• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.3 s.106
• /
• pp.307-316
• /
• 2006

In this paper the analytical method, namely advanced minimum coupling loss(A-MCL), was proposed in order to analyze the coexistence of OFDM-based systems beyond 3G(B3G) with point-to point(PP) fixed service(FS) microwave systems. Our proposed method is based on a power spectral density(PSD) analysis. So it can be easily applicable to analyze the coexistence of OFDM-based systems B3G using flexible spectrum usage(FSU) with other systems, where the conventional MCL method cannot allocate transmit power partially to some subcarriers which overlap the band of a victim system. By applying the conventional MCL method and the A-MCL method, interfering power levels at the receiver of a interfered system are respectively calculated. A-MCL can calculate interference power more accurately than MCL by the maximum value of 4.5 dB. Therefore it can be concluded that our prosed method, namely A-MCL, is applicable to a sharing analysis of OFDM-based systems B3G.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.2 no.4
• /
• pp.295-301
• /
• 2002

In this paper, solenoid-type 3-D passives (inductors and transformers) have been designed, fabricated, and characterized by using electroplating techniques, wire bonding techniques, multi-layer thick photoresist, and low temperature processes which are compatible with semiconductor circuitry fabrication. Two different fabrication approaches are performed to develop the solenoid-type 3-D passives and relationship of performance characteristics and geometry is also deeply investigated such as windings, cross-sectional area of core, spacing between windings, and turn ratio. Fully integrated inductor has a quality factor of 31 at 6 GHz, an inductance of 2.7 nH, and a self resonant frequency of 15.8 GHz. Bonded wire inductor has a quality factor of 120, an inductance of 20 nH, and a self resonant frequency of 8 GHz. Integrated transformers with turn ratios of 1:1 and n:l have the minimum insertion loss of about 0.6 dB and the wide bandwidth of a few GHz.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.49-52
• /
• 2001

본 논문에서는 몬테카를로 기법 및 최소결합손실(MCL : Minimum Coupling Loss)기법을 기반으로 하여 무선통신 서비스간 보호비를 만족시키도록 최적의 보호대역을 자동으로 설정할 수 있는 알고리즘을 개발하고 그 견과를 기술하였다. 여기서 개발된 보호대역 자동 설정 알고리즘은 통계적인 몬테카를로 기법 및 간섭원과 대상 수신기 사이에 간섭이 존재하지 않도록 요구되는 이격도 계산을 위한 최소결합손실기법을 적용하여, 주어진 간섭보호비를 만족할 수 있는 최악의 상황에 대한 보호대역을 먼저 설정한 후 보호대역값을 변화시키면서 희망 수신기에서의 간섭확률을 계산을 통해 최적의 보호대역을 설정할 수 있다. 이 기법은 어떠한 형태의 무선통신 서비스에 대해서도 동시에 두가지의 간섭원이 영향이 미칠 경우에도 적용할 수 있도록 설계되었다. 또한 본 연구에서는 TDD시스템간의 간섭 시나리오를 설정하고, 개발된 보호대역 자동 선정 알고리즘을 사용한 시뮬레이터와 ITU-R에서 개발된 SEAMCAT에 의해 얻어진 보호대역 도출 결과를 비교, 분석함으로써 개발된 알고리즘의 신뢰성을 검증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.3
• /
• pp.906-918
• /
• 2012

Wireless Fidelity (WiFi) and Wireless microphone are assumed to operate on adjacent channels in TV White Spaces(TVWS). The Scenario of WiFi potentially interfering with Wireless microphone is analyzed through Minimum Coupling Loss (MCL) and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) based on the Monte-Carlo simulation method. In the case of single WiFi interfering with Wireless microphone, the protection distance between WiFi and the Wireless microphone should be at least 25.12 m to avoid WiFi impact on Wireless microphone. When the active number of WiFi is 12, the guard band between WiFi and Wireless microphone should not be less than 4.97 MHz to guarantee that WiFi does not interfere with the Wireless microphone.

• ETRI Journal
• /
• v.33 no.5
• /
• pp.802-805
• /
• 2011

This letter presents a K-band polarization reconfigurable antenna integrated with a silicon radio frequency MEMS switch into the form of a compact package. The proposed antenna can change its state from linear polarization (LP) to circular polarization (CP) by actuating the MEMS switch, which controls the configuration of the coupling ring slot. Low-loss quartz is used for a radiating patch substrate and at the same time for a packaging lid by stacking it onto the MEMS substrate, which can increase the system integrity. The fabricated antenna shows broadband impedance matching and exhibits high axial ratios better than 15 dB in the LP and small axial ratios in the CP, with a minimum value of 0.002 dB at 20.8 GHz in the K-band.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.2
• /
• pp.73-78
• /
• 2004

AIN thin film has been deposited on the $AI_2$$O_3$substrate with reactive radio frequency( RF) magnetron sputtering method. In this work, elelctromechanical coupling coefficient of AIN thin film was increased with an increase of AIN thin film thickness, and the maximum value was 0.11%. Insertion loss of SAW device was decreased with an increase of AIN thin film thickness and the minimum value was 33［㏈］. SAW velocity of IDTs/AIN/$AI_2$$O_3$structure and IDTs/AIN/$AI_2$$O_3$/Si structure were about 5480［㎧］and 5040［㎧］respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1997.11a
• /
• pp.149-152
• /
• 1997

High-power piezoelectric materials are being developed for applications such as actuators and ultrasonic motors. In this paper, ferroelectric property of iron-doped 0.57 (Sc$_{1}$2//Nb$_{1}$2/)O$_3$-0.43 PbTiO$_3$. which is the morphotropic phase boundary composition for the PSN-PT system, was investigated. The maximum dielectric constant ( $\varepsilon$$_{33}$/$\varepsilon$$_{0}$ = 2551) and the minimum dielectric loss(tan $\delta$ = 0.51 %) at room temperature were obtained at 01. wt% and 0.3 wt% of iron additions. With additions of the Fe$_2$O$_3$ the electromechanical coupling factor of radial mode k$_{p}$ and the piezoelectric coefficient d$_{33}$ were slightly decreased, on the other hand the mechanical quality factor was increased significantly. The highest mechanical quality factor (Qm= 297) was obtained at 0.3 wt% Fe$_2$O$_3$, which is 4.4 times larger than that of pure 0.57 PSN-0.43PT ceramics. The temperature dependence of the dielectric constant and dielectic loss was observed between 2$0^{\circ}C$ and 35$0^{\circ}C$ .X> .X> .

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.2
• /
• pp.124-129
• /
• 2007

Dielectric and piezoelectric properties of $0.57Pb(Sc_{1/2}Nb_{1/2})O_{3}-0.43PbTiO_{3}$, which is the morphotropic phase boundary composition for the PSN-PT system, were investigated as a function of $Fe_{2}O_{3},\;Nb_{2}O_{5}\;and\;MnO_{2}$ addition 0 wt% to 0.9 wt%. The maximum dielectric constant of ${\varepsilon}_{33}/{\varepsilon}_{o}=2054$ and the minimum dielectric loss of $tan{\delta}=0.37\;%$ at room temperature were obtained at 0.1 wt% of $Fe_{2}O_{3}$ and 0.5 wt% of $MnO_{2}$ addition, respectively. With addition of 0.5 wt% $Nb_{2}O_{5}$ and $0.5\;wt%\;MnO_{2}$, the electromechanical coupling factor $k_{p}$ and mecanical quality factor $Q_{m}$ were significantly increased, respectively. The maximum electromechanical coupling factor $k_{p}=61.5\;%$ was obtained by addition of $Nb_{2}O_{5}$ and high mechanical quality factor $Q_{m}=919$ was obtained by addition of $MnO_{2}$. The $Q_{m}(=919)$ value is 3.3 times larger than that of non-doped 0.57PSN-0.43PT ceramics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.5 s.108
• /
• pp.440-450
• /
• 2006

In this paper, the frequency sharing issue between time division duplex-orthogonal frequency division multiplexing/orthogonal frequency division multiple access(TDD-OFDM/OFDMA) based systems beyond third generation(B3G) and fixed Satellite Service(FSS) earth station has been studied. The conventional advanced minimum coupling loss(A-MCL) is adopted to assess the interference from a single base station(BS) of B3G systems. The aggregated interferences from base stations and mobile stations(MS) are evaluated by applying the extended A-MCL and analysed with a cumulative density function(CDF). The minimum distances that enable a single FSS earth station to sharing the frequency with a single BS are between 4 and 53.3 km. In the case of 20 MS per sector, the BS-to-BS distance and the minimum distance between a ES and BS are 6.5 and 2.8 km, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.1A
• /
• pp.125-133
• /
• 2007

In this paper, the frequency sharing issue between cellular time division duplex-orthogonal frequency division multiple access (TDD-OFDMA) Systems and terrestrial Fixed Systems has been studied. The conventional advanced minimum coupling loss (A-MCL) includes only the formulation to calculate the interference from one interfering system. Therefore, A-MCL must be modified to assess the aggregated interference from base stations(BS) and mobile stations(MS). By applying the modified model, the coexistence analysis are done according to the average number of MS per sector, BS-to-BS distance, and the main beam direction of the terrestrial fixed system. In the case of 20 MS per sector, the BS-to-BS distance and the minimum distance between a terrestrial fixed system and BS are 5.8 km and 2.5 km, respectively. It is about 25dB that the difference between maximum and minimum interference signal power which varies with the main beam direction of the terrestrial fixed system. Moreover, for 40% of the main beam direction of the terrestrial fixed system, interference signal power is less than the maximum permissible interference.