• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.443-447
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• 2003

In this work. using 0.2 GaAs modulation doped FET(MODFET), a high performance DBS downconverter MMIC was developed for direct broadcasting satellite (DBS) application. Without LNA, the downconverter MMIC showed a very low noise of 4.8 dB, which is lower by 3 dB than conventional ones. A low LO power of -10 dBm was required for the normal DBS operation of the downconverter MMIC. which reduced the power consumption via a removal of LO amplifier on MMIC. It required only a low power consumption of 175 mW, which is lower than 70 percent of conventional ones. The LO leakage power at IF output was suppressed to a lower level than 30 dBm, which removes a bulky LO rejection filter on a board. The fabricated chip, which include a mixer, If amplifiers. LO rejection filter, and active balun, exhibited a small size of $0.84{\times}0.9\textrm{mm}^2$.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.99-104
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• 2013

In this paper, we developed a fully integrated downconverter MMIC (monolithic microwave integrated circuit) including Lange coupler and output active balun for millimeter wave applications. Concretely, ${\lambda}$/4 transmission line was added to Lange coupler for size reduction of RF/LO input, and mixed RF/LO signals were applied to gate of the FET of mixer. Active balun was used at output port for a coupling of out-of-phase IF output signals. According to measured results, the proposed downconverter MMIC showed good RF performances. For example, the downconverter MMIC showed an LO leakage power of -25 dBc at IF output port, and a RF-LO isolation of 18 dB. Therefore, off-chip components such as LO rejection filters were not required for a normal operation of the proposed downconverter MMIC. The proposed downconverter MMIC showed a conversion gain of 10.3 dB at RF frequency of 63 GHz. The size of the downconverter MMIC including all active and passive components was $2.2{\times}1.4mm^2$.

• Electrical & Electronic Materials
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• v.23 no.11
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• pp.16-27
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• 2010

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.777-783
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• 2007

In this work, a highly integrated downconverter MMIC employing HBT(heterojunction bipolar transistor) was developed for application to one chip tranceiver solution of Ku-band commercial wireless communication system. The downconverter MMIC (monolithic microwave integrated circuit) includes mixer filter. amplifier and input/output matching circuit. Especially, spiral inductor structures employing SiN film were used for a suppression of LO and its second harmonic leakage signals. Concretely, they were properly designed so that the self-resonance frequency was accurately tuned to LO and its second harmonic frequency, and they were integrated on the downconverter MMIC.