz WLAN band and 4.57-7.11 GHz band is fabricated on an FR4 substrate with a dimension of 40 mm by 55 mm. Fabricated antenna shows frequency bands of 2.33-2.75 GHz and 4.38-7.5 GHz for a voltage standing wave ratio less than 2. Measured gain remains more than 4 dBi in both bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.769-776
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• 2002

In this paper, we propose uniform slot width bow-tie-shaped meander slot antenna for 5 GHz application. The conventional bow-tie slot antenna has broadband characteristic, however, its size is large. Meanwhile, the meander slot antenna has small size, but it has quite narrow bandwidth. The proposed antenna geometry is a variation of the meander slot antenna incorporating bow-tie shape to realize miniaturized antenna having relatively large bandwidth. Simulated results show that with the same slot width and total slot length, the bandwidth of the proposed antenna is 3 times wider than that of meander slot antenna, and its resonant frequency is 3.01 GHz lower than that of the equal size(H x V) bow-tie slot antenna, and measured results show that the bandwidth of proposed antenna is 218 MHz(5.142 GHz ~ 5.360 GHz) which satisfy the required bandwidth from 5.15 GHz to 5.35 GHz.

• ETRI Journal
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• v.34 no.5
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• pp.674-683
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• 2012

We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular-ring-shaped tuning stub that can be deployed in ultra-wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band-notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L- and J-shaped parasitic elements. The antenna characteristics can be modified to tune the band-notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L- and J-shaped parasitic elements also provide the band-rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.63-70
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• 2001

We demonstrate the MMIC (monolithic microwave integrated circuit) frequency doublers generating stable and low-cost 29 GHz local oscillator signals from 14.5 GHz input signals. These devices were designed and fabricated by using the M MIC integration process of $0.1\;{\mu}m$ gate-length PHEMTs (pseudomorphic high electron mobility transistors) and passive components. The measurements showed S11 or -9.2 dB at 145 GHz, S22 of -18.6 dG at 29 GHz and a minimum conversion loss of 18.2 dB at 14.5 GHz with an input power or 6 dBm. Fundamental signal of 14.5 GHz were suppressed below 15.2 dBe compared to the second harmonic signal at the output port, and the isolation characteristics of fundamental signal between the input and the output port were maintained above :i0 dB in the frequency range 10.5 GHz to 18.5 GHz. The chip size of the fabricated MMIC frequency doubler is $1.5{\times}2.2\;mm^2$.