• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.104-110
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• 2003

This paper proposed a simple 180$^{\circ}$ MMIC phase shifter for wideband application. The phase shifter simply consists of a Lange coupler and two GaAs PIN diodes. The measured performance of the phase shifter in the 2 to 6 GHz band shows a maximum phase error of less than 13$^{\circ}$, maximum 3.2 dB insertion loss, and minimum 6.3 dB return loss.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.296-303
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• 2003

In this paper, a design method is proposed for the reflection type phase shifter applied to the DTV(Digital TV) receiver, and a phase shifter is designed by using the design equations to satisfy the phase shifting range over 180 degrees for frequency range from 470 MHz to 860 MHz, the receiving band of DTV. From the proposed method, it is possible that the systematic design of the reflection type phase shifter with desired phase shifting range and insertion loss. In addition, it is found that the realized phase shifter satisfies the given specifications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.768-771
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• 2003

Nowadays, the study on the ceramic components and modules used in telecommunication system is being performed. Duplexer is the one of the most important components and has the role of dividing Rx and Tx signal. Duplexer including the FBAR is being done vigorously LTCC is used for package like SAW package, duplexer package. In our research, LTCC material is used for FBAR duplexer package and photo-lithography for the fine line phase shifter. The good characteristics, low loss and good isolation, of duplexer is obtained by the fine line phase shifter having high characteristic impedance of stripline.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.21-24
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• 2000

This paper introduces the design and implementation of a Ku-band 5-bit monolithic phase shifter with a ceramic package. The 5-bit phase shifter MMIC was designed and fabricated by using GaAs MESFET switches. The packaged phase shifter demonstrates a phase error less than 11.3 $^{\circ}$ RMS and an insertion loss variation less than 1.0㏈ RMS for 13∼15㎓. For all 32 states, an insertion loss is measured to be 12.2${\pm}$2.2㏈, an input return loss more than 5.0㏈, and an output return loss more than 6.2㏈ from 13㎓ to 15㎓. The chip size of the 5-bit phase shifter MMIC is 2.35${\times}$1.65mm$\^$2/ including digital control circuits. The size of the ceramic packaged phase shifter is 7.2${\times}$6.2mm$\^$2/.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1745-1752
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• 2009

This Paper represents a new method, which uses defected ground structure (DGS) on the ground planes of microstrip lines, to reduce the size of the Schiffman phase shifter. DGS on the microstrip line shows an increased slow-wave effect due to the additional equivalent L and C components. So the electrical length of transmission line with DGS is longer than that of standard transmission line for the same physical length. Then, the length of transmission line with DGS can be shortened in order to maintain the original electrical length to be same. The performances of reduced phase shifter with DGS are quite similar to the ones of original Schiffman phase shifters. We can reduce the size about 15% using the DGS in original Schiffman phase shifter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.43-52
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• 1996

Nonreciprocal twin-toroid ferrite phase shifter is designed, fabricated, and tested. ABCD matrix method is used to design the phase shifter and to compute its optimum dimen- sions. Quarter-wave two-section impedance matching transformers are utilized in order to match the impedance of the empty guide to that of the ferrite-loaded guide. Driving circuit controls the current needed to drive the phase shifter. Measured insertion loss and VSWR characteristics within the operaring band(9.1GHz ~ 9.5GHz) are less than 1.2dB and 1.15, respectively. After temperature compensation technique is appied to the phase shifter, the measured phase error of the phase shifter is less than $\pm4$ between $-10^{\circ}C\;and\;+60^{\circ}C$.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.39-44
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• 2013

In this paper digital phase-shifter for multi-arm spiral antennas was designed by using Hilbert transform. All frequency components in input signal are phase-shifted for 90 degree by Hilbert transform, and the transform is implemented by FIT and IFIT. Digital phase-shifter generates two signals with phase difference of 90 degree by using Hilbert transform from input signals sampled by analog-digital converter(ADC), and then the input signal is phase-shifted for a given phase by using two signals. Hilbert transform based on digital phase-shifter is designed by Xilinx System generator, and the effects of input noise, FIT point, sampling period, initial phase of input signal, and shifted phase are simulated and its results are compared with Matlab results.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.9
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• pp.49-57
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• 2009

In this paper, we propose a multiple voltage scheduling method which reduces energy consumption considering both timing constraints and resource constraints. In the other multiple voltage scheduling techniques, high voltage is assigned to operations in the longest path and low voltage is assigned to operations that are not on the longest path. However, in those methods, voltages are assigned to specific operations restrictively. We use a simulated annealing technique, in which several voltages are assigned to specific operations flexibly regardless of whether they are on the longest path. In this paper, a post processing algorithm is proposed to further reduce the energy consumption. In some cases, designers may want to reduce the level shifters. To make tradeoff between the total energy and the number (or energy) of level shifters weighted term can be added to the cost function. When the level shifter energy is weighted six times, for example, the number of level shifters is reduced by about 24% and their energy consumption is reduced by about 20%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.907-915
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• 2002

In this paper, a compact digital phase shifter to be used an active phased array antenna system for satellite communications was proposed. The even and odd mode analysis for a given reflection-type phase shifter, which uses a folded hybrid coupler as a base element, was performed and the design parameters were derived. Also, to verify experimentally the electrical performances of the proposed structure, X-band 4-bit digital phase shifter was designed and fabricated using Teflon soft substrate $({\varepsilon}_r; =\;2.17)$. Its circuit size was less than 3.5 cm $\times$ 3.0 cm, and it exhibited at least 50 % size reduction as compared with the conventional unfolded configuration. The experimental results of the fabricated phase shifter showed that the average insertion loss and insertion loss variation were less than 3.5 dB, $\pm$ 0.6 dB within the operating band, 7.9 ~ 8.4 GHz, respectively. And, input and output return loss were more than 10 dB, respectively. Also, the phase response of the phase shifter showed 4-bit operation with $\pm$3$^{\circ}$ rms phase error.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.3
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• pp.158-164
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• 2002

2-6 GHz digital phase shifter module has been designed and fabricated. For the broadband operation and performance, MMIC phase shifter chip for phase shifter module was designed and fabricated by using the reflection-type circuits with Lange coupler. The fabricated phase shifter module shows 6.1$^{\circ}$RMS phase error, 13.5 dB maximum insertion loss, and 8 dB and 10 dB input and output return losses, respectively. Computer controlled measurement systems are realized in order to get the measured data of 32 phase states. The RMS insertion phase error and the average insertion loss deviation among 8${\times}$8 modules for the phased-array system are less than ${\pm}$0.5$^{\circ}$and ${\pm}$0.5 dB, respectively. The size of fabricated phase shifter module is 45 ${\times}$ 22.5 ${\times}$60㎣.