• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.8
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• pp.709-716
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• 2016

In this paper, A duplexer module with temperature-insensitive electrical characteristics was proposed for remote wireless communication system. Duplexer modules are required to have performances of low insertion loss, high isolation between transmitted band and received band, harmonic suppression as well as high power durability in the system for transmitting guided information to missile flying a free space on the ground. The proposed duplexer module are consist of transmission bandpass filter and receiving bandpass filter which are connected to common antenna port, planar coupler for output power monitoring and low pass filter for harmonic attenuation of power amplifier and coaxial cavity resonator. The material and dimensions of the resonator are determined for minimum frequency shift by temperature variation using 3D EM simulation. The measured results of the prototype showed a good agreement with the simulation results, and it should be well applied not only for guided weapon systems but also for any other communication systems such as remote radio head.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1505-1512
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• 2007

The RFID Technology (which is importantly used at the Ubiquitous environment) is attached to all of the units like the ID cards and then information on the units and units' environment is transferred and processed through the radio frequency. so it is the no touched recognition system. RFID Technology's research of the middle ware and wireless interface etc. is currently conducted and variously broaden like the industry of the distribution and logistics. This paper suggests that the gate control system which is based on RFID middle ware is realized to prevent the district and facility for security. The indication of this paper is that algorithm (which is to certificate Users' enterance through RFID EPC code) is proposed and realizes the user certification module, the control module of the gates' opening and closing, the maintenance module of the gate, the display module of coming and going information, test program ect. through RFID technology.

• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.253-257
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• 2011

This study was carried out to solve problems such as radio frequency band depletion, confusion risk, and security loss in existing visible wireless communication systems, and to determine the applicability of next-generation networks. A light-emitting diode (LED) light communication system was implemented with a controlling switching light module using the ATmega16 micro-controller. To solve the existing modulation effect and disturbance in visible light communication, an integrated interface was evaluated with a driving light module and analyzes its reception property. A transmitter/receiver using the ATmel's micro-controller, high-intensity white LED-6 modules, and infrared sensor KSM60WLM and visible sensor TSL250RD were designed. An experiment from the initial value of distance to 2.5 m showed 0.46 V of the voltage loss, and if in long distance, external light interference occurred and light intensity was lost by external impact and thus data had to be modified or reset repeatedly. Additionally, when we used 6 modules through the remote controller's lighting dimming, data could be transmitted up to 1.76 m without any errors during the day and up to 2.29 m at night with around 2~3% communication error. If a special optical filter can reduce as much external light as possible in the integrated interface, the LED for lighting communication systems may be applied in next generation networks.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.10
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• pp.687-698
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• 2001

This paper presents a three dimensional stacked pad area away (PAA) package configuration as an implementation method of radio frequency (RF) circuits. 224MHz RF circuits of intelligence traffic system(ITS) were constructed with the stacked PAA RF pakage configuration. In the process of manufacturing the stacked PAA RF pakage, RF circuits were partitioned to subareas following their function and operating frequency. Each area of circuits separated to each subunits. The operating characteristics of RF PAA package module and the electrical properties of each subunits were examined. The measurement of electrical parameters for solder balls which were interconnects for stacked PAA RF packages showed that the parasitic capacitance and inductance were 30fF and 120pH, respectively, which might be negligible in PAA RF packaging system. HP 4396B network/spectrum analyzer revealed that the amplification gain of a receiver and transmitter at 224 MHz was 22dB and 27dB, respectively. The gain was 3dB lower than designed values. The difference was probably generated from fabrication process of the circuits by employing commercial standard

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.315-333
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• 2021

Due to the Global Navigation Satellite System (GNSS) modernization, recently launched GNSS satellites transmit signals at various frequency bands such as L1, L2 and L5. Considering the Korean Positioning System (KPS) signal and other GNSS augmentation signals in the future, there is a high probability of applying more complex communication techniques to the new GNSS signals. For the reason, GNSS receivers based on flexible Software Defined Radio (SDR) concept needs to be developed to evaluate various experimental communication techniques by accessing each signal processing module in detail. This paper proposes a novel SDR-based A-GNSS receiver capable of processing multi-GNSS/RNSS signals at multi-frequency bands. Due to the modular structure, the proposed receiver has high flexibility and expandability. For real-time implementation, A-GNSS server software is designed to provide immediate delivery of satellite ephemeris data on demand. Due to the sampling bandwidth limitation of RF front-ends, multiple SDRs are considered to process the multi-GNSS/RNSS multi-frequency signals simultaneously. To avoid the overflow problem of sampled RF data, an efficient memory buffer management strategy was considered. To collect and process the multi-GNSS/RNSS multi-frequency signals in real-time, the proposed SDR A-GNSS receiver utilizes multiple threads implemented on a CPU and multiple NVIDIA CUDA GPGPUs for parallel processing. To evaluate the performance of the proposed SDR A-GNSS receiver, several experiments were performed with field collected data. By the experiments, it was shown that A-GNSS requirements can be satisfied sufficiently utilizing only milliseconds samples. The continuous signal tracking performance was also confirmed with the hundreds of milliseconds data for multi-GNSS/RNSS multi-frequency signals and with the ten-seconds data for multi-GNSS/RNSS single-frequency signals.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1710-1713
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• 2003

We developed the synthetic library automation system. Developed system is comprised of two main units: an auto sorting system of books and a wireless management system. An auto sorting system is composed of a book return machine, a robot system, and an emergency bookshelf. A book return machine is operated by magnetic removal-revival. A wireless management system is development of RFID, or radio frequency identification, and is composed of a RF module and uninhabited return machine and a loss prevention system. The software for the synthetic library automation system is divided into three groups. We realized the developed automation system, and then get the features.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.138-145
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• 2010

In this paper, we report the test results of a small-scale prototype that implements an analogue-beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71~76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Measured performance is very close to the simulated results. An ad-hoc wireless communication system has also been demonstrated. Low BER was measured for an 8PSK data stream at 1.5 Gbps with the receive array beam formed in the direction of arrival of the transmitted signal. To our knowledge this is the first steerable antenna array reported to date in the E-band.

• Journal of Satellite, Information and Communications
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• v.3 no.1
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• pp.1-7
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• 2008

This Paper studied the design and measured results of a flight model for Ku-Band Linearized Channel Amplifier (LCAMP) for communication satellite onboard system. All MMICs, i.e. Variable Gain Amplifier (VGA), Variable Voltage Attenuator (VVA) with analog/digital attenuator, Branch line Hybrid Coupler and Detector for Pre-distorter are fabricated using Thin-Film Hybrid process. The performance of the fabricated module is verified through Radio Frequency circuit simulations and electrical function test in space environment for flight model at 12.25 to 12.75 GHz.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1180-1185
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• 2009

Database is constructed according to the development of information contents technology. But the construction of database using bio-information has not been developed. because it is difficult to collect bio-information. This paper presents how to construct database about sensing temperature and tilt of cow based on bio-information using RF communication. The system consists of 8bit micro-controller, tilt sensor, temperature sensor and RF module.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.8 s.197
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• pp.41-49
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• 2007

In this paper, we proposed a new ultrasonic distance measurement system with high accuracy and long range. To improve accuracy and enlarge range, the time of flight of ultrasonic is calculated by the period detecting method. In the proposed ultrasonic distance measurement system, the ultrasonic transmitter and receiver are separated but synchronized by RF(Radio frequency) module. The experiment has been implemented from short distance 1m to maximum available distance 30m. And the period detecting method is compared with the conventional threshold level method. Experimental results show the accuracy and range of the distance measurement are improved by this period detecting method.