• Title, Summary, Keyword: Microwave properly

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A CMOS Compatible Micromachined Microwave Power Sensor (CMOS 공정과 호환되는 마이크로머시닝 기술을 이용한 마이크로파 전력센서)

  • 이대성;이경일;황학인;이원호;전형우;김왕섭
    • Proceedings of the IEEK Conference
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    • pp.439-442
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    • 2002
  • We present in this Paper a microwave Power sensor fabricated by a standard CMOS process and a bulk micromachining process. The sensor consists of a CPW transmission line, a resistor as a healer, and thermocouple arrays. An input microwave heater, the resistor so that the temperature rises proportionally to the microwave power and tile thermocouple arrays convert it to an electrical signal. The sensor uses air bridged 8round of CPW realized by wire bonding to reduce tile device size and cost and to improve the thermal impedance. Al/poly-Si junctions are used for the thermocouples. Poly-Si is used for tile resister and Aluminium is for transmission line. The resistor and hot junctions of the thermocouples are placed on a low stress silicon nitride diaphragm to minimize a thermal loss. The fabricated device operates properly from 1㎼ to 100㎽\ulcorner of input power. The sensitivity was measured to be ,3.2~4.7 V/W.

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Microwave Properties of Ag Conducting Paste with Various Preparation Conditions (Ag가 함유된 전도성 도료의 제조 조건에 따른 고주파 특성)

  • Park, Sang-Hoon;Kim, Jeong-Pyo;Seong, Won-Mo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.9
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    • pp.827-832
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    • 2005
  • Dual band internal antennas were fabricated with Ag conducting paste of various preparation conditions and different print thickness by silk screen print. We have investigated microwave properties were compared Ag conducting paste antenna with copperplate antenna at 800 MHz and 1,800 MHz. Gain of Ag conducting paste antenna was improved when preparation conditions were the single size Ag particle, using dry type resin and high Ag containing percent. However, it was lower than that of copperplate antenna within $0.1\~2.0dBi$ at 800MHz. In addition, it was improved at 800MHz when thickness of Ag conducting paste was printed more than skin depth but it was held after critical print thickness. On the other hand, it was reached level of copperplate antenna at 1,800MHz.

Analytic Model of Spin-Torque Oscillators (STO) for Circuit-Level Simulation

  • Ahn, Sora;Lim, Hyein;Shin, Hyungsoon;Lee, Seungjun
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.13 no.1
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    • pp.28-33
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    • 2013
  • Spin-torque oscillators (STO) is a new device that can be used as a tunable microwave source in various wireless devices. Spin-transfer torque effect in magnetic multilayered nanostructure can induce precession of magnetization when bias current and external magnetic field are properly applied, and a microwave signal is generated from that precession. We proposed a semi-empirical circuit-level model of an STO in previous work. In this paper, we present a refined STO model which gives more accuracy by considering physical phenomena in the calculation of effective field. Characteristics of the STO are expressed as functions of external magnetic field and bias current in Verilog-A HDL such that they can be simulated with circuit-level simulators such as Hspice. The simulation results are in good agreement with the experimental data.

Evaluations of Radar Absorbing Coating materials in the Microwave Frequencies (마이크로 주파수에서 전파 흡수성 코팅재료의 특성 평가)

  • 임종인;김찬욱;오택수
    • Journal of the Korean Ceramic Society
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    • v.36 no.6
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    • pp.571-576
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    • 1999
  • This paper describes both electromagnetic properties and electromagnetic-wave absorbind (EMA) characteristics of the radar absorbing coating materials in the microwave frequencies. The coating materials are prepared by mixing ferrite powder with epoxy resin polymers. The electromagnetic property and the EMA characteristics of the coating materials are measured in the frequency ranges between 0.2 GHz and 15GHz using the S-parameter method. The results show that the typical coating material has ({{{{ {μ }`_{r } ^{' } }} of about 2 and ({{{{ { ε}`_{r } ^{' } }} of about 4. And the coating materials have a little EMA characteristics in the frequency from 4 to 6 GHz and more improved EMA characteristics around 12 GHz And it is desirable for improvement of the EMA characteristics of the coating materials to properly select electromagnetic properties of constitutional materials inthe interesting frequency ranges.

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Effect of Pb based flux on the Microwave Dielectric Properties of PCFN-PZW System (PCFN-PZW계의 마이크로파 유전 특성에 미치는 Pb계 Flux의 영향)

  • 강동헌;설충의;차훈주;김영호;길상근;조봉희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.12
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    • pp.1027-1032
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    • 2002
  • (Pb$\_$0.4/Ca$\_$0.6/)(Fe$\_$1/2/Nb$\_$1/2/)O$_3$ system was modified by 10 mol% Pb(Zn$\_$1/2/W$\_$1/2/)O$_3$ addition and their sinterability and microwave properties were investigated as a function of the amount of flux (0.975PbO-0.025SnO$_2$). With increasing flux content, single perovskite phase was maintained up to 3 wt% flux addition and further addition led to the presence of Pb-rich second phase which was confirmed by EDS analysis. The apparent densities of PCFN-PZW specimen increased and showed maximum values at 2.5 wt% flux addition for the Ts=1000$^{\circ}C$ and 2.0wt% flux addition for the Ts=1050$^{\circ}C$, respectively. The dielectric constant and Q$.$f values strongly depended on the variation of density and microstructure, where the optimum values of $\varepsilon$$\_$r/ = 91.95, Q$.$f = 5938GHz, TCF = +8.15ppm/$^{\circ}C$ were obtained for the 2.5wt% flux added PCFN-PZW specimen sintered at 1000$^{\circ}C$ for 4h.

A Study on Surface Acoustic-Wave Amplfication in Piezo-electric Crystals (Piezo 압전 결정체에서의 표면탄성파 증폭에 관한 연구)

  • 이윤현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.6 no.1
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    • pp.51-57
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    • 1981
  • Carriers moving in a semiconductor can impart gain or loss to an acousic wave traveling through Piezo-electric materials. In this paper, surface a coustic wave amplifiers, which employ the interaction between carriers drifting in a semiconduct or film and electic fields accompanying a Rayleigh wave propagating on a Piezoelectric substrate, are described. The effect of various electromagnetic boundary condition on th propagation of surface waves in Piezoelectrics is considered. An expression for the dependence of surface wave velocity on electic boundary conditions is derived. Calculations show that, for properly prepared material, significant amplification is expected up to the microwave frequencies. At high frequencies, gain is reduced because electro diffusion smooths out the electron bucning necessary for amplification.

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A Highly Integrated HBT Downconverter MMIC for Application to One-chip RF tranceiver solution (One-chip 고주파 단말기에의 응용을 위한 고집적 HBT 다운컨버터 MMIC)

  • Yun, Young
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.6
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    • pp.777-783
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    • 2007
  • In this work, a highly integrated downconverter MMIC employing HBT(heterojunction bipolar transistor) was developed for application to one chip tranceiver solution of Ku-band commercial wireless communication system. The downconverter MMIC (monolithic microwave integrated circuit) includes mixer filter. amplifier and input/output matching circuit. Especially, spiral inductor structures employing SiN film were used for a suppression of LO and its second harmonic leakage signals. Concretely, they were properly designed so that the self-resonance frequency was accurately tuned to LO and its second harmonic frequency, and they were integrated on the downconverter MMIC.

Design of 60 ㎓ Millimeter-Wave Frequency Doubler using Distributed Structure

  • Park, Won;Lee, Kang-Ho;Kim, Sam-Dong;Park, Hyung-Moo;Rhee, Jin-Koo;Koo, Kyung-Heon
    • Journal of electromagnetic engineering and science
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    • v.4 no.2
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    • pp.87-92
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    • 2004
  • A millimeter-wave distributed frequency doubler has been designed with distributed block and frequency tunable output reflectors. The simulated conversion loss of 9.5 ㏈ to 7.7 ㏈ from 54.6 ㎓ to 62.4 ㎓ output frequencies is achieved with fundamental and third harmonic signal rejections of more than 10 ㏈c. The fabricated chip has the size of 1.2 mm${\times}$1.0 mm. Some measured results of frequency and bias dependent characteristics are presented for the fabricated PHEMT MMIC frequency doubler. The designed doubler has two transistors, and if one of the transistors fails the doubler unit still operates with reduced gain. The failure effect of the PHEMT has been simulated, and compared to the measured data of which one PHEMT is not operating properly.

Biological Damage and Risk Assessment of The Wood Cultural Properties in Fire Prevention Area (화재방제구역에 따른 목조문화재 생물손상 및 생물위험도 평가)

  • Kim, Dae Woon;Chung, Yong Jae
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.1
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    • pp.104-111
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    • 2015
  • The three-year inspection of 20 tree stumps in the fire prevention area around the wooden building confirmed that termite colonies had been rapidly spread. In particular, four buildings among thirty one wooden buildings of Songgwang-sa temple were infected by the termite, indicating that the habitate of termite has been spread across the fire prevention area over the temple area. However, a non-destructive microwave diagnosis showed that internal damages have been progressed until now, suggesting a high risk to the building. These results suggest that the fire prevention area should be properly maintained to have harmful element controlled. Therefore, effective methods are required to eliminate tree stumps or wood materials used to establish fire prevention area near wooden buildings.

Low-temperature Sintering and Microwave Dielectric Properties of the B2O3 and CuO-added Ba(Mg1/3Nb2/3)O3 Ceramics (B2O3와 CuO가 첨가된 Ba(Mg1/3Nb2/3)O3 세라믹스의 저온소결과 마이크로파 유전특성 연구)

  • Lim, Jong-Bong;Son, Jin-Ok;Nahm, Sahn;Yoo, Myong-Jea;Lee, Woo-Sung;Kang, Nam-Kee;Lee, Hwack-Joo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.1
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    • pp.38-42
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    • 2005
  • B$_2$O$_3$ added Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (BBMN) ceramics were not sintered below 900 $^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at 850 $^{\circ}C$. The amount of the $Ba_2$B$_2$O$_{5}$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the B$_2$O$_3$ inhibiting the reaction between B$_2$O$_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and B$_2$O$_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density, the dielectric constant ($\varepsilon$$_{r}$) and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf = 21500 GHz, $\varepsilon$$_{r}$ = 31 and temperature coefficient of resonance frequency($\tau$$_{f}$) = 21.3 ppm/$^{\circ}C$ were obtained for the Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$+2.0 mol%B$_2$O$_3$+10.0 mol%CuO ceramic sintered at 875 $^{\circ}C$ for 2 h.h.2 h.h.