• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.52-58
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• 2008

Ths paper describes the Dual-band switch which was proposed new structure that could improved the specification of broadband and designed by the optimized structure through simulation. The Dual-band switch with 2.4[GHz]/5.8[GHz] that can apply to 802.11a/b/g system that is commercialized present was studied to get a new structure with higher power, high isolation. The transmitter of switch was designed to operate a parallel switching element with stack structure of two FET. The receiver designed to have asymmetry structure that insert series FET in addition to basic serial/parallel FET. SPDT(Single Pole Double Throw) Tx/Rx FET switch is a device that can do switching from a port of input to two port of output. The fabricated SPDT switch has the characteristic of insertion loss of a below -3[dB] form DC to 6[GHz] and the isolation of a below -30D[dB](Rx mode).

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2039-2040
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• 2006

Persistent current switch (PCS) system in NMR, MRI, MAGLEV and SMES has many advantages, such as uniformity and durability of magnetic field and reducing a thermal loss, which enable many superconducting application to operate effectively. This paper deals with fabrication and test of heater trigger persistent current switch using coated conductor (CC) which has high n-index, critical current independency from external magnetic field and adaptable selectivity of stabilizer. PCS system consists of magnet power supply for energizing current to a magnet, heater, switch and magnet using coated conductor tape. Finite element method (FEM) is used to simulate thermal quench (switching) characteristic and design heater trigger. With FEM simulation, optimal length of heater is calculated by temperature and time analysis. Fabrication of PCS system and test of heater trigger characteristic were performed and compared with simulation result. This paper would be the foundation of researches of superconducting switching application.

• Korean Journal of Materials Research
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• v.12 no.4
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• pp.254-258
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• 2002

To realize channel cross-connecting in optical communications systems, a high speed optical matrix switch was fabricated using z-cut $LiNbO_3$. For switch fabrication was design bending structure and coupling length and four $2{\times}2$ directional couplers were integrated on one substrate far construction of a $4{\times}4$ switch. Single-mode optical waveguides were formed by Ti-diffusion at a wet $O_2$ atmosphere. Ti-diffusion profile, refractive index variation and waveguide morphology were analyzed by Prism coupler and optical microscopy, respectively.

• ETRI Journal
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• v.30 no.4
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• pp.526-534
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• 2008

This paper presents a fully integrated 0.13 ${\mu}m$ CMOS MB-OFDM UWB transmitter chain (mode 1). The proposed transmitter consists of a low-pass filter, a variable gain amplifier, a voltage-to-current converter, an I/Q up-mixer, a differential-to-single-ended converter, a driver amplifier, and a transmit/receive (T/R) switch. The proposed T/R switch shows an insertion loss of less than 1.5 dB and a Tx/Rx port isolation of more than 27 dB over a 3 GHz to 5 GHz frequency range. All RF/analog circuits have been designed to achieve high linearity and wide bandwidth. The proposed transmitter is implemented using IBM 0.13 ${\mu}m$ CMOS technology. The fabricated transmitter shows a -3 dB bandwidth of 550 MHz at each sub-band center frequency with gain flatness less than 1.5 dB. It also shows a power gain of 0.5 dB, a maximum output power level of 0 dBm, and output IP3 of +9.3 dBm. It consumes a total of 54 mA from a 1.5 V supply.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.794-797
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• 2005

The automatic load transfer switch (ALTS), a kind of electric power switch, typically automatically transfers electrical loads from a normal electrical power source to an emergency electrical power source upon reduction or loss of normal power source voltage. It can also automatically re-transfer the load to the normal power source when the normal voltage has been restored within acceptable limits. The transfer operation of ALTS is accomplished by a spring-driven linkage mechanism. In order to control or delay the transfer switching time, the ALTS studied in this paper uses the superposed leaf springs, which are subjected to impact leadings in contacting with electrical contacts. Therefore, to confirm whether the springs has enough mechanical endurance in ALTS, we build a finite element model of the superposed lear springs using LS-DYNA and perform the impact and fatigue analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.855-869
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• 1997

In this paper, we proposed two kids of dynamic priority control mechanisms controlling the cell service ratio in order to improve the QOS(Quality of Service). We also analyse theoretically the characteristics of cell loss probability and mean cell delay time by applying the proposed priority control mechanisms to ATM switch with output buffer. The proposed priority control mechanisms have the same principles of storing cells into buffer but the different principles of serving cells from buffer. The one is the control mechanism controlling the cell service ratio according to the relative cell occupancy ratio of buffer, the other is the control mechanism controlling the cell service ratio according to both the relative cell occupancy ratio of buffer and the average arrival rate. The two service classes of our concern are the delay sensitive class and the loss sensitive class. The analytical results show that the proposed control mechanisms are able to improve the QOS, the characteristics of cell loss probability and mean cell delay time, by selecting properly the relative cell occupancy ratio of buffer and the average arrival rate. conventional DLB algorithm does not support synchronous cells, but the proposed algorithm gives higher priority to synchronous cells. To reduce synchronous cell loss rate, the synchronous cell detector is used in the proposed algorithm. Synchronous cell detector detects synchronous cells, and passes them cells to the 2nd Leaky-Bucket. So it is similar to give higher priority to synchronous cells. In this paper, the proposed algorithm used audio/video traffic modeled by On/Off and Two-state MMPP, and simulated by SLAM II package. As simulation results, the proposed algorithm gets lower synchronous cell loss rate than the conventional DLB algorithms. The improved DLB algorithm for multimedia synchronization can be extended to any other cells which require higher priority.

• Journal of IKEEE
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• v.14 no.3
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• pp.232-235
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• 2010

A 60GHz active phase shifter with 65nm CMOS is presented by replacing passive switches in switched-line type phase shifter with active ones. Active-switch phase shifter is composed of active-switch blocks and passive delay network blocks. The active-switch phase shifter design is compact compare with the conventional vector-sum phase shifter. Active-switch blocks are designed to accomplish required input and output impedances whose requirements are different whether the switch is on or off. And passive delay network blocks are composed of lumped L,C instead of normal microstrip line to reduce the size of the circuit. An 1-bit phase shifter is fabricated by TSMC 65nm CMOS technology and measurement results present -4dB average insertion loss and 120 degree phase shift at 65GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.1-7
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• 2016

In this paper, the tunable filter based on high power cavity using mechanical switch for 1.5 GHz band is presented. The LPF is inserted to eliminate the spurious wave, coupler is embeded to extract the output power, and then the tunable filter system is configured using mechanical switch. The LPF obtains attenuation over 40 dB between 4 GHz and 12.75 GHz, Coupler is satisfied with coupling value 40 dB and coupling isolation over 55 dB. The tunable filter system using mechanical switch obtains insertion loss 0.88 dB at bypass mode between 1,495.9 MHz and 1,510. 9 MHz, 3.29 dB at fil mode between 1,495.9 MHz and 1,500.9 MHz. It is also satisfied with output power of 132 W at the center frequency 1,498.4 MHz, and switching time below 10 ms.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.223-229
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• 2023

This papart proposes single pole double throw (SPDT) switch with six-stage radial stub resonators in the 3.6~4.0 GHz band. The switch was simulated using ADS (Advanced Design Software), a design tool for the wireless communication circuits, and evaluated on a pcb substrate. The measurement results of the radial SPDT switch showed an average 90 dB isolation, and 1.5 dB insertion loss. This isolation characteristic was 20 dB superior to higher than those laboratory or commercial products reported thus far. The proposed SPDT switch is applicable to multi-band RF front-end systems, such as WiMAX, LTE/5G, Wi-Fi, and HyperLAN.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.339-342
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• 1998

The various services that a broadband integrated services digital network (B-ISDN) carries, have a wide range of delay, delay jitter and cell loss probability requirements. Design of appropriate control schemes for B-ISDN is an extremely important and challenging problem. In this paper, we proposes a priority control scheme with a delay counter and a cell counter per each class type. The priority control for required service quality is performed with delay/loss factor obstained by comparing window counter with cell counter. The performance of proposed control scheme is estimated by computer simulation.