• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.16-24
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• 2009

Independent-gate-mode double-gate(IGM-DG) MOSFET overcomes the limitation of 3-terminal device structure, and enables to operate with different voltages for front-gate and back-gate. Therefore, circuit designs becomes not only simple, but also area-efficient due to the controllability of the 4th terminal provided by IGM-DG MOSFETs. In this paper, an RF receiver utilizing IGM-DG MOSFETs is presented and also, the circuit performance is verified by the HSPICE simulations. Besides, the circuit analysis and optimization are performed for various IGM-DG characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.209-209
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• 2007

Passive Device는 RF Circuit을 제작할 때 많은 면적을 차지하고 있으며 이를 감소시키기 위해 여러 연구가 진행되고 있다. 최근 SoP-L 공정을 이용한 많은 연구가 진행되고 있는데 PCB 제작에 이용되는 일반적인 재료와 공정을 그대로 이용함으로써 개발 비용과 시간 면에서 많은 장점을 가지기 때문이다. SoP-L의 또 하나 장점은 다층구조를 만들기가 용이하다는 점이다. 각 층 간에는 Via를 사용하여 연결하게 되는데, RF Circuit은 회로의 구조와 물성에 따라 특성이 결정되며, 그만큼 Via를 썼을 때 그 영향을 생각해야 한다. 본 연구에서는 multi-layer LCP substrate에 다수의 Via를 chain 구조로 형성하여 전기적 특성을 확인하였다. Via가 70um 두께의 substrate를 관통하면서 상층과 하층의 Conductor을 연속적으로 연결하게 된다. 이 구조의 Resistance와 Insertion Loss를 측정하여, Via의 크기 별 수율과 평균적인 Resistance, RF 계측기로 재현성을 확인하였다. 이를 바탕으로 공정에서의 안정성을 확보하고 Via의 크기와 도금방법에 의한 RF Circuit에서의 영향을 파악하여, 앞으로의 RF Device 개발에 도움이 될 것으로 기대한다. 특히 유기물을 이용한 다층구조의 고주파 RF Circuit에 Via를 적용할 때의 영향을 설계에서부터 고려할 수 있는 자료가 될 것이다.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1673-1675
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• 2004

The design, modeling and measurement of RF switch module for GSM applications is presented in this paper. RF switch module is constructed using a LTCC multi-layer switching circuit and integrated low pass filter. Insertion and return loss of the low pass filter were designed less than 0.3 dB and better than 12.7 dB at 900 MHz. The RF switch module contained 10 embedded passives and 3 surface mount components integrated on $4.6{\times}4.8{\times}1.2$ mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module was measured at 900 MHz was 11 dB.

• Carbon letters
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• v.13 no.1
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• pp.17-22
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• 2012

Currently, graphene is a topic of very active research in fields from science to potential applications. For various radio-frequency (RF) circuit applications including low-noise amplifiers, the unique ambipolar nature of graphene field-effect transistors can be utilized for high-performance frequency multipliers, mixers and high-speed radiometers. Potential integration of graphene on Silicon substrates with complementary metal-oxide-semiconductor compatibility would also benefit future RF systems. The future success of the RF circuit applications depends on vertical and lateral scaling of graphene metal-oxide-semiconductor field-effect transistors to minimize parasitics and improve gate modulation efficiency in the channel. In this paper, we highlight recent progress in graphene materials, devices, and circuits for RF applications. For passive RF applications, we show its transparent electromagnetic shielding in Ku-band and transparent antenna, where its success depends on quality of materials. We also attempt to discuss future applications and challenges of graphene.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1567-1570
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• 2022

This paper, we presents a RF protection technique of antenna switch by improving the power handling capability in worst case environment mode for mobile phone applications without critical payment of circuit performances such as insertion loss, isolation and ACBV (AC breakdown voltage). By applying a additional capacitive path located in front of the antenna in cell-phone, it performs the effective reduction of input power in high voltage standing wave ratio (VSWR) condition. Under the all-path off condition which causes a high VSWR, it achieved 37.7dBm power handling level as high as 5.7dB compared to that of conventional one at 2GHz. In addition, insertion loss and isolation performances were 0.31dB and 42.72dB at 2 GHz, respectively which were almost similar to that of the conventional circuit. The proposed antenna switch was fabricated in 130nm CMOS SOI technology.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.72-77
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• 2013

The effect of sputtering condition on the structural properties of ZnO thin films grown by RF magnetron sputtering system was investigated for TFT driver circuit. ZnO thin films were grown with ZnO target varying RF power and working pressure. Structural properties were investigated by X-ray diffraction (XRD) and atomic force microscope (AFM). The ZnO thin films have sufficient crystallinity on the 100W RF power. But, the surface roughness of ZnO films was increased as increased RF power. As increased working pressure from 5 mTorr to 15 mTorr, a full width at half maximum (FWHM) of ZnO (002) peak was increased.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.19-26
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• 2006

The ccrf-discharge has in comparison with the hollow-cathode discharge and DC-discharge some advantages: Simple design of the tube and homogeneous plasma. The ccrf-discharge was researched with the goal, to use on the excitation of the gas laser. In this work a rf-exciting system was planned and developed. With it a homogeneous discharge was produced in the cw operation. To supply the rf-power with the frequency 13.56[MHz] effectively in the discharge, laser tube were used with inner diameter of 5[mm] and the specially developed rf-electrodes. A matching circuit was composed also. Thereby the impedance of the discharge tube was adjusted to the 50[$\Omega$] output resistance of the rf-source.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.237-240
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• 2002

We have studied a RF energy transformation. In this paper, we introduced proximity sensor using RF energy transformation. We used 125kHz RF signal as carrier frequency and BPSK circuit, PNP proximity sensor and designed circuit to transmit to the reader through the antenna with data which sensor had acquired. Micro-controller, oscillator, power amp, FSK Modulation module are included in the circuit. Max 323 chip is applied to analog switch and used to HYP-30R10NA sensor chip.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.2127-2130
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• 2008

In this paper, a tunable bandpass filter with mutual inductive coupling circuits is newly designed and demonstrated for UHF TV tuner ranged from Ch.14(473MHz) to Ch.69(803MHz) applications. Conventional HF tuning circuit with an electromagnetic bandpass filter has several problems such as large size, high volume and high cost, since the electromagnetic filter is comprised of several passive components and air core inductors to be assembled and controlled manually. To address these obstacles, peaking chip inductor was newly applied for constructing the mutual inductive coupling circuit. The proposed circuit was newly and optimally designed, since the chip inductor showed lower components Q-value than the air core inductor. A varactor diode has been also used to fabricate the proposed tunable bandpass filter for RF tuning circuit. The fabricated tunable filter exhibited low insertion loss of approximately -3dB, high return loss of below -10dB, and large tuning bandwidth of 330MHz.

• Journal of Advanced Navigation Technology
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• v.14 no.5
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• pp.655-660
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• 2010

This paper examines RF-to-DC conversion efficiency of rectifying circuit for wireless power transmission. The rectifying circuit consists of low pass filter, diode circuits and dc pass filter. All these components may be effect on the conversion efficiency. Using the simulation, we study these components how to effect on the conversion efficiency. On the basis of the simulation results, the 912MHz rectifying circuit with 50% efficiency at low input power such as 0dBm is fabricated and its characteristics are measured.