• Journal of Positioning, Navigation, and Timing
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• v.12 no.2
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• pp.177-184
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• 2023

In order to reserve frequency bands for stable operation of the Korean Positioning System (KPS), it must be demonstrated that the impact of interference caused by KPS on other services operating in the same bands is tolerable. The International Telecommunication Union (ITU) provides the radio regulations and a compatibility assessment methodology for the coexistence of different services in limited frequency resources. The purpose of this paper is to investigate the radio regulations regarding the compatibility issues between the KPS and other services sharing the same frequency bands. The results of the investigation show that the RNSS system can be operated in the L5-band under the condition that the Power Flux Density (PFD) and Aggregated Equivalent PFD (AEPFD) thresholds specified in the radio regulations are met. In addition, the ITU recommends that the interference-to-noise ratio (INR) protection criteria be met to prevent degradation of the performance of radar systems operating in the L2/L6-band. In the case of the S-band, coordination of allocations for RDSS space stations with respect to terrestrial services is not required if the PFD does not exceed regulated thresholds regulated by ITU.

• Carbon letters
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• v.13 no.1
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• pp.17-22
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• 2012

Currently, graphene is a topic of very active research in fields from science to potential applications. For various radio-frequency (RF) circuit applications including low-noise amplifiers, the unique ambipolar nature of graphene field-effect transistors can be utilized for high-performance frequency multipliers, mixers and high-speed radiometers. Potential integration of graphene on Silicon substrates with complementary metal-oxide-semiconductor compatibility would also benefit future RF systems. The future success of the RF circuit applications depends on vertical and lateral scaling of graphene metal-oxide-semiconductor field-effect transistors to minimize parasitics and improve gate modulation efficiency in the channel. In this paper, we highlight recent progress in graphene materials, devices, and circuits for RF applications. For passive RF applications, we show its transparent electromagnetic shielding in Ku-band and transparent antenna, where its success depends on quality of materials. We also attempt to discuss future applications and challenges of graphene.

• Journal of Aerospace System Engineering
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• v.1 no.3
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• pp.1-6
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• 2007

The COMS(Communication, Ocean & Meteorological Satellite)is the geostationary satellite which will be performing three main objectives such as meteorological service, ocean monitoring and Ka-band satellite communications. This paper presents the analysis of the electromagnetic radiated compatibility between COMS satellite and the ARIANE 5 launch vehicle. As a conclusion, a good level of confidence can be given at present time to demonstrate the compatibility between the spacecraft and the launcher, and vice versa. No threat has been identified regarding the other units powered during launch mode.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.242-247
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• 2009

In this paper, we investigate interference between short-range radiocommunication devices (SRDs) with frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS) methods when they are in the same frequency bands. In order to analyze interference from unwanted emission of SRD with DSSS to that of FHSS, Monte-Carlo (MC) simulation method is employed and interference probabilities are calculated. We simulate interference scenarios in accordance with several duty cycles and bandwidths. It is also assumed that the propagation model is free space The effect of distance between interfering transmitter and victim receiver is analyzed and bit error rate (BER) is simulated. From the interference analysis results, it is shown that duty cycle affects compatibility more than bandwidth does. Also, we can make sure of the separation distance which satisfies BER criterion when there are only one interfering transmitter and multiple interfering transmitters.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.20-26
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• 2013

We propose PHY Frame Structure for M2M direct communications in licensed frequency band. Especially, the proposed PHY Frame Structure coexists in the same licensed frequency band as currently operating cellular systems. Recently, Machine to Machine (M2M) service markets, including SmartGrid, Mobile Health, and Smart Car, are being rapidly expanded. Supporting M2M services in a specific case can waste Radio Resource in cellular systems. For example, when two M2M terminals communicating to each other are closely located, direct communication is radio resource efficient. In this paper, we set the requirement of maintaining the existing PHY frame structure in cellular systems to meet the backward compatibility. Based on this backward compatibility requirement, PHY frame structure for M2M direct communications is developed while satisfying coexistence with current operating cellular system. The proposed PHY frame structure meets backward compatibility. Accordingly, it is expected that the proposed M2M frame structure is useful for its frequency resource efficiency.

• Journal of electromagnetic engineering and science
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• v.4 no.2
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• pp.51-55
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• 2004

With the progress of the electronics industry and radio communication technology, certain problems, such as electromagnetic interference(EMI), have arisen due to the increased use of electromagnetic(EM) waves. International organizations such as CISPR, FCC, and ANSI have provided the standards for the EM wave environment and for the countermeasure of the electromagnetic compatibility(EMC). EM wave absorbers are used for constructing an anechoic chamber to test and measure EMI and electromagnetic susceptibility(EMS). In this paper, we have designed an one-body EM(electromagnetic) wave ferrite absorber, based on the equivalent material constants method for both normally and obliquely incident waves, whose absorption abilities are superior to that of the conventional ones. The fabricated absorber has a thickness of 27.68 mm and shows an absorption ability over 20 ㏈ in the frequency from 30 MHz to 6 ㎓.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.47-52
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• 2014

Recently, the interest of Wireless Power Transmission(WPT) has been increased for Mobile device application. It is necessary to analyze interference between wireless devices for the efficient use of frequency resource. The Minimum Coupling Loss(MCL) method and the Monte Carlo(MC) method were used for the interference analysis. In this paper, the impact of the 3rd order harmonics of the wireless charger for Cellular Phone on the existing Radio Modem was analyzed. As a result, the separation distance and the allowable number of interferer on the basis of service radius were obtained to protect the Radio Modem from the wireless charger for Cellular Phone.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.418-421
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• 2002

The immunity testing in this study was performed to examine the conducted immunity and radiated immunity in medical instrumentation. Experiments were performed to assess the conducted emission and radiated emission of medical instrumentation such as MRI, ultrasound system, and electro surgical unit etc. The emission testing revolves around conducted emissions (high-frequency currents) on power lines and signal cables. Emission testing also looks at the output of energy through the air (called radiated emissions) and analyzes the strength of those radio-frequency signals generated unintentionally by the electrical medical device that is under test. Finally, this study would provide significant data for furture research or electromagnetic interference and compatibility test in medical instrumentation.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2462-2464
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• 1999

All electric and electronic appliances require their own electromagnetic compatibility. So an industrially advanced nations have made many standards for regulation for their profits thus the researches on the electro-magnetic shielding effect(SE) are being increased. But the SE can not proved its effect by a theory alone because of complex-material problems. This study Present the correlation of the SE and immunity of radiated radio frequency of the electromagnetic field. We have analyzed the theory of shielding effect to the shield texture. It has been proved that experimental results showed this effects have intensive relations to the electromagnetic field immunity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2019-2022
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• 2016

In the presence of an electrically conducting medical lead, radio frequency (RF) coils in magnetic resonance imaging (MRI) systems may concentrate the RF energy and cause tissue heating near the lead. A novel design for a medical lead to reduce this heating by introducing pins in the lead is presented. Peak 10 g specific absorption rate (SAR) in heart tissue, an indicator of heating, was calculated and compared for both conventional (Medtronic) lead design and our proposed design. Remcom XFdtd software was used to calculate the peak SAR distribution in a realistic model of the human body. The model contained a medical lead that was exposed to RF magnetic fields at 64 MHz (1.5 T), 128 MHz (3 T) and 300 MHz (7 T) using a model of an MR birdcage body coil. The proposed design of adding pins to the medical lead can significantly reduce the heating from different MRI systems.