• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1143-1150
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• 2001

In this paper, we designed a downconverter for K-band satellite multipoint distribution service(SMDS). The designed downconverter consists of a low noise amplifiers, bandpass filter, stable local oscillator, drain mixer and If Amplifiers. Low noise amplifiers show 28㏈ gain and 1.5㏈ noise figure in the frequency range of 19.2㎓~20.2㎓, and a band pass filter has a -l㏈ insertion loss, and 18.25㎓ Stable local oscillator which is dielectric resonant oscillation, We obtained that the output power of the 18.25㎓ oscillation frequency is 0.5㏈m and the phase noise is the -84.67㏈c at 10KHz offset frequency. With the input RF signal the 19.2㎓~20.2㎓, conversion gain of the drain mixer shows 5㏈ at the Intermediate frequency range of 950MHz~1950MHz. We have proved that the designed downconverter satisfied the specification of a K-band satellite multipoint distribution service and it can be applied to the satellite internet receiver.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1120-1128
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• 2004

In this paper, we has designed and implemented Up-converter for K-band with high IMD3 performance using balanced power amplifier. It is consisted of PA module and, Local Oscillator module with reject Filter, mixer module and If block, and Up-converter has a local loop path to decide whether it operate or not and has the sensing port to inspect output power level. According to the power budget of designed Up-converter, K-band balanced power amplifier was fabricated by commercial MMIC. Measurement results of up-converter show about 40dB Gain, PldB of 29dBm and OIP3 was 38.25dBm, that is good performance compared to power budgets. We has adjusted gate voltage of MMIC to control more than 30 dB gain. This up-converter was used in transceiver for PTP and PTMP, and applied to digital communication system that use QAM and QPSK modulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1318-1323
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• 2010

A lot of demand for parts of millimeter wave band, as would be expected 57~63 GHz band down conversion mixer was designed and fabricated using IHP 0.25 um SiGe process. Designed and fabricated mixer was double balanced type and located reduced 3D balun at RF port and buffer amplifier at outport for suppression LO signal and conversion gain. Fabricated mixer measured conversion gain of 13.8 dB, $P1dB_{in}$ -17 dBm and 88 mA of current consumption characteristics, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.137-140
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• 2008

본 논문에서는 높은 주파수에서 이미지신호에 따른 하향변환기의 선현성을 우수하게 나타내기 위하여 이미지 제거 특성이 우수한 능동소자를 선택하여 VSAT 위성통신용 Ka-band 하향변환기를 설계 및 제작하였다. 하향변환기의 구성은 저잡음 증폭기단, 이미지 제거 필터, 주파수 혼합기, 주파수 체배기, 전압제어 감쇄단 및 IF단으로 구성하였고, RF 경로의 동작 유무를 판단하기 위하여 국부 루프 경로로 구성되어 있다. 하향변환기의 이득은 $11.73{\sim}13.23dB$, 잡음지수 4.4dB 이하, 50dBc 이상의 이미지 제거 특성을 나타내어, 본 논문에서 제작한 하향변환기는 고속/광 대역폭을 가지는 디지털 통신 시스템에도 적용할 수 있다.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.89-92
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• 2008

CMOS 기반의 고주파 집적회로에서는 높은 이득과 출력을 얻기 위하여 인덕터와 같은 수동소자를 사용한다. 그러나 수동소자를 사용하게 되면 넓은 면적을 차지하기 때문에 회로의 크기를 증가시키는 단점을 갖는다. 본 논문에서는 PMOS 를 기반으로 구현한 active inductor 를 적용하여 회로의 면적을 줄일 수 있으며, 기존의 주파수 변환기와 동등한 선형 특성을 갖는 상향 주파수 변환기를 설계하였다. 인덕터를 적용한 상향 주파수 변환기의 OIP3 ($3^{rd}$ Output Intercept Point)는 1.3 dBm 을 가지며, 제안한 상향 주파수 변환기의 OIP3 는 0.8 dBm 으로 동등한 선형 특성을 보이며, layout 상에서 회로의 면적을 40 % 이상 감소하는 특성의 선형 송신기용 주파수 변환기를 설계 분석하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.196-199
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• 2000

In this paper, we have designed a low-noise amplifier for the down-converter to apply the K-band Mu-kung-hwa satellite downconvertion. We have designed on three-stage to satisfy the property of low-noise amplifier for the down-converter required at least 30dB gain. The simulaition results for the designed three-stage Low-noise amplifier are measured that 33dB, gain and 0.93dB, noise-figure From 19.200 to 20.200, and The experiment results of the fabric are measured that 25dB, gain and 1.5dB, noise-figure. Since Input reflection coefficient and otput resection coefficient are -25dB and -28dB, respectively, and VSWR is lower than 1.5, this amplifier can be used as a low-noise amplifier for the down-converter to apply the K-band Mu-kung-hwa satellite downconvertion.

• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.238-246
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• 2017

High frequency ultrasound imaging typically suffers from low sensitivity due to the small aperture of high frequency transducers and shallow imaging depth due to the frequency-dependent attenuation of ultrasound. These limitations should be overcome to obtain high-frequency, high- resolution ultrasound images. One practical solution to the problems is a high-performance signal receiver capable of detecting a very small signal and amplifying the signal with minimal electronic noise addition. This paper reports a recently developed low-noise, wideband ultrasound receiver for high-frequency, high-resolution ultrasound imaging. The developed receiver has an amplification gain of up to 73 dB and a variable amplification gain range of 48 dB over an operating frequency of 80 MHz. Also, it has an amplification gain flatness of ${\pm}1dB$. Due to these high performances, the developed receiver has a signal-to-noise ratio of at least 8.4 dB and a contrast-to-noise ratio of at least 3.7 dB higher than commercial receivers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.85-90
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• 2008

Effects of the emitter degeneration on linearity have been investigated in SiGe HBT double-balanced up-converters with the Gilbert-cell structure. The emitter-coupled degeneration resistors have been optimized for high P1-dB and IP3 through the nonlinear harmonic-balance simulation. Two types of up-converter MMICs fabricated in $0.35{\mu}m$ Si-BiCMOS process were measured to verify the simulation results. The up-converter without the degeneration resistors produces a P1-dB of -13 dBm with an OIP3 of 3.7 dBm, while the up-converter with the degeneration resistors produces a P1-dB of -10 dBm with an OIP3 of 8.7 dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.12
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• pp.1167-1172
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• 2013

This paper presents a X-band doppler radar with high conversion gain using a self-oscillating-mixer(SOM) that oscillation and frequency mixing is realized at the same time. To improve phase noise of the SOM oscillator, a ${\lambda}/2$ slotted square patch resonator(SSPR) was proposed, which shows high Q-factor of 175.4 and the 50 % reduced circuit area compared to the conventional resonator. To implement the low power system, low biasing voltage of 1.7 V was supplied. To enhance the conversion gain of the SOM, bias circuit is configured near the pinch-off region of transistor, and the conversion gain was optimized. The output power of the proposed SOM was -3.16 dBm at 10.65 GHz. A high conversion gain of 9.48 dB was obtained whereas DC Power consumption is relatively low about 7.65 mW. The phase noise is -90.91 dBc/Hz at 100 kHz offset. The figure-of-merit(FOM) of the proposed SOM was measured as -181.8 dBc/Hz, which is supplier to other SOMs by more than about 7 dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.5
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• pp.197-203
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• 2003

In this paper, we have presented millimeter-wave high conversion gain quadruple subharmonic mixers adopting the cascode harmonic generator The subharmonic mixers were successfully integrated by using 0.1 ${\mu}{\textrm}{m}$ GaAs pseudomorphic HEMTs(PHEMTs) and coplanar waveguide(CPW) structures. Measured output of 1st, 2nd and 4th harmonics of the fabricated cascode 4th harmonic generator are -21.42 dBm, -32.65 dBm and -13.45 dBm, respectively, for an input power of 10 dBm at 14.5 GHz. We showed that the highest conversion gain of 3.4 dB has obtained thus far at a LO power of 13 dBm from the fabricated subharmonic mixers. The millimeter-wave subharmonic mixer also ensure a high degree of isolation showing -53.6 dB in the LO-to-IF and -46.2 dB in the LO-to-RF, respectively, at a frequency of 14.5 GHz. The high conversion gain achieved in this work is the first report among the millimeter-wave subharmonic mixers.