• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.33-38
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• 2013

In this paper, we present the design and measured performances of an dual-band Gysel power divider based on band-stop characteristic. After the Gysel divider is designed by lumped elements at single operating frequency, and then using filter conversion technique the lumped elements were changed a band-stop characteristic with dual-band characteristics. The features of this design method are that ${\lambda}/4$ transmission line by replacing lumped elements suppressed harmonic characteristics and also can reduce the size. To validate of the proposed power divider, the divider has been designed and measured at 880 MHz and 1650 MHz dual frequencies. The measured performances of the Gysel divider agree with prediction results at two frequencies.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.31-37
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• 2010

In this paper, highly efficient dual-band class-F power amplifiers(PAs) for cellular and WLAN bands are suggested and implemented. For the first step, single-band class-F amplifiers at 840MHz, 2.4GHz are designed using commercial E-pHEMT FETs. The performance of two single band PAs are as much as 81.2% of efficiency with the output power of 24.4dBm with 840MHz PA and 93.5% of efficiency with 22.4dBm from the 2.4GHz. For the dual-band class-F PA, the harmonic controlling circuit with ideal SPDT switch was suggested. The length of transmission line is variable by a SPDT switch. As a results, the operation in 840MHz showed the peak efficiency of 60.5% with 23.5dBm, while in 2.4GHz mode the efficiency was 50.9% with the output power of 19.62dBm. Besides, it is shown that the harmonic controller of class-F above 2Ghz could be implemented on the low cost FR-4 substrate.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.411-416
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• 2008

When compose magnetic field curer by belt and band style and need by magnetic field ripple last month, produce self-discipline roof. Bred in muscle disease (lumbago, backbone disease, corpulence) back. Result that study, manufactured various variableness band style - magnetic field probe firstly. Can establish self-discipline treatment pulse price by disease secondly. Could seek correct variableness band punishment, - magnetic field probe relationship implementation and property in waist, and so on, shoulder, neck, arm, leg, ankle, wrist etc. by third. Could find variableness band style energy value that need in-magnetic field Probe's treatment by fourth. This research could design pulse of self-discipline in band form and apply each according to disease.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.837-843
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• 2008

This paper proposes a power divider based on meta-material structure with dual-band operation. The meta-material structures of left-hand characteristic are constituted of series capacitors and shunt inductors, but they have parasitic series inductance and shunt capacitance effects. There is represented the composite right/ left-handed transmission line (CRLH-TL) model. When the power divider is implemented by using the CRLH-TL, the power divider can operate dual band. To verify the power divider with dual band, we are implemented to operate dual-band that is 0.88 GHz and 1.67 GHz. The characteristics of divider have the return loss less than each 21.0 dB and 15.8 dB and the insertion loss better than 3.83 dB and 3.64 dB at each frequency. Also, the output phase difference is $3{\sim}6^{\circ}$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.4
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• pp.501-505
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• 2015

In this paper, we demonstrated a 4W power amplifier monolithic microwave integrated circuit (MMIC) for Ku-band satellite communication applications. The used device technology relies on $0.25{\mu}m$ GaAs pseudomorphic high electron mobility transistor (PHEMT) process. The 4W power amplifier MMIC has linear gain of over 30 dB and saturated output power of over 36.1 dBm in the frequency range of 13.75 GHz ~ 14.5 GHz. Power added efficiency (PAE) is over 30 %.

• ETRI Journal
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• v.29 no.4
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• pp.536-538
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• 2007

We propose and describe the fabrication of a linear power amplifier (LPA) using a new analog feedforward method for the IMT-2000 frequency band (2,110-2,170 MHz). The proposed analog feedforward circuit, which operates without a pilot tone or a microprocessor, is a small and simple structure. When the output power of the fabricated LPA is about 44 dBm for a two-tone input signal in the IMT-2000 frequency band, the magnitude of the intermodulation signals is below -60 dBc and the power efficiency is about 7%. In comparison to the fabricated main amplifier, the magnitude of the third intermodulation signal decreases over 24 dB in the IMT-2000 frequency band.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.3
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• pp.438-445
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• 2017

This paper presents a low-power high-resolution band-pass ${\Sigma}{\Delta}$ ADC for accelerometer applications. The proposed band-pass ${\Sigma}{\Delta}$ ADC consists of a high-performance 6-th order feed-forward ${\Sigma}{\Delta}$ modulator with 1-bit quantization and a low-power, area-efficient digital filter. The ADC is fabricated in 180 nm 1P6M mixed-signal CMOS process with a die area of $5mm^2$. This high-resolution ADC got 90 dB peak signal to noise plus distortion ratio (SNDR) and 96 dB dynamic range (DR) over 4 kHz bandwidth, while the intermediate frequency (IF) is shifting from 100 KHz to 200 KHz. The power dissipation of the chip is 5.6 mW under 1.8 V (digital)/3.3 V (analog) power supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.788-793
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• 2004

This paper proposes new configuration for the dual power amplifier that operates at 5.8 GHz for the wireless LAN and 1.8 GHz for the PCS. It dose not select the input signal but amplify the dual band signals simultaneously. Broadband diplexer is used at the input to separate the dual band signals. Output power of each amplifier is 1 W. The PBG is employed to improve the performance of power amplifier. Generally, the PBG is employed at the end of output matching network. But in this paper, the PBG is employed in the load pull output matching circuit of amplifer to maximize the output power.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.6
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• pp.540-545
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• 2015

This paper presents the design, fabrication and measurement results of a S-band internally-matched power amplifier using Gallium Nitride High Electron Mobility Transistor(GaN HEMT) die. In order to fabricate the S-band internally-matched power amplifier, a high dielectric substrate and alumina were used for input/output matching circuits. The measured output power is 55.4 dBm, the drain efficiency is 78 % and the power gain is 11 dB under pulse operation at the frequency of 3 GHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2194-2200
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• 2010

In this paper, the power detectors using metamaterials were designed and fabricated for multi-band six-port direct conversion method. The RF short-stubs for power detector were designed by using metamaterials which provide multi-band characteristics. The power detectors with metamaterial RF short-stub were analyzed and fabricated by using lumped and distributed element. The measured results of metamaterial power detectors show the good agreement with the simulation results. The performance of lumped-metamaterial RF short-stub shows the insertion loss below 1 dB and the good frequency response characteristics. Also, the distributed-metamaterial RF short-stub shows the good frequency response characteristics and the insertion loss under that of lumped-metamaterial RF short-stub. The multi-band power detectors with metamaterial RF short-stub detect the input RF signal in the designed dual frequency bands very well.