• Journal of the Institute of Electronics and Information Engineers
• /
• v.54 no.6
• /
• pp.25-29
• /
• 2017

This paper presents a hetero-integration of electrostatically actuated RF MEMS Switch and step up DC-DC converter on a redistribution layer using commercial PCB process. RF characteristics of Duroid with $56{\Omega}$ impedance GCPW transmission line and that of FR4 with $59{\Omega}$ impedance CPW transmission line were analyzed. From DC to 6GHz, RF characteristics of Duroid were better than that of FR4, insertion loss was 2.08dB lower, return loss was 3.91dB higher, and isolation was 3.33dB higher.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.757-760
• /
• 1999

Depending upon the existence of the battery, transponder is divided into active and passive transponder. The passive transponder operates without battery and so has no limitation in its operating range and life time. But it needs the RF-DC conversion circuit. In this paper, the analysis and design of the RF-DC conversion circuit in passive transponder operated in high frequency is presented and is confirmed by simulation and experiment.

• Journal of the Korean institute of surface engineering
• /
• v.41 no.5
• /
• pp.214-219
• /
• 2008

Indium tin oxide (ITO) films were deposited on PET substrate by RF superimposed DC magnetron sputtering using ITO (doped with 10 wt% $SnO_2$) target. Substrate temperature was maintained below $750^{\circ}C$ without intentionally substrate heating during the deposition. The discharge voltage of DC power supply was decreased from 280 V to 100 V when superimposed RF power was increased from 0 W to 150 W. The electrical properties of the ITO films were improved with increasing of superimposed RF power. In the result of cyclic bending test, relatively high mechanical property was obtained for the ITO film deposited with RF power of 75 W under DC current of 0.75 A which could be attributed to the decrease of internal stress caused by decrease in both deposition rate and plasma impedance.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.6
• /
• pp.2441-2446
• /
• 2018

This paper presents a radio frequency-to-direct current (RF-to-DC) converter for special RF power harvesting application at 915 MHz. The major featured components of the proposed RF-to-DC converter is the combination of a cross-coupled rectifier and an active diode: first, the cross-coupled rectifier boosts the input voltage to desired level, and an active diode blocks the reverse current, respectively. A prototype was implemented using $0.18{\mu}m$ CMOS technology, and the performance was proven from the fact that the targeted RF harvesting system's full-operation with higher power efficiency; even if the system's input power gets lower (e.g., from nominal 0 to min. -12 dBm), the proposed RF-to-DC converter constantly provides 1.47 V, which is exactly the voltage level to drive follow up system components like DC-to-DC converter and so on. And, maximum power conversion efficiency is 82 % calculated from the 0 dBm input power, 2.3 mA load current.

• Korean Journal of Materials Research
• /
• v.16 no.8
• /
• pp.461-465
• /
• 2006

Chromium (Cr) films were deposited on plain carbon steel sheets by DC and RF magnetron sputtering as well as by electroplating. Effects of DC or RF sputtering power on the deposition rate and properties such as, hardness, surface roughness and corrosion-resistance of the Cr films were investigated. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microcopy (SEM) analyses were performed to investigate the crystal structure, surface roughness, thickness of the Cr films. Salt fog tests were used to evaluate the corrosion resistance of the samples. The deposition rate, hardness, and surface roughness of the Cr film deposited by either DC or RF sputtering increase with the increase of sputtering power but the adhesion strength is nearly independent of the sputtering power. The deposition rate, hardness, and adhesion strength of the Cr film deposited by DC sputtering are higher than those of the Cr film deposited by RF sputtering, but RF sputtering offers smoother surface and higher corrosion-resistance. The sputter-deposited Cr film is harder and has a smoother surface than the electroplated one. The sputter-deposited Cr film also has higher corrosion-resistance than the electroplated one, which may be attributed to the smoother surface of the sputter-deposited film.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.255-258
• /
• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.112-114
• /
• 1998

The passive system requires RF-DC converter. RF-DC converter, which is used in microwave region, is more affected by parasitic elements than used in low frequency region. So it is difficult to make the converter. RF-DC converter usually consists of resonator, shottky diode, capacitor, voltage regulator. In this study, we used the rechargeable battery instead of capacitor. If any passive transponder requires more power than general transponder, battery tech of this components is important to apply for the passive system. In this paper, passive transponder, which requires more power than general passive transponder, is presented and compared to general passive transponder.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.202-202
• /
• 2012

CIGS 단일 타켓을 DC 및 RF 마그네트론 스퍼터링을 이용하여 파워별로 Mo/SLG위에 증착하여 미세구조 및 화학 조성 평가를 실시하였다. 파워가 증가함에 따라 이온의 운동에너지 증가에 따라서 결정성이 향상되었음을 확인할 수 있었다. DC 마그네트론 스퍼터링의 경우 40W에서 가장 결정성이 좋았으며, RF 마그네트론 스퍼터링은 80W에서 높은 결정성을 확인할 수 있었다. 이는 DC power 40W와 RF power 80W에서 박막의 조성이 화학양론을 만족하고 grain의 성장이 잘 되었기 때문에 높은 결정성을 나타났다고 생각된다.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.2
• /
• pp.85-88
• /
• 2017

In this paper, we have designed and fabricated a RF-DC voltage multiplier for 5.8GHz microwave wireless power transmission. In order to obtain higher voltage, the RF-DC voltage multiplier with 10 diodes (D-10) and the receiver module with an antenna and BPF (Band Pass Filter) was manufactured. The measured and compared results show that the voltages of the proposed one are lower than those of the previous tripler module up to 40cm. However, the voltage of the proposed one with the voltage multiplier is higher than that of the tripler module at the distances of 45cm and 50cm due to the voltage multiplier with 10 diodes.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.4
• /
• pp.68-71
• /
• 2021

In this paper, GaN-SBD devices with excellent breakdown voltage and frequency characteristics for use in high-power microwave wireless power transmission has been modeled for PSpice circuit simulation. The RF-DC conversion circuits were simulated and compared with a commercial Si-SBD device. Although the modeled GaN-SBD devices had lower RF-DC conversion efficiency compared to Si-SBD at 2.4 and 5.8 GHz, it was confirmed through PSpice circuit simulations that they can be used sufficiently according to the required application circuit in a high power situation.