• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.1
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• pp.26-32
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• 1994

In this paper, using the newly developed GaAs Schottky beam-lead diode made by Marconi company, we have developed and evaluated the waveguide type single-ended mixer at Q-band. The various components of the mixer were separately designed and optimized using the Super-Compact software. These studies included the design of the step waveguide impedance transformer and the RF-choke filter, and the optimization of a high and low impedance for the RF-choke filter. Moreover, this RF-choke filter pattern included a section to reject the second harmonic frequency of the RF signal. Finally, this Q-band mixer with 1.4GHz/400MHz IF frequency exhibits an average conversion loss of 5.3 dB over 33-50GHz bandwidth.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.154-157
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• 2000

One of the problems using DCR(Direct Conversion Receiver) type architecture are DC offset, Poor channel selectivity. APDP(Anti Parallel Diode Pair) can be mood candidate for the DCR frequency mixer due to its inherent 2nd harmonic suppression. APDP shows good IP2 and DC suppression. This paper describes single APDP LO power characteristics, IP2, and receiver structure utilizing APDP frequency mixer.

• Tribology and Lubricants
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• v.35 no.1
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• pp.71-76
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• 2019

The differential planetary gear reducer as a main component of the concrete mixer driving mechanism requires a strong torque to mix concrete compounds. As this component is currently dependent on imports, it is necessary to develop it by conducting a study on vibration analysis and the resonance problem. The noise and vibration of a concrete mixer reducer increase owing to the transmission error of planetary gears, and the damage of components occurs owing to the problems in design and production. In this study, the tooth-passing frequency is calculated to evaluate the noise and vibration of a mixer reducer, and a fast Fourier transform (FFT) analysis is conducted through a vibration test using an acceleration sensor. The vibration of the reducer is measured at three points of input and output of the shaft and planetary gear housing with fixed and variable revolutions per minute. The operating conditions of gears and bearings are evaluated by performing the FFT analysis, and the resonance problem is verified. The results show that No. 1 pinion and ring gears revolve disproportionately. The amplitude values appear high, and the wear of tooth faces occur in tooth-passing frequencies and harmonic components of No. 1 and No. 2 pinion-ring gears. Therefore, we conclude that design changes in the reducer and a correction of tooth profiles are required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.682-690
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• 2012

In this paper, a highly linear self oscillating mixers(SOM) using second harmonic injections are presented. The H-slot defected ground structure(DGS) is designed as a balanced resonator for oscillation in the proposed SOM. Since the H-slot DGS resonator achieves a high Q factor, it is a suitable structure to provide low phase noise for the oscillator. The single balanced mixer is utilized in this work and it provides good LO-RF isolation since balanced LO signals are suppressed at the RF input port. In order to inject the second harmonic of the IF, we propose two different methods using feedback loops. In the first method, IF achieves a 3.08 dB conversion gain at 226 MHz with input power of -20 dBm at 5 GHz RF input signal. The IF achieves 2 dB conversion gain at 423 MHz with the input power of -20 dBm at 5.2 GHz RF input signal in the second method. The measured IMD3s are 61.8 dB and 65 dB for the each method. These SOMs present improved linearity compared to that without the second harmonic injection because IMD3s are improved by 18. dB and 21 dB for each method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.71-76
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• 2010

In this paper, a 120 GHz local oscillator(LO) for the sub-harmonic mixer in the THz transceiver with a carrier frequency of 240 GHz was designed and fabricated. A 120 GHz local oscillator was composed of 40 GHz PLL(Phase Locked Loop), 40 GHz BPF(Band Pass Filter), frequency tripler and 120 GHz BPF. The commercial model of the frequency tripler was used. The measured result of the 40 GHz PLL showed the phase noise of -105 dBc/Hz at the 100 kHz offset frequency. The measured result of 120 GHz BPF showed the insertion loss of 1.3 dB at center frequency of 119 GHz with bandwidth of 5 GHz. The output power of 120 GHz LO was measured to 6.6 dBm.

• The Journal of the Korea Contents Association
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• v.6 no.4
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• pp.1-10
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• 2006

In this paper, a broadband RF module is designed and tested for 2.4GHz band applications. The RF module is composed of a low noise amplifier (LNA) with a three stage amplifier, a single ended gate mixer, matching circuits, a hairpin line band pass filter and a Chebyshev low pass filter to convert the radio frequency (RF) into the intermediate frequency (IF). The LNA has a high gain and stability, and the single ended gate mixer has a high conversion gain and wide dynamic range. In the analysis of the broadband RF module, the composite harmonic balance technique is used to analyze the operating characteristics of an RF module circuit. The RF module has a 55.2dB conversion gain with a 1.54dB low noise figure, $-120{\sim}-60dBm$ wide RF power dynamic range, -60dBm low harmonic spectrum and a good isolation factor among the RF, IF, and local oscillator (LO) ports.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.7 s.98
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• pp.681-689
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• 2005

This paper presents an ultra wide band(UWB) mixer using anti-parallel diode pair(APDP) with simulation and measurement results. The proposed mixer adopts the even-harmonic direct conversion mixing, which consists of a couple of filter, in-phase wilkinson power divider, wideband $45^{\circ}$ power divider, and APDP. The m mixer is operating over 3.1 to 4.8 GHz and producing quadrature(I/Q) outputs with a conversion loss of 18 dB and input third order intercept point($IIP_3$) of 15 dBm. I/Q outputs also have difference of about 0.5 dB and phase difference of ${\times}3^{\circ}$ and $P_{1dB}$ of 2 dBm.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.875-879
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• 2004

In this paper, sub-harmonic pumped(SHP) mixer using anti-parallel diode pair(APDP) is designed for 5 GHz band wireless communication system. Conventional mixers mix LO with RF, and obtain IF signal from the difference between LO and RF. As the frequency increase, LO signal requires higher LO power, better phase noise characteristics, more stable La. However, using APDP, the SHP mixer mixes the 2nd harmonics of LO signal. Therefore, the SHP mixer has an advantage that the LO signal frequency required for IF signal is reduced at half value of LO fundamental frequency. When LO power is 3 dBm, the conversion loss of manufactured SHP mixer is 12.83 dB. The isolation of LO/IF, 2LO/IF, RF/1F and LO/RF is 39.17 dB, 58 dB, 34 dB, and 67.9 dB. respectively. For this case, IP3 at input is 8 dBm.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2811-2816
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• 2007

We conducted a numerical study of AC-electroosmotic (alternating current) effect on the fluid flow and mixing in a 3-D microchannel. The microchannel used as an efficient micro-mixer is composed of a channel and a series of pairs of electrodes attached in zigzag pattern on the bottom wall. The AC electric field is applied to the electrodes so that a steady flow current takes place around the electrodes. This current is flowing across the channel and thus contributing to the mixing of the fluid within the channel. We performed numerical simulations by using a commercial code to obtain a steady flow field. This steady flow is then used in evaluation of the mixing performance via the concept of mixing index. It was found that good combination of two kinds of electrode, which gave us a good mixing, is not simple harmonic. And when the length ratio of these two kinds of electrode is 2:1, we can get the best mixing effect.