• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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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.

• Journal of Advanced Marine Engineering and Technology
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• 제37권1호
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• pp.105-113
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• 2013

본 논문에서는 ${\pi}$형 다중결합선로와 RCR 삽입구조를 이용하여 양호한 절연특성을 가짐과 동시에, 종래에 비해 상당히 축소된 형태의 초소형 윌킨슨 전력분배기를 GaAs MMIC상에 구현하였다. 본 논문에서 제안한 RCR 삽입설계법에 의해 윌킨슨 전력분배기의 선로길이가 ${\lambda}$/46까지 축소되어도 중심주파수에서 -23 [dB]의 절연특성이 유지되었으며, -8 [dB]의 절연특성을 가지는 종래의 ${\pi}$형 다중결합선로 윌킨슨 전력분배기에 비해 절연특성이 개선되었다. 본 논문에서 제안한 윌킨슨 전력분배기의 면적은 0.304 [$mm^2$]로서 GaAs상에 동일한 조건으로 제작된 종래의 윌킨슨 전력분배기 면적의 12.1%밖에 되지 않는다. 상기 윌킨슨 전력분배기는 C/X 밴드에서 양호한 RF 특성을 나타내었다.

• 한국군사과학기술학회지
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• 제12권4호
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• pp.446-451
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• 2009

In this paper, we described the design and test results of a high output power amplifier MMIC developed by using 0.5um power pHEMT processes on a 6-inch GaAs wafer for the X-band T/R module application. In the MMIC design, we have used a simple on-chip gate active bias technology to compensate the threshold-voltage variation of pHEMT during the fabrication process and 16-to-1 power combining method to achieve the output power over 10watt. The fabricated chip has an output power over 12watts and maximum PAE of 32% over the frequency range of fo +/-750MHz.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1248-1256
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• 2008

In this paper, basic characteristics of transmission line employing PPGM (periodically perforated ground metal) were investigated using theoretical and experimental analysis.According to the results, unlike the conventional PBG (photonic band gap) structures, the characteristic impedance of the transmission line employing PPGM structure showed a real value, which exhibited a very small dependency on frequency. The transmission line employing PPGM structure showed a loss (per quarter wave length) higher by $0.1{\sim}0.2\;dB$ than the conventional microstrip line. According to the investigation of the dependency of RF characteristic on ground condition, the RF characteristic of the transmission line employing PPGM structure was hardly affected by the ground condition in the frequency lower than Ku band, but fairly affected in the frequency higher than Ku band, which indicated that coplanar waveguide employing PPGM structure was optimal for RF characteristic and reduction of size. Considering above results, impedance transformer was developed using coplanar waveguide with PPGM structure for the first time, and good RF characteristics were observed from the impedance transformer. In case that {\lambda}/4$ impedance transformer with a center frequency of 9 GHz was fabricated for a impedance transformation from 20 to10 {\Omega}$, the line width and length were 20 and $500\;{\mu}m$, respectively, and its size was only 0.64 % of the impedance transformer fabricated with conventional microstrip lines. Above results indicate that the transmission line employing PPGM is a promising candidate for a development of matching and passive elements on MMIC.

• Journal of Advanced Marine Engineering and Technology
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• 제34권2호
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• pp.325-331
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• 2010

본 논문에서는 주기적 접지구조(PPGS)를 가지는 소형 단파장의 미앤더 선로를 GaAs MMIC(Monolithic Microwave Integrated Circuit) 상에 구현하였다. PPGS구조를 이용한 미앤더 선로는 기존의 미앤더 선로에 존재하던 용량 $C_a$와 함께 추가적인 용량 $C_b$를 가짐으로써 전체적인 용량이 커지게 되어, 단파장 특성을 보여주었다. 기존의 미앤더 선로는 주기적 구조가 아닌데 반해 PPGS 구조의 미앤더 선로는 주기적 구조이므로 $\beta$값이 큰 slow-wave가 존재하며, 이로 인해 종래의 미앤더 선로에 비해 선로 상에서 훨씬 더 큰 위상변화량을 보여준다. 본 논문에서는 상기 미앤더 선로의 특성을 실험적으로 고찰하여 PPGS 구조의 미앤더 선로를 병렬 인덕터로 사용할 경우, 기존 미앤더 선로를 사용할 때 보다 높은 인덕턴스 값을 가지므로 동일한 길이의 기존 선로보다 큰 인덕턴스 값을 가지는 정합 소자로써 사용할 수 있음을 확인하였다.