• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.215-220
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• 2016

In this paper, a wideband antenna accomplished by adding a double sleeve of a rectangular planar monopole structure is proposed. In order to impedance matching of proposed antenna, the antenna performance was improved by adding two gap sleeves and outer sleeve for double sleeve structure. HFSS simulator of ANSYS corp. was used in order to confirm the antenna parameter characteristic. According to the simulation results, the VSWR was less than 2 for the range of 2.5GHz~10.5GHz. The frequency bandwidth is 8GHz. The frequency range of the actual fabricated antenna was 2.92GHz~10.32GHz, the frequency bandwidth is 7.4GHz. The measured radiation pattern frequency is 3GHz, 6GHz and 9GHz. The results are similar with dipole antenna pattern in all frequency. The antenna size is $40{\times}40mm^2$. The utilization possibility of the ultra-wideband planar monopole antenna could be confirmed according to compare and analyze the simulation and measurement data.

• ETRI Journal
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• v.32 no.5
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• pp.827-830
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• 2010

For an adaptive cruise control (ACC) stop-and-go system in automotive applications, three radar sensors are needed because two 24 GHz short range radars are used for object detection in an adjacent lane, and one 77 GHz long-range radar is used for object detection in the center lane. In this letter, we propose a single sensor-based 24 GHz radar with a detection capability of up to 150 m and ${\pm}30^{\circ}$ for an ACC stop-and-go system. The developed radar is highly integrated with a high gain patch antenna, four channel receivers with GaAs RF ICs, and back-end processing board with subspace based digital beam forming algorithm.

• Progress in Superconductivity
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• v.2 no.1
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• pp.51-55
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• 2000

A $Y_1Ba_2Cu_3O_{7-\delta}$ square spiral microstrip antenna (YBCO antenna) was epitaxially grown on a $LaAlO_3$ substrate by laser ablation. Also fabricated was a gold square spiral microstrip antenna (gold antenna) having the same structure as that of the YBCO antenna in order to compare the properties of both antennas. Both the YBCO antenna and the gold antenna were operated in Ku (12-18 GHz) band, and their properties such as the return loss, SWR, power gain, and radiation patterns were investigated at 77 K. The return loss below -10 dB was obtained in two frequency ranges, i.e., 14.05-14.90 GHz, and 16-18 GHz for the YBCO antenna at 77 K (YBCO superconducting antenna), and in the frequency range of 15.05-17.60 GHz for the gold antenna at 77 K. The SWR bandwidths are 0.85 GHz and 2 GHz for the YBCO superconducting antenna, and 2.55 GHz for the gold antenna at 77 K. The gain improvement of the superconducting YBCO antenna over the gold antenna at 77 K was about 10 dB in the frequency range of 16 GHz to 18 GHz. The radiation patterns show the YBCO superconducting antenna has the omni-directional property of a spiral antenna.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.501-503
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• 2008

This paper presents the design of a 2.4 GHz low phase noise fully integrated LC Voltage-Controlled-Oscillator (VCO) in $0.18{\mu}m$ CMOS technology. The VCO is without any tail bias current sources for a low phase noise and, in which differential varactors are adopted for the symmetry of the circuit. At the same time, the use of differential varactors pairs reduces the tuning range, i.e., the frequency range versus VTUNE, so that the phase noise becomes lower. The simulation results show the achieved phase noise of -138.5 dBc/Hz at 3 MHz offset, while the VCO core draws 3.9mA of current from a 1.8V supply. The tuning range is from 2.28GHz to 2.55 GHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.34-41
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• 2011

This paper presents a wide tuning range, fine-resolution DCO (Digitally Controlled Oscillator) with an active inductor. In order to control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. To cover the wide tuning range, an automatic three-step coarse tuning scheme is proposed. The DCO total frequency tuning range is 1.4 GHz (2.1 GHz to 3.5 GHz), it is 58 % at 2.4 GHz. An effective frequency resolution is 0.14 kHz/LSB. The proposed DCO is implemented in 0.13 ${\mu}m$ CMOS process. The total power consumption is 6.6 mW from a 1.2 V supply voltage. The phase noise of the DCO output at 2.4 GHz is -120.67 dBc/Hz at 1 MHz offset.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1075-1080
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• 2021

In this paper, we designed a 24.4GHz 2-channel TX and 4-channel RX patch array antenna mounted on a short-range vehicle radar system to simultaneously measure the range and speed of a single object within a single measurement cycle. The antenna was designed and fabricated using Rogers' RO4350B(ε_r=3.48, 0.5T) board. Through measurement, it was confirmed that the design specifications of antenna gain (> 10dBi or more) and radiation pattern (Elevation HPBW > 10deg.) were satisfied at 24.4 GHz frequency.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.621-624
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• 2003

In this paper, two Cascode Low Noise Variable Gain Amplifiers are proposed for wide dynamic range and constant Noise Figure for frequency range of 2.4GHz. Designed Variable Gain Low Noise Amplifier are for Wireless Local Area Network (WLAN) applications. A gain is higher than 17dB and the noise figure is approximately 1.3dB and the input VSWR is better than 2:1.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.453-458
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• 2010

In this work, a 18 GHz divide-by-4 injection-locked frequency divider(ILFD) based on ring oscillator has been developed in $0.13-{\mu}m$ Si RFCMOS technology. The free-running oscillation frequency is from 4.98 to 5.22 GHz and output power is about －30 dBm, consuming 33.4 mW with a 1.5 V supply voltage. At 0 dBm input power, the locking range is 3.5 GHz(17.75~21.25 GHz) and with varactor tuning, the operating range is increased up to 5.25 GHz(16.0~21.25 GHz). The fabricated chip size is $0.76\;mm{\times}0.57\;mm$ including DC and RF pad.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.64-72
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• 2010

This paper presents a wide range VCO with fine coarse tuning step using a sigma-delta modulation technique for UWB frequency synthesizer. The proposed coarse tuning scheme provides the low effective frequency resolution without any degradation of phase noise performance. With three steps coarse tuning, the VCO has wide tuning range and fine tuning step simultaneously. The frequency synthesizer with VCO was implemented with 0.13 ${\mu}m$ CMOS technology. The tuning range of the VCO is 5.8 GHz~6.8 GHz with the effective frequency resolution of 3.9 kHz. It achieves the measured phase noise of -108 dBc/Hz at 1 MHz offset and a tuning range 16.8 % with 5.9 mW power. The figure-of-merit with the tuning range is -181.5 dBc/Hz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.227-229
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• 2002

In this paper, we report on a microstrip line voltage controlled tunable bandpass filter. We used the characteristic the relative dielectric constant of thin film ferroelectrics depends on the applied dr voltage. we designed using Au/BSTO/MgO/Au structure. We cascaded many resonators for large furling range sustaining 1 GHz renter frequency, narrow band, low IL ($\leq$4 dB). We could design the BPF of which center frequency is 16 GHz, 1.9 GHz tuning range, the narrow bandwidth within 800 MHz, low insertion loss less than 3 dB by adjusting the gap of 3 cascaded resonators.