• Transactions on Electrical and Electronic Materials
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• v.17 no.5
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• pp.261-269
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• 2016

A high-performance transmit/receive (T/R) switch is essential for every radio-frequency (RF) device. This paper proposes a T/R switch that is designed in the CEDEC 0.13 μm complementary metal-oxide-semiconductor (CMOS) technology for 2.4 GHz ISM-band RF applications. The switch exhibits a 1 dB insertion loss, a 28.6 dB isolation, and a 35.8 dBm power-handling capacity in the transmit mode; meanwhile, for the 1.8 V/0 V control voltages, a 1.1 dB insertion loss and a 19.4 dB isolation were exhibited with an extremely-low power dissipation of 377.14 μW in the receive mode. Besides, the variations of the insertion loss and the isolation of the switch for a temperature change from - 25℃ to 125℃ are 0.019 dB and 0.095 dB, respectively. To obtain a lucrative performance, an active inductor-based resonant circuit, body floating, a transistor W/L optimization, and an isolated CMOS structure were adopted for the switch design. Further, due to the avoidance of bulky inductors and capacitors, a very small chip size of 0.0207 mm² that is the lowest-ever reported chip area for this frequency band was achieved.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.12
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• pp.24-29
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• 2009

In order to model the high temperature dependence of the cutoff frequency $f_T$ in $0.18{\mu}m$ deep n-well isolated bulk NMOSFET, high temperature data of electron velocity of bulk MOSFETs from $30^{\circ}C$ to $250^{\circ}C$ are obtained by an accurate RF extraction method using measured S-parameters. From these data, an improved temperature-dependent electron velocity equation is developed and implemented in a BSIM3v3 SPICE model to eliminate modeling error of a conventional one in the high temperature range. Better agreement with measured $f_T$ data from $30^{\circ}C$ to $250^{\circ}C$ are achieved by using the SPICE model with the improved equation rather than the conventional one, verifying its accuracy of the improved one.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.2
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• pp.143-152
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• 2019

In this paper, we described the design of Ka-band planar active phased array antenna which is applicable for small RADAR for airborne and seeker of guided missile. The antenna consists of about 1000 array radiating elements and is designed to be within 200mm diameter. We optimized the spacing of radiating elements to allow beem steering above ${\pm}55$ degrees of Field of view, and analyzed the performance of antenna. We confirmed that the Effective Isotropic Radiated Power (EIRP) of the antenna can be 94.22 dBm and receive G/T can be 1.68 dB/k through the designs of RF components and the verification of RF budget. The TX output of TR Module is designed to be over 1.3W for EIRP, and Receive noise figure of TR Module is designed to be less than 5dB for G/T.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.436-440
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• 2021

The impact of the gate length (L_g) on the DC and high-frequency characteristics of indium-rich In_0.8Ga_0.2As channel high-electron mobility transistors (HEMTs) on a 3-inch InP substrate was inverstigated. HEMTs with a source-to-drain spacing (L_SD) of 0.8 ㎛ with different values of L_g ranging from 1 ㎛ to 19 nm were fabricated, and their DC and RF responses were measured and analyzed in detail. In addition, a T-shaped gate with a gate stem height as high as 200 nm was utilized to minimize the parasitic gate capacitance during device fabrication. The threshold voltage (V_T) roll-off behavior against L_g was observed clearly, and the maximum transconductance (g_{m_max}) improved as L_g scaled down to 19 nm. In particular, the device with an L_g of 19 nm with an L_SD of 0.8 mm exhibited an excellent combination of DC and RF characteristics, such as a g_{m_max} of 2.5 mS/㎛, On resistance (R_ON) of 261 Ω·㎛, current-gain cutoff frequency (f_T) of 738 GHz, and maximum oscillation frequency (f_max) of 492 GHz. The results indicate that the reduction of L_g to 19 nm improves the DC and RF characteristics of InGaAs HEMTs, and a possible increase in the parasitic capacitance component, associated with T-shap, remains negligible in the device architecture.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1666-1668
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• 2004

By wireless transmission data, there is high possibility to get distortion and lose by noise and barrier on wireless. If the data check damaged and lost at receiver, can't make it clear and can't judge whether this data is right or not. Therefore, by wireless transmission data need the data error check algorithm in order to decrease the data's distortion and lose and to monitoring the transmission data as real time. This study consists of RF station for wireless transmission, Water Level Meter station for water level measurement and Error check algorithm for error check of transmission data. This study is also that investigation and search for error check algorithm in order to wireless digital data transmission in condition of the least data's damage and lose. Designed transmitter and receiver with one - chip micro process to protect to swell the volume of circuit. Had designed RF transmitter - receiver station simply by means of ATMEL one - chip micro process in the systems. Used 10mW of the best RF power and 448MHz-449MHz on frequency band which can get permission to use by Frequency Law made by Korean government

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.993-997
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• 2004

A data error inspection algorithm for wireless digital data communication was developed. Original data converted By wireless digital data error inspection algorithm. Wireless digital data is high possibility to get distortion and lose by noise and barrier on wireless. If the data check damaged and lost at receiver, can't make it clear and can't judge whether this data is right or not. Therefore, by wireless transmission data need the data error inspection algorithm in order to decrease the data distortion and lose and to monitoring the transmission data as real time. This study consists of RF station for wireless transmission, Water Level Meter station for water level measurement and Error inspection algorithm for error check of transmission data. This study is also that investigation and search for error inspection algorithm in order to wireless digital data transmission in condition of the least data's damage and lose. Designed transmitter and receiver with one - chip micro process to protect to swell the volume of circuit. Had designed RF transmitter - receiver station simply by means of ATMEL one - chip micro processing the systems. Used 10mW of the best RF power and 448MHz-449MHz on frequency band which is open to public touse free within the limited power.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.6-12
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• 1995

High Tc superconducting YBa$_{2}$Cu$_{3}$$O_{7-x}$ thin films were prepared on various substrates by off-axis rf magnetron sputtering method to examine the substrate effects on the film structure and its R-T characteristics. The SEM analysis showed that the surface morphology of the grown YBa$_{2}$Cu$_{3}$O.sub 7-x/, film has different characteristic structure with different substrate used. The film on (100) SrTiO$_{3}$ substrate has critical current density of 3*10$^{5}$ A/cm$^{2}$ at 77K under zero magnetic field. The X-ray diffraction measurements revealed that the films on (100) SrTiO$_{3}$ substrate have mixed a-axis and c-axis normal to the substrate surface and the films on (100) MgO and ZrO$_{2}$/sapphire substrates have c-axis normal orientation to the substrate surface. However, YBa$_{2}$Cu$_{3}$$O_{7-x}$ films on (100) sapphire substrates showed no preferential orientation.ion.

• Korean Journal of Materials Research
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• v.12 no.4
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• pp.290-295
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• 2002

Microstructure and electrical properties of $In_2O_3$ transparent thin films are analyzed on the basis of Structure Zone Model (SZM) proposed by Thornton. Thin films are deposited on glass substrate by RF magnetron sputtering with variation of substrate temperature $(T_s)$ and argon gas pressure $(P_{Ar})$. Microstructure of Zone I of SZM is observed with lowering of substrate temperature or increasing of argon pressure. The higher electrical resistivity of those specimens is due to micro-pores or voids between columnar grains. At the conditions of $T_s=450^{\circ}C$ and $P_{Ar}$=4.2mTorr, the Zone II structure of SZM and the lowest electrical resistivity $(2.1{\times}10^{-2}{\Omega}cm)$ are observed. The dense structure of columnar grains with faceting on growing surface and preferred orientation of (100) plane are observed in those specimens.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.8
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• pp.319-324
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• 2003

AIN thin films are deposited on Si (100) and $SiO_2$/Si substrates by using an RF magnetron sputtering method and by changing the conditions of deposition variables, such as RF power, $N_2$/Ar flow ratio, and substrate temperature ($T_sub$). For all the deposited AIN films, XRD Peak patterns are monitored to examine the effect of deposition condition on the crystal orientation. Highly (002)-oriented AIN films are obtained at following nominal deposition conditions; RF Power : 350W, $N_2$/Ar ratio = 10/20, T$_{sub}$ : $250^{\circ}C$, and working pressure = 5mTorr, respectively. AIN-based SAW devices are fabricated using a lift-off method by varying the thickness of AIN layer. Insertion losses and side-lobe rejection levels of fabricated SAW devices are extracted from their frequency response characteristics, which are also compared in terms of AIN thickness and substrate. Relationships between the film properties of AIN films and the frequency responses of SAW devices are discussed. It is concluded from the experimental results that the (002)-preferred orientation as well as the surface roughness of AIN film may play a crucial role of determining the device performances of AIN-SAW devices.s.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.31-36
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• 1998

In this paper, Image Rejection Interdigital Filter(IRIF) for 5.8GHz wireless LAN was designed and implemented. When the input signal is -30dBm in the 4~8㎓ frequency band, the insertion loss including all kinds of loss is 6.3dB in the center frequency 5.775GHz. Therefore, it was showed practically insertion loss of about -3.3dB. Especially, image signal rejection is about -l7dB in the image frequency 6.475GHz. and skirt characteristics of the high frequency band is very excellent. Therefore, it was confirmed that the proposed IRIF is suitable for RF image signal rejection in the 5.8GHz wireless LAN system.