• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.94-101
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• 2009

This paper presents scalable modeling of spiral inductors for RFIC design based on $0.13{\mu}m$ RF CMOS process. For scalable modeling, several inductor patterns are designed and fabricated with variations of width, number of turns and inner radius. Feeding structures are optimized for accurate de-embedding of pad effects. After measuring the S parameters of the fabricated patterns, double-$\pi$ equivalent circuit parameters are extracted for each device and their geometrical dependences are modeled as scalable functions. The inductor library provides two types of models including standard and symmetric inductors. Standard and symmetric inductors have the range of $0.12{\sim}10.7nH$ and $0.08{\sim}13.6nH$ respectively. The models are valid up to 30GHz or self-resonance frequency. Through this research, a scalable inductor library with an error rate below 10% is developed for $0.13{\mu}m$ RF CMOS process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.121-124
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• 2008

In this paper, we will design a 800MHz broadband antenna after a problem of the narrow bandwidth is improved. This multiple band antenna unifies the CDMA(Code Division Multiple Access), GSM(Global System for Mobile telecommunication) and TRS(Trunked Radio System) band in the UHF bandwidth, and then it is possible at the shore base station or repeater as the commercial use. It used the duplex resonance effect It had the L-shaped feeding structure which adds the V-slot. And it improved profit using stack structure. It was measured that the frequency bandwidth of the designed antenna which is planed $792{\sim}1040MHz$ with 248MHz(33%). And the antenna gain is 9.4dBi, 3dB beam width $60^{\circ}$ in radiation pattern.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.328-334
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• 2012

This paper proposes a design technique of wide-band antenna for handy phone with 700 MHz LTE(Long Term Evolution) low frequency bandwidth. The proposed antenna based on the PIFA(Planar Inverted-F type Antenna) structure was designed and considered. In order to realize the wide bandwidth, a round structure which is able to control the electric path length of current and a branch line element which can be obtain the dual resonance characteristics were introduced in this design. As a result, It was realized about 95 MHz bandwidth in spite of very small space of $30{\times}34mm$ used for FR-4 substrate with relative permitivity of 4.4 at 700 MHz band. Measurement results of return loss, bandwidth and gain radiation pattern were agreed well with their calculation results.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.1
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• pp.11-17
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• 2007

Effects of combustion chamber design on combustion stability characteristics of a full-scale gas generator were studied experimentally. Thirty seven double-swirl injectors with recess number of 1.5 were distributed in the injector head, which significantly influences combustion performance. The characteristics of combustion stability were inspected by the parametric variations such as changing length and diameter of the combustion chamber and installing a turbulence ring. The experimental result shows that as the effective length of the combustion chamber decreased, an instability frequency took place in a high-frequency region, and the amplitude of the dynamic pressure generally diminished and could be reduced to the unharmful level. However, the dynamic pressure fluctuation in the region of longitudinal resonant frequency could not be suppressed perfectly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1233-1239
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• 2008

In this paper we proposed a novel broadband printed monopole antenna for PCS/IMT-2000/WLAN terminals by widening current flow To compensate narrow bandwidth characteristics which is one of disadvantages of general printed monopole antenna, we add the patch of diamond shape and induce the current in various directions for acquiring broadband characteristics. And frequency characteristics is optimized with Various design parameters. The bandwidth of the realized antenna is $1.66{\sim}3.04\;GHz$(58.72 %) below the return loss of -10 dB which contain the required band-width of PCS/IMT-2000/WLAN band.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.144-151
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• 2015

The present study proposes a method for modeling a SONAR transducer with dual resonance. The Butterworth van-Dyke (BVD) model, a conventional SONAR transducer modeling method, can model only one resonance point. Hence, to address its disadvantage and to model the dual resonance, a dual resonance BVD model consisting of two serial BVD models is proposed. The two BVD models are connected in a series, and each simulate resonance at low frequency and high frequency, which allows the modeling of two resonance points. Eight elements compose the equivalent circuit by connecting the BVD models in a series, which is twice as great as that of the existing BVD model. The element value of the dual resonance BVD model is extracted by using the particle swarm optimization method. Analysis was also performed to identify the effects of changes in the value of elements that compose the equivalent circuit on the impedance characteristics of the equivalent circuit through simulation in which element values varied.

• Composites Research
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• v.26 no.5
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• pp.279-288
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• 2013

In this paper, the delamination and deformed FSS caused by residual stresses in the Loop type FSS embedded composites and the transmission characteristic changes due to deformation of FSS by residual stresses were studied. FSS may have different electromagnetic characteristics depending on the type of element, design variables, and array. Therefore, design variables of square loop FSS embedded composites structures were determined to obtain the transmission characteristic for X-band (8~12 GHz). Then the design variables of other types of loops (triangular loop and circular loop) were determined based on the dimensions of square loop. Thereafter, the residual stresses and transmission characteristics of FSS embedded composite structures with various single and double loop FSS's, and stacking sequence of composite laminates were compared.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.967-973
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• 2009

In this paper, X-band satellite communication oscillator of double phase locked is implemented by constructing a couple of phased-locked loop, and then we have analyzed the phase noise of designed PLL-DRO. The designed phase-locked oscillator is consist of series feedback DRO, frequency divider, phase detector, loop filter and programmable PLL-IC. By dividing oscillation frequency of 12.6 GHz into two frequencies, it exhibits output power of 15.32 dBm at 6.3 GHz. Phase noises of implemented oscillator are -81 dBc/Hz@100Hz, -100.86 dBc/Hz@1 kHz, -111.12 dBc/Hz@10 kHz, -116 dBc/Hz@100 kHz and -140.49 dBc/Hz@1 MHz respectively. These indicate excellent stable operation of oscillator and very good phase noise characteristics.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.211-214
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• 2007

In this paper, we have designed microstrip antenna if 800[MHz] band It will be able to integrate TRS(Trunked Radio System), GSM(Global System for Mobile telecommunication) band including the CDMA(Code Division Multiple Access) band we designed repeater and a base station antenna which is possible at the ship and marine of safety. It is improves a narrow bandwidth problem of microstrip antenna. It had U-shaped feeding structure at a rectangular patch And ground or feeding structure used between dielectric constant(${\varepsilon}_T$ = 2.1), patch or feeding structure used between dielectric constant(${\varepsilon}_T$ =1). So it used a duplex resonance effect Designed frequency bandwith(V5WR 2:1) if the antenna showed good characteristic of $780[MHz]{\sim}1.83[GHz]$ to 2.61[GHz]. Also the E-plan and H-plan all profit 9.4[dBi] above, the 3[dB] beam width showed the characteristic over the E-plan and H-plan $60^{\circ}$ to be improved.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.31-37
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• 2002

전자파 잔향실(Reverberating Shielded Enclosure)의 개념은 전자파 차폐실(Shielded Enclosure)에서 얻어진 측정결과를 개선하기 위하여 1968년도에 제안되었다. 이후 Reverberating 또는 Mode-Stirred Chamber는 EM Immunity 측정뿐만 아니라 EMI측정에서도 많이 적용되어 왔지만, 국제 표준 방식으로 적용되어 오지 못하다가 최근 EMI 복사 전력 측정 및 EM Immunity 측정시설로 유용하게 사용될 수 있다는 점이 부각되어 국제 표준 방식으로 적용하자는 분위기가 무르익어 이에 대한 활발한 논의가 계속되어 오고 있다. 이러한 전자파 잔향실을 이용하여 EMI 및 EMS 시험을 실시할 수 있는 방법을 규격화시키자는 제안이 '96년 프랑스 Mandelieu 국제 전자파 장해 특별위원회(CISPR:International Special Committee on Radio Interference)회의에서 검토된 후 '97년 일본 Yokosuka CISPR 회의에서 정식의제로 채택되었다. 이 안건에 대하여 대부분의 국가들이 제안 취지에 찬성하여 NWIP(New Work Item Proposal) 문서가 각국에서 회람되었다. 초기 전자파 잔향실은 전자파 장해 및 복사 내성 측정을 위한 대용시험 시설로서 1968년 미국 Mendes에 의해 전자파 차폐실 구조에 Stirrer를 이용하여 필드의 균일도를 확보할 수 있다는 전자파 잔향실 개념이 처음으로 제안되었다. 이후 이 분야의 연구는 미국 표준 기술 연구소(NIST: National Institute of Standard and Technology)등에서 연구가 활발히 진행되고 있으며, 국제 표준화 기구인 CISPR에서 전자파 장해 및 내성 시험을 위한 대용시험 시설로서 활용하기 위하여 규격 작업이 진행중에 있다. 또한 최근 전자파 장해 방지를 위한 규제 주파수가 1∼18㎓ 까지 확장됨에 따라 이 주파수 대역에서 시험장으로 활용할 수 있는 전자파 잔향실이 새롭게 부각되고 있다. 전자파 잔향실은 기본적으로 공진 모드를 활용하기 때문에 일정한 크기의 잔향실 내부에서 전자파 균일성을 확보할 수 있는 모드 수에 의해 하한 주파수가 결정되며 충분한 모드 분포상태에서 Stirrer를 사용하여 필드 경계를 이동시킴으로서 확률적으로 균일한 필드분포를 확보하게 된다. 주파수가 증가함에 따라 모드수는 증가하기 때문에 하한 주파수 이상의 대역에 대한 시험시설로 활용할 수 있으며, 특히 ㎓ 대역에서 사용하기에 적합한 대용시험시설이라고 볼 수 있다.