• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.97-101
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• 2003

A MMIC (monolithic microwave integrated circuit) mixer chip using the Schottky diode of an InGahs/CaAs p-HEMT process has been developed for the receiver down converter of Ku-band. A different approach to the MMIC mixer structure is applied for reducing the chip size by the exchange of ports between If and LO. This MMIC covers with RF (14.0 - 14.5 GHz) and If (12.252 - 12.752 GHz). According to the on-wafer measurement, the miniature (3.3X3.0 m) MMIC mixer demonstrates conversion loss below 9.8 dB, RF-to-IF isolation above 23 dB, LO-to-IF isolation above 38 dB, respectively.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.9
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• pp.9-18
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• 1998

A single RF transceiver chip for an extended GSM handset application was designedm, fabricated and evaluated. A RFIC was fabricated by using silicon BiCMOS process, and then packaged in 80 pin TQFP of $10 {\times} 10 mm^{2}$ in size. As a result, it was achieved guite reasonable integraty and good RF performance at the operation voltage of 3.3V. This paper describes development results of RF receiver section of the RFIC, which includes LNA, down conversion mixer, AGC, switched capacitor filter and down sampling mixer. The test results show that RF receiver section is well operated within frequency range of 925 ~960 MHz, which is defined on the extended GSM specification (E-GSM). The receiver section also reveals moderate power consumption of 67 mA and minimum detectable signal of -105 dBm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.538-544
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• 2011

This paper presents a compact single balanced diode mixer fabricated using a 0.1 ${\mu}M$ GaAs p-HEMT commercial process for an E-band frequency up/down converter. This mixer includes a LO balun employing a Marchand balun with a good RF performance. In order to improve the port-to-port isolation, a high pass filter and a low pass filter are include in this mixer at the RF and IF ports, respectively. The fabricated mixer with a very compact size of 0.58 mm2(0.85 mm${\times}$0.68 mm) exhibits a conversion loss of 8～12 dB and an input P1dB of 1～5 dBm at the LO power of 10 dBm from 71～86 GHz.

• Journal of electromagnetic engineering and science
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• v.9 no.2
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• pp.98-104
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• 2009

An InGaP/GaAs MMIC LC VCO designed with Harmonic Noise Frequency Filtering(HNFF) technique is presented. In this VCO, internal inductance is found to lower the phase noise, based on an analytic understanding of phase noise. This VCO directly drives the on-chip double balanced mixer to convert RF carrier to IF frequency through local oscillator. Furthermore, final power performance is improved by output amplifier. This paper presents the design for a 1.721 GHz enhanced LC VCO, high power double balance mixer, and output amplifier that have been designed to optimize low phase noise and high output power. The presented asymmetric inductance tank(AIT) VCO exhibited a phase noise of -133.96 dBc/Hz at 1 MHz offset and a tuning range from 1.46 GHz to 1.721 GHz. In measurement, on-chip down-converter shows a third-order input intercept point(IIP3) of 12.55 dBm, a third-order output intercept point(OIP3) of 21.45 dBm, an RF return loss of -31 dB, and an IF return loss of -26 dB. The RF-IF isolation is -57 dB. Also, a conversion gain is 8.9 dB through output amplifier. The total on-chip down-converter is implanted in 2.56${\times}$1.07 mm$^2$ of chip area.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.86-90
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• 2003

A flat conversion loss in microwave mixer is hard to achieve if integrating with an image rejection filter(IRF). This is due to the change of termination condition with respect to the LO and IF frequency at RF port where the filter has 50 ohm termination property only in the RF band. This paper describes a flatness maintenance in the down mixer concerning a diode matching condition as well as an electrical length of embedding line at RF port. The implemented single balance diode mixer is suitable for a 23 ㎓ European Terrestrial Radio. RF, LO and fixed IF frequency chosen in this paper are 21.2∼22.4 ㎓, 22.4∼23.6 ㎓ and 1.2 ㎓, respectively. The measured results show a conversion loss of 8.5 ㏈, flatness of 1.2 ㏈ p-p, input P1㏈ of 7㏈m, IIP3 of 15.42 ㏈m with nominal LO power level of 10㏈m. The return loss of RF and LO port are less than - 15 ㏈ and - 12 ㏈, respectively and IF port is less than - 6 ㏈. LO/RF and LO/IF isolation are 18 ㏈ and 50 ㏈, respectively. This approach would be a helpful reference for designing up/down converter possessing a filtering element.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.261-264
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• 2005

This paper presents the design of a down-conversion mixer with built-in active balun integrated in a $0.25\;{\mu}m$ pHEMT process. The active balun consists of series-connected common-gate FET and common-source FET. The designed balun achieved broadband characteristics by optimizing gate-width and bias condition for the reduction in parasitic effect. From DC to more than 6GHz, the active balun shows the phase error of less than 3 degree and the gain error of less than 0.4 dB. A single-balanced down-conversion mixer with built-in broadband active balun has been designed with optimum width, load resistor and bias for conversion gain and without any matching component for broadband operating. The designed mixer whose size of including on-chip bias circuit is $1\;mm{\times}1\;mm$ shows the conversion gain of better than 7 dB from 2 GHz to 6 GHz and $P_{1dB}$ of -10 dBm at 5.8 GHz

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1733-1740
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• 2001

A monolithic 5 GHz image reject mixer using a 0.5-m GaAs MESFET technology is designed and simulated. The Mixer exhibits a 13.56 dB down-conversion gain, a SSB (Single SideBand) noise figure of 11.91 dB, an input IP3 (third order intercept point) of -3.73 dBm and a PldB (1-dB compression point) of -11.0 dBm. The critical issue in the image reject mixer is the phase accuracy and magnitude balance of the 90 phase shifting network. The proposed image reject mixer realizes a 90 phase shifter on chip. This phase shifting network does not need any phase adjusting to achieve the phase error specification of 3 over a frequency range from 800 MHz to 1GHz. The simulated overall image rejection ratio is better than 50 dB.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.170-177
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• 2020

A mixer with a new concept design has been adapted into water treatment plants. It reportedly cuts down the energy consumption of the mixer by the new mixer, which moves vertically and creates internal flows toward its bottom. However, no experimental observations have been made on the internal flow caused by a vertical impeller. In this study, a radiotracer experiment, radioactive particle tracking (RPT) technique, and particle image velocimetry (PIV) were carried out to visualize the flow in the mixer, and compared to each other. The results show that the flow patterns from these techniques are very similar to each other, and the performance of the mixer was good enough to mix the inner materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.840-845
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• 2013

In this paper, the broadband frequency double down-converter based on LC filter technologies has been designed and implemented, and its performances are introduced. The Designed frequency double down-converter is consisted with a low-noise amplifier, mixer, IF amplifier, LC filter, DC-block capacitor and RF-bypass capacitor. Especially, instead of active devices of a typical converter, the suggested converter designed using passive devices to provide both low-power consumption and low-cost model. As results of the measurement, the implemented frequency double down-converter realizes the broadband performance with the bandwidth of 100MHz (13~113MHz) at the center frequency of 63MHz, and its gain is approximately 40dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.608-618
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• 2004

In this paper, modifying the diode star double balanced mixer of Maas, a novel resistive 60 GHz pHEMT MMIC star mixer is suggested. Due to star configuration, troublesome IF balun for ring configuration FET mixer is not necessary. In addition, the sysematic design method of dual balun through EM simulation is suggested rather than the design by inspection as Maas. The mixer circuit is fabricated as MMIC on CPW base using 0.1 um GaAs pHEMT Library of MINT in Dongguk University. The size is 1.5 ${\times}$ 1.5 $\textrm{mm}^2$ and its performance is adjustable by DC supply. It can be operated as both up and down converters and it shows the conversion loss of about 13∼18 ㏈ over the full V-band frequencies.