• Journal of the Microelectronics and Packaging Society
• /
• v.6 no.3
• /
• pp.1-7
• /
• 1999

A single RF transceiver evaluation board have been developed for the purpose of application to the 900MHz band transceiver contained RF-IC chip And environment test was evaluated. The RF-IC chipset includes LNA(Low Noise Amplifier), down-conversion mixer, AGC(Automatic Gain Controller), switched capacitor filter and down sampling mixer. The RF evaluation board for the testing of chipset contained various external matching circuits, filters such as RF/IF SAW(Surface Acoustic Wave) filter and duplexer and power supply circuits. With the range of 2.7~3.3V the operated chip revealed moderate power consumption of 42mA. The chip was well operated at the receiving frequency of 925~960MHz. Measurement result is similar to general RF receiving specification of the 900MHz digital mobile phone.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.86-86
• /
• 2011

RF magnetron sputtering을 이용하여 RF파워 변화에 따라 GZO 박막을 제작하였다. 박막제작은 유리기판 위에 하였고, 전기적, 광학적 특성을 조사하였다. 박막의 증착시 초기 압력은 $2.0{\times}10^{-6}Torr$, 증착온도는 상온으로 고정하여 증착하였으며, 기판은 Corning 1737 유리 기판을 사용하였다. RF 파워 공정변수는 20W, 50W, 80W, 110W로 변화를 시켰다. 유리기판에 증착된 모든 GZO박막은 200 nm의 두께로 증착되었으며 모든 GZO 박막에서 85% 이상의 투과율을 나타내었다. RF파워가 낮을수록 투과율을 증가하였으며, 광학적 밴드갭 또한 증가하였다. 공정별로 제작된 모든 GZO박막에서 (002)면의 배향성이 관찰되었고, RF파워가 낮을수록 박막의 결정성은 향상되었다. Hall 측정 결과 RF파워가 20W일 때 전기비저항 $1.85{\times}10^{-3}{\Omega}cm$, 전하의 농도 $3.794{\times}10^{20}cm^{-3}$, 이동도 $8.89cm^2V^{-1}s^{-1}$로 전극으로서의 특성을 나타내었다. GZO 박막의 경우 RF 파워가 낮을수록 결정성이 높아지고, 전극의 특성을 갖는 것을 확인할 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.11
• /
• pp.62-69
• /
• 1998

The general degradation model has been applied to analyze the hot carrier induced degradation of the DC and RF characteristics of RF-nMOSFET. The degradation of cut-off frequency has been severer than the degradation of bulk MOSFET drain current. The value of the degradation rate n and the degradation parameter m for RF-nMOSFET has been equal to those for bulk MOSFET. The decrease of device degradation with the increase of fingers could be explained by the large source/drain parasitic resistance and drain saturation voltage. It has been also found that the RF performance degradation could be explained by the decrease of $g_{m}$ and $C_{gd}$ and the increase of $g_{ds}$ after stress. The degradation of the DC and RF characteristics of RF-nMOSFET could be predicted by the measurement of the substrate current.t.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.9
• /
• pp.1-5
• /
• 2011

In this paper, we investigated the characteristics of AlGaN/GaN HEMTs to optimize their DC and RF characteristics by using a two-dimensional device simulator. First, we analyzed the variation of the DC characteristics with respect to the variation of 2DEG concentrations when varying the Al mole fraction and the thickness of the AlGaN layer. Then, we examined the variation of the RF characteristics by varying the size and the location of the gate, source and drain electrodes. When the Al mole fraction increased from 0.2 to 0.45, both the transconductance and I-V characteristics increased. On the other hand, the I-V characteristics were improved but transconductance was decreased as the thickness of the AlGaN layer increased from 10nm to 50nm. In the RF characteristics, the gate length was found to be the most influential parameter, and the RF characteristics were improved when the gate length was shorten.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.1
• /
• pp.13-22
• /
• 2001

This paper presents three dimensional structure of RF packages and the improvement effect of its electrical characteristics when implementing RF transceivers. We divided RF modules into several subunits following each subunit function based on the partitioning algorithm which suggests a method of three dimension stacking interconnection, PAA(pad area array) interconnection and stacking of three dimensional RF package structures. 224MHz ITS(Intelligent Transportation System) RF module subdivided into subunits of functional blocks of a receiver(RX), a transmitter(TX), a phase locked loop(PLL) and power(PWR) unit, simultaneously meeting the requirements of impedance characteristic and system stability. Each sub­functional unit has its own frequency region of 224MHz, 21.4MHz, and 450KHz~DC. The signal gain of receiver and transmitter unit showed 18.9㏈, 23.9㏈. PLL and PWR modules also provided stable phase locking, constant voltages which agree with design specifications and maximize their characteristics. The RF module of three dimension stacking structure showed $48cm^3$, 76.9％ reduction in volume and 4.8cm, 28.4％ in net length, 41.8$^{\circ}C$, 37% in maximum operating temperature, respectively. We have found that three dimensional PAA package structure is able to produce high speed, high density, low power characteristics and to improve its functional characteristics by subdividing RF modules according to the subunit function and the operating frequency, and the features of physical volume, electrical characteristics, and thermal conditions compared to two dimensional RF circuit modules.

• Journal of the Korean Vacuum Society
• /
• v.20 no.5
• /
• pp.345-355
• /
• 2011

GaAs-based metamorphic high electron mobility transistors (MHEMTs) and InP-based high electron mobility transistors (HEMTs) have good microwave and millimeter-wave frequency performance with lower minimum noise figure. MHEMTs have some advantages, especially for cost, compared with InP-based ones. In this paper, InAlAs/InxGa1-xAs/GaAs MHEMTs are simulated for DC/RF small-signal analysis. The hydrodynamic simulation parameters are calibrated to a fabricated 0.1-${\mu}m$ ${\Gamma}$-gate MHEMT device having the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ heterostructure on the GaAs substrate, and the simulations for RF small-signal characteristics are performed, compared with the measured data, and analyzed for the devices. In addition, the simulations for the DC/RF characteristics of the MHEMTs with different gate-recess structures are performed, compared and analyzed.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.10
• /
• pp.60-66
• /
• 1998

The hot carrier induced performance degradation of 0.8${\mu}{\textrm}{m}$ RF NMOSFET has been investigated within the general framework of the degradation mechanism. The device degradation model of an unit finger gate MOSFET could be applied for the device degradation of the multi finger gate RF NMOSFET. The reduction of cut-off frequency and maximum frequency can be explained by the transconductance reduction and the drain output conductance increase, which are due to the interface state generation after the hot carrier stressing. From the correlation between hot carrier induced DC and RF performance degradation, we can predict the RF performance degradation just by the DC performance degradation measurement.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.4
• /
• pp.299-305
• /
• 2010

Purposes: The purposes of this study were to investigate the optical, structural and electrical properties of the antimony doped tin oxide(ATO) thin films according to certain variable deposition conditions, such as RF input power and T-S (target-substrate) distance change, using transparent conducting oxide (TCO). Methods: ATO thin films of Sb concentration ratio with $SnO_2:Sb_2O_5$ = 95:5 wt% were deposited at room temperature by RF magnetron sputtering method. Results: ATO thin films were most sensitive to the RF input power: light transmittance was 78% at RF input power of 30W, and 0.56 nm for the surface roughness and 1007 $\Omega{\cdot}cm^{-2}$ for the sheet resistance as well. Conclusions: It was found that ATO thin films were showed the large change in its characteristics of structural, optical and electrical properties which were affected by T-S distance and RF input power.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.13 no.2
• /
• pp.60-70
• /
• 2002

최근 고성능/고집적 RF 소자 및 시스템들의 경박 단소화 추세에 따라 RF 무선 통신 분야에도 초소형미세 가공 기술인 MEMS 기술이 크게 주목받고 있다. 이에 본 고에서는 RF 부품 및 시스템을 MEMS 기술로서 실장하는 RF MEMS 패키지 기술에 대하여 간단히 살펴보았다. 우선, 실리콘 기반의 MEMS 패키지가 우수한 열 전달 특성과 저 손실의 고주파특성으로 인해 RF 시스템의 실장에 매우 적합함을 확인하였다. 또한, MEMS 기술을 이용함으로써 RF회로와 패키지 제작 공정이 동시에 이루어질 수 있도록 하는 일괄터리공정에 대하여 소개하였다.

• Journal of the Institute of Convergence Signal Processing
• /
• v.12 no.3
• /
• pp.217-221
• /
• 2011

GaAs-based and InP-based HEMTs(High Electron Mobility Transistors) have good microwave and millimeter-wave frequency performance with lower minimum noise figure. GaAs-based MHEMTs(Metamorphic HEMTs) have some advantages, especially for cost, compared with InP-based ones. In this paper, the RF small-signal circuits of MHEMTs are simulated and analyzed for the design of millimeter-wave application systems. The simulation analysis for RF small-signal frequency can help and give some insights about the MHEMTs for the design of millimeter-wave application and communication systems.