• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.87-94
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• 2006

For realizing an ubiquitous home network(uHome-net), various sensors should be able to be connected to an integrated wire/wireless sensor network. This paper describes an application case of applying LonWorks technology being widely used in control network to wire/wireless sensor network in uHome-net and the design and application of LonRF device that consists of a neuron chip including LonTalk protocol, a 433.92MHz RF transceiver, a sensor, and application programs. As an application example of the LonRF device, the LonRF smart badge that can measure the 3D location of objects in indoor environment and interwork with the uHome-net was developed. LonRF device based home network services were realized on the uHome-net testbed such as indoor positioning service, remote surveillance service and remote metering service were realized. This research shows that LonWorks technology based sensor network could be applicable to the control network in an ubiquitous home network and the LonRF device can be used as a wireless node in various sensor networks.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.566-573
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• 2004

This paper describes the ubiquitous home network (uHome-net) testbed and LonRF intelligent devices based on LonWorks technology. These devices consist of Neuron Chip, RF transceiver, sensor, and other peripheral components. Using LonRF devices, a home control network can be simplified and most devices can be operated on LonWorks control network. Also, Indoor Positioning System (IPS) that can serve various location based services was implemented in uHome-net. Smart Badge of IPS, that is a special LonRF device, can measure the 3D location of objects in the indoor environment. In the uHome-net testbed, remote control service, cooking help service, wireless remote metering service, baby monitoring service and security ＆ fire prevention service were realized. This research shows the vision of the ubiquitous home network that will be emerged in the near future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.2
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• pp.304-309
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• 2019

This paper presents a CMOS RF-to-DC converter for video surveillance disposable IoT applications. It widely harvests RF energy of 3G/4G cellular low-band frequency range by employing a tunable impedance matching network. The proposed converter consists of the differential-drive cross-coupled rectifier and the matching network with a 4-bit capacitor array. The proposed converter is designed using 130-nm standard CMOS process. The designed energy harvester can rectify the RF signals from 700 MHz to 900 MHz. It has a peak RF-to-DC conversion efficiency of 72.25%, 64.97%, and 66.28% at 700 MHz, 800 MHz, and 900 MHz with a load resistance of 10kΩ, respectively.

• ETRI Journal
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• v.29 no.3
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• pp.371-380
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• 2007

This paper proposes a new automatic compensation network (ACN) for a system-on-chip (SoC) transceiver. We built a 5 GHz low noise amplifier (LNA) with an on-chip ACN using 0.18 ${\mu}m$ SiGe technology. This network is extremely useful for today's radio frequency (RF) integrated circuit devices in a complete RF transceiver environment. The network comprises an RF design-for-testability (DFT) circuit, capacitor mirror banks, and a digital signal processor. The RF DFT circuit consists of a test amplifier and RF peak detectors. The RF DFT circuit helps the network to provide DC output voltages, which makes the compensation network automatic. The proposed technique utilizes output DC voltage measurements and these measured values are translated into the LNA specifications such as input impedance, gain, and noise figure using the developed mathematical equations. The ACN automatically adjusts the performance of the 5 GHz LNA with the processor in the SoC transceiver when the LNA goes out of the normal range of operation. The ACN compensates abnormal operation due to unusual thermal variation or unusual process variation. The ACN is simple, inexpensive and suitable for a complete RF transceiver environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.682-684
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• 2007

This paper deals the application of sensor network system to fabricate wireless nodes. This node includes a CPLD(XC2C256), FPGA(XC3S1000) a RF module(Bim-433-F), a Hall Sensor and I also develop the CPLD(EPGA) controlling with Verilog-HDL using ISE. The network was consisst of a PC, a Sink node as a gateway, and three Sensor nodes. This sensor network can reaches 40 m with RF interface using by multi-path network.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.624-630
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• 2006

ZnO deposition parameters are not independent and have a nonlinear and complex property. To propose a method that could verify and predict the relations of process variables, neural network was used. At first, ZnO thin films were deposited by using RF magnetron sputtering process with various conditions. Si, GaAs, and Glass were used as substrates. The temperature, work pressure, and RF power of the substrate were $50\sim500^{\circ}C$, 15 mTorr, and $180\sim210W$, respectively : the purity of the target was ZnO 4 N. Structural properties of ZnO thin films were estimated by using XRD (0002) peak intensity. The structure of neural network was a form of 4-7-1 that have one hidden layer. In training a network, learning rate and momentum were selected as 0.2, 0.6 respectively. A backpropagation neural network were performed with XRD (0002) peak data. After training a network, the temperature of substrate was evaluated as the most important parameter by sensitivity analysis and response surface. As a result, neural network could capture nonlinear and complex relationships between process parameters and predict structural properties of ZnO thin films with a limited set of experiments.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.85-91
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• 2017

This paper concerns the design of a matching module system enabling the RF signal to be harmonized between the new base stations (RRH) and the repeater in the same frequency band of the asynchronous transfer network. This matching system controls the RF Gain Control of the module while monitoring the quality of the quality. Additionally, the RF environment has been adapted accordingly to adjust the RF Gain Control to match the receiver characteristics of the relay. As a result of this study, we improved the quality of the interface between the new base stations and existing relays.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1051-1057
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• 2009

USN(Ubiquitous Sensor Network) is used to provide many services such as bridge monitoring, cultural properties monitoring, river monitoring, protection of an old and feeble person, management and control of a city and circumstance monitoring, etc. A RF transceiver is needed for implementing USN. In this paper the implementation and the design of a RF transceiver for sensor nodes operating in 2.4GHz frequency band are presented. The design procedure of AGC, a receiver and a transmitter is described. And the performance of the implemented RF transceiver is also tested. The test results of receiver sensitivity, receiver dynamic range, frequency stability, phase noise, output power of transmitter, flatness and spectrum mask are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1702-1707
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• 2010

As quantities of the data that transmitting by the wireless are more increased, the interest and application are extending about 802.11n that uses by combination two existing 20MHz wireless LAN Channel. 802.11n use dual band of 2.4GHz band and 5.8GHz. So this is expected in mass wireless transmission method because of interference evasion effect in compliance with the radio communication of existing 2GHz neighborhood band. Like this 802.11n uses the radio as well and transmits information there is not only a possibility of undergoing an influence in radio wave environment of circumference. Specially the interior environment and outdoor environment is a possibility of saying that will be defined with each other different modeling as affects in radio communication is different. In this paper, we'll compare the influence to RF feature (802.11n) by (Indoor/Outdoor) environment difference through compared with 802.11n RF feature and Network feature in (Indoor/Outdoor) environment and also examine the correlation between RF feature and Network feature.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.733-740
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• 2001

A monitoring robot capable of doing network and RF communication is introduced. The robot has several features that poses arbitrary position thanks to a mechanism combining the 4wheel drive and 4 link mechanism, transmits an image and command data via RF wireless communication. Moreover, the image data from the camera are transferred through a network communication. The robot plays a role in monitoring what is happening around the robot, and covers wide range due to a moving camera associated with the 4 arms. The robot can adjust its mass center by the 4 link mechanism, hence it guarantees a stability in moving on the slope.