• Journal of Advanced Marine Engineering and Technology
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• v.31 no.8
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• pp.970-974
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• 2007

A mixer is a key component in the wireless communication systems. In this paper, we design a mixer which is used in a frequency modulated continuous wave(FMCW) radar system. The frequency sweep range of the radar is from 10 GHz to 11 GHz. The transmitted and received signals of the FMCW radar are applied to LO and RF ports of the mixer, respectively, but the frequency difference between the two signals, which is called "a beat frequency" is under a few KHz and depending on the distance to target. Thus the isolation between the LO and RF ports is very important factor to design this mixer. In this paper we propose a single balanced resistive mixer using GaAs MESFET for this application. We first design a single-ended type resistive mixer using a simulation tool, then design a balanced type to increase the LO-to-RF isolation of the mixer. We fabricated the mixer on the substrate of dielectric constant 10 and thickness 0.635 mm. The measured results show that the isolation and conversion loss of the mixer over the frequency band is 20dB and 10.5dB, respectively. The LO input power for operating the proposed mixer is +3dBm, which is lower than a general conventional mixer's LO power. The 1 dB compression point is 6dBm.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.827-834
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• 2020

In this paper, a third-order harmonic mixer is designed using frequency multiplier theory for the microwave airborne radar. Unlike the basic mixer design method, the gate bias voltage, at which the third-harmonic component of the Local frequency (LO) is the maximum, is selected using a frequency multiplier theory to maximize the third-harmonic mixing component at the intermediate frequency (IF). The proposed harmonic mixer was designed and manufactured using a commercial GaAs MESFET device in a plastic package, and it was possible to improve the high conversion loss, circuit complexity, high cost, and manufacturing complexity of the existing microwave mixer. The harmonic mixer using the proposed design method has a -8 ~ -10 dB conversion loss by pumping 11.5 GHz LO with a +5 dBm level when operating from 33.0 GHz to 36.0 GHz and the 1-dB gain compression point (P1dB) of 0 dBm.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.539-548
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• 2013

Although Motion estimation (ME) plays an important role in digital video compression, it requires a complicated search procedure to find an optimal motion vector. Multi-view video is obtained by capturing one three-dimensional scene with many cameras at different positions. The computational complexity of motion estimation for Multi-view video coding increases in proportion to the number of cameras. To reduce computational complexity and maintain the image quality, a low complexity motion estimation search method is proposed in this paper. The proposed search method consists of four-grid diamond search patten, two-gird diamond search pattern and TZ 2 Point search pattern. These search patterns exploit the characteristics of the distribution of motion vectors to place the search points. Experiment results show that the speedup improvement of the proposed method over TZ search method (JMVC) can be up to 1.8~4.5 times faster by reducing the computational complexity and the image quality degradation is about to 0.01~0.24 (dB).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.127-132
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• 2018

In this paper, a high conversion gain cascode mixer was designed in W-band and verified by the fabrication and measurements. In the high frequency band such as a W-band, the conversion loss of a mixer is increased because of the poor performance of transistors. This high conversion loss of the mixer requires additional circuits which can give an extra gain such as an RF buffer amplifier, and this can affects the linearity and stability of the overall systems. Therefore, it is necessary to maximize the conversion gain of the mixer. To maximize the conversion gain of the mixer, biases of the transistor were optimized, and output load impedance was optimized by the load-pull simulations. The designed mixer was fabricated in $0.1-{\mu}m$ GaAs pHEMT technology and verified by the measurements. The measurement results shows a maximum conversion gain of -4.7 dB at W-band and an input 1-dB compression point of 2.5 dBm.

• Nuclear Engineering and Technology
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• v.54 no.2
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• pp.661-665
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• 2022

The 3 MeV proton irradiation effects on SiGe low noise amplifier (LNA) (NXP BGU7005) performance under different voltage supply VCC (0 V, 2.5 V) conditions were firstly experimental studied in this present work. The S parameters including S₁₁, S₂₂, S₂₁, 1 dB compression point and noise figure (NF) of the test samples under different bias voltage supply were measured and compared before and after 3 MeV proton irradiation. The total proton irradiation fluence was 1 × 10¹⁵ protons/cm². The maximum degradation quantities of the gain S₂₁ and NF of the test samples under zero bias are measured respectively 1.6 dB and 1.2 dB. Compared with the samples under 2.5 V bias supply, the maximum degradation of S₂₁ and NF are respectively 1.1 dB and 0.8 dB in the whole frequency band. It is noteworthy that the gain and NF of SiGe LNAs under zero-bias mode suffer enhanced degradation compared with those under normal bias supply. The key influence factors are discussed based on the correlation of the SiGe device and the LNA circuit. Different process of the ionization damage and displacement damage under zero-bias and 2.5 V bias voltage supply contributed to the degradation difference. The underlying physical mechanisms are analyzed and investigated.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.159-168
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• 2012

In this paper, a W-band single-chip receiver MMIC for FMCW(Frequency-modulated continuous-wave) radar is presented using $0.15{\mu}m$ GaAs pHEMT technology. The receiver MMIC consists of a 4-stage low noise amplifier(LNA), a down-converting mixer and a 3-stage LO buffer amplifier. The LNA is designed to exhibit a low noise figure and high linearity. A resistive mixer is adopted as a down-converting mixer in order to obtain high linearity and low noise performance at low IF. An additional LO buffer amplifier is also demonstrated to reduce the required LO power of the W-band mixer. The fabricated W-band single-chip receiver MMIC shows an excellent performance such as a conversion gain of 6.2 dB, a noise figure of 5.0 dB and input 1-dB compression point($P_{1dB,in}$) of -12.8 dBm, at the RF frequency of $f_0$ GHz, LO input power of -1 dBm and IF frequency of 100 MHz.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.2
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• pp.10-20
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• 1997

This paper describes the design, the manufacture and the development of th eautomatic gain control unit which ajdusts the gain of IF processor in the high sensitive & multifunctional receiver unit (HMR) for pulse doppler radar system. Accodording to the effective distnce of target, radar cross section, and a lot of external environments (such as clutter), the receiving stage of RADAR system often deviates from dynamic range. To solve this kind o fproblem, continuous/pulse wave AGC are realized, make it possible to control the gain characteristics of receiver stably, and can increase dynamic range linearly by adjusting the gain slope of receiver which is limited by 1-dB gain compression point. In this study, AGC unit is designed to regulate the total gain of receiver by using te analog feedback theory. It also has rapid enough response to process pulse signal. This study presents the gain control method of IF, the real manufacture technique (the package-type components) and the measurement performance of AGC.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.239-244
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• 2004

In this paper, we have developed a frequency mixer which can be used as a microwave phase conjugator in the LS band retrodirective antenna system. The mixer as a phase conjugator must have an If signal of which frequency is nearly as high as that of an RF signal, so this fact brings difficulty in the combination of input signals and the design of impedance matching circuit. The circuit configuration is chosen to be of the gate mixer using a pseudomorphic HEMT device. The operating frequencies are 4.00 ㎓, 2.01 ㎓, and 1.99 ㎓ for LO, RF, and IF, respectively. Conversion gain is measured to be 12.5 ㏈ and 1 ㏈ compression point -34 ㏈m at the LO power of -7 ㏈m. The mixer fabricated in this research is the single-ended type, where RF leakage signal appears inevitably at the If port because RF and If frequencies are almost the same. The circuit topology suggested here can be applied directly to the design of balanced-type mixers and phase conjugators.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.5 s.335
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• pp.61-68
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• 2005

In this paper, low conversion loss 94 GHz MIMIC resistive mixer was designed and fabricated. The $0.1{\mu}m$ InGaAs/InAlAs/GaAs Metamorphic HEMT, which is applicable to MIMIC's, was fabricated. The DC characteristics of MHEMT are 665 mA/mm of drain current density, 691 mS/mm of maximum transconductance. The current gain cut-off frequency(fT) is 189 GHz and the maximum oscillation frequency(fmax) is 334 GHz. A 94 GHz resistive mixer was fabricated using $0.1{\mu}m$ MHEMT MIMIC process. From the measurement, the conversion loss of the 94 GHz resistive mixer was 8.2 dB at an LO power of 10 dBm. P1 dB(1 dB compression point) of input and output were 9 dBm and 0 dBm, respectively. LO-RF isolations of resistive mixer was obtained 15.6 dB at 94.03 GHz. We obtained in this study a lower conversion loss compared to some other resistive mixers in W-band frequencies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1105-1111
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• 2006

In this paper, using low-temperature co-fired ceramic(LTCC) based system-in-package(SiP) technology, a very compact power amplifier LTCC module was designed, fabricated, and then characterized for 60 GHz wireless transmitter applications. In order to reduce the interconnection loss between a LTCC board and power amplifier monolithic microwave integrated circuits(MMIC), bond-wire transitions were optimized and high-isolated module structure was proposed to integrate the power amplifier MMIC into LTCC board. In the case of wire-bonding transition, a matching circuit was designed on the LTCC substrate and interconnection space between wires was optimized in terms of their angle. In addition, the wire-bonding structure of coplanar waveguide type was used to reduce radiation of EM-fields due to interconnection discontinuity. For high-isolated module structure, DC bias lines were fully embedded into the LTCC substrate and shielded with vias. Using 5-layer LTCC dielectrics, the power amplifier LTCC module was fabricated and its size is $4.6{\times}4.9{\times}0.5mm^3$. The fabricated module shows the gain of 10 dB and the output power of 11 dBm at P1dB compression point from 60 to 65 GHz.