• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.142-148
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• 2004

We investigated a Ti:LiNbO$_3$ based integrated-optic polarization controller with a Ti-indiffused waveguide along the z-axis utilizing the electro-optic effect. The device consists of a first quarter-wave (λ/4) phase-shifter followed by a half-wave(λ/2) and a second quarter-wave(λ/4) wave-plate, which is rotated synchronously with the first quarter-wave phase-shifter. We analyzed the operation principles of the device utilizing cascaded transfer matrices based on Jones matrix and Poincare sphere, simulated driving voltages for various input states of polarization (SOP), and theoretically confirmed transformations from any arbitrary input SOP into any general output SOP.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.2
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• pp.85-95
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• 2000

This paper describes a sensorless control scheme for brushless dc motors(BLDCMs) using a phase shifter(FIPS) which can shift the zero-crossing point of the input signal with a specified amount of phase. The detection performance of the proposed FIPS is independent of the frequency of the input signal and quite robust with respect to the measurement noise. It is shown that the proposed sensorless control scheme using the FIPS is more effective in the respects of noise-robustness and cost than the previously known schemes. The generality and practicality of the proposed sensorless control scheme is demonstrated through performance analysis and experiments under various operating conditions.

• ETRI Journal
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• v.38 no.3
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• pp.417-424
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• 2016

In this paper, an accurate characterization of a fabricated X-band transmit/receive module is described with the process of generating control data to correct amplitude and phase deviations in an active electronically scanned array antenna unit. In the characterization, quantization errors (from both a digitally controlled attenuator and a phase shifter) are considered using not theoretical values (due to discrete sets of amplitude and phase states) but measured values (of which implementation errors are a part). By using the presented procedure for the characterization, each initial control bit of both the attenuator and the phase shifter is closest to the required value for each array element position. In addition, each compensated control bit for the parasitic cross effect between amplitude and phase control is decided using the same procedure. Reduction of the peak sidelobe level of an array antenna is presented as an example to validate the proposed procedure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1121-1127
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• 2010

This paper describes the equivalent circuit of $45^{\circ}$ layer, one of $11.25^{\circ}$, $22.5^{\circ}$, and $45^{\circ}$ phase shift layers, which are needed for X-band Radant lens 4-bit phase shifter. The equivalent circuit is extracted by comparing the CST's MWS results with the Agilent's ADS results for $45^{\circ}$ phase shift layer. The simulated result is compared with the measured one. Using the extracted equivalent circuit, the phase bit simulation results of 4-bit Radant lens are also presented.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.259-267
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• 1999

In this paper, a C-band 6-bit phase shifter is designed and fabricated and design techniques for each phase bit are represented. We applied the loaded line type to $5.625^{\circ},\;11.25^{\circ},\;22.5^{\circ}\;and\;45^{\circ}$ phase bits and the hybrid coupled type to $90^{\circ}$ phase bit and the switched line type to $180^{\circ}$ phase bit, respectively on a microstrip copper substrate.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.862-865
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• 2007

Rx and Tx signal use same band in RFID. Then RFID system is not used duplexer and used coupler. RFID system have problem about Rx part to Tx leakage signal because that Rx signal port is Tx signal port's Isolation port. We proposal using phase shifter Tx leakage signal decrease than other RFID system. It is same signal Tx signal port's coupling port and isolation port signal except amplitude and phase. So if make coupling signal and isolation signal is in all same signal. We cancel Tx leakage signal used coupling port. And verification about ADS2006.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.904-908
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• 2002

In this paper, we propose a 4-coupled ferroelectric-based meander-type microstrip-line tunable phase shifter which has less than 2dB of insertion loss (IL) and larger than 10dB of return loss (RL)over 13~170Hz .Particularly at 15GHz, the differential phase shift (DPS) is observed to be $89{\circ}$ at zero bias and it increases up to $115{\circ}$ when 150V is applied. This indicates a DPS tunability of $26{\circ}$.

• Journal of IKEEE
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• v.24 no.3
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• pp.895-900
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• 2020

In this paper, BSPE replaced the existing multiplication algorithm that consumes a lot of power. Hardware resources are reduced by using a bit-serial multiplier, and variable integer data is used to reduce memory usage. In addition, MOA resource usage and power usage were reduced by applying LOA (Lower-part OR Approximation) to MOA (Multi Operand Adder) used to add partial sums. Therefore, compared to the existing MBS (Multiplication by Barrel Shifter), hardware resource reduction of 44% and power consumption of 42% were reduced. Also, we propose a hardware architecture design for BSPE Core.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.209-214
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• 2006

The purpose of this study is to improve the stream water quality by the experimental hybrid constructed wetland system. It consisted of the water layer, sand bed planted reeds, irises and roses, gravel bed, yellow-soil media bed and a flow shifter (FS) which can reverse top and bottom flow in the middle of the wetland. The organic compounds and nitrogen removal efficiencies varied with the seasons, namely temperature change. In summer, the mean efficiencies of COD and TN in the outflow from this wetland system were 63.4 and 48.0% and shown the highest, respectively, whereas, the suspended solids and phosphorus removal efficiencies seemed to be less affected by temperature. As a result of inspecting the decreasing trend of pollutants, nitrification-denitrification in the wetland was the major removal mechanism for nitrogen, the nitrogen reduction was especially enhanced by the application of a FS in the wetland, and phosphorus reduction was mainly occurred as a consequence of adsorption of the yellow-soil media.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.611-616
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• 2006

In this paper, we propose a practical implementation method of a soft bit decision expression for an R-QAM (Gray coded Rectangular Quadrature Amplitude Modulation) signal based on the Max-Log-MAP algorithm. The parameters of the soft decision expression for the practical implementation can be obtained with simple arithmetic functions associated with some deterministic parameters such as a received value, distances between symbols, and the order of modulation on a signal space. Also, we analyze the performance of an iterative decoding scheme for the QAM signal with I/Q phase unbalance. The unbalance results from the non-ideal characteristic of components such as a phase shifter between in-phase and quadrature paths for quadrature modulator/demondulator.