• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.6
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• pp.538-545
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• 2002

In the orthogonal frequency division multiplexing (OFDM) system, the nonlinear distortion in the high power amplifier(HPA) degrades the system performance because of the high peak-to-average power ratio (PAPR). In this paper, a semi-analytical method is newly proposed for the performance evaluation of the nonlinearly distorted OFDM communication system. In the proposed method, at first, the probability density function (pdf) of the PAPR is generated by computer simulation. Then, mean and variance of the non-linear distortion noise process are computed. Next, the overall BER is found by the analytical method. When the equivalent SSPA model is applied in case of the QPSK/16-QAM and AWGN channel, the BER is calculated for the variation of the IBO(input back-off) and PAPR parameter. It is shown that the results by proposed method are very similar to those of the conventional Monte-Carlo method. The computation time can be considerably reduced than the conventional method that depends on the magnitudes of BER and IBO.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.168-171
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• 2010

본 논문에서는 GaN HEMT 소자를 이용한 고출력 고효율 특성을 가지는 광대역 SSPA의 개발을 다루고 있다. 개발한 SSPA는 8W 급과 15W 급의 GaN HEMT 소자를 사용하여 Pre-Drive 증폭단을 구성하였으며, Drive 증폭단은 50W/150W급 GaN HEMT 소자를 직/병렬구조로 사용하였다. Main 증폭단은 4-way 분배기와 결합기를 이용한 Balanced Structure를 적용하여 높은 출력을 구현하였으며, 안정적인 동작을 위하여 음(-)전원 제어 회로와 출력신호 검출 회로를 포함하고 있다. 제작된 SSPA의 사용가능 대역은 2.9GHz~3.3GHz로 단일전원을 사용하고 있으며 100us 펄스 폭, 10% Duty Cycle 조건에서 60dB의 전압이득, 1kW 출력과 약 28% 효율 특성을 가지는 것으로 측정되었다. 본 논문에서 개발한 SSPA는 S-대역을 사용하는 레이더시스템의 송신단에 적용될 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1239-1247
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• 2012

In this paper, design and fabrication of solid state power amplifier(SSPA) using GaN HEMT chip for X-band frequency are presented. The SSPA consists of the power supply for stable power and the control unit for communication and controlling the internal module, the RF Part to amplify RF signal, In particular the adopted active device for the RF Parts is GaN HEMT Bare chip of TriQuint company, the RF parts consists of pre-stage, drive-stage, main power-stage and each amplifier is designed with input and out matching circuit. The developed power amplifier demonstrated more than 300 W peak output power in condition of 26 % duty, max. pulse width 100us for the X-band frequency( 500 MHz bandwidth) and can apply to marine radar systems.

• Electronics and Telecommunications Trends
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• v.29 no.6
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• pp.1-13
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• 2014

GaN(Gallium Nitride)는 3.4eV의 넓은 에너지 갭으로 인하여 고전압에서 동작이 가능하고, 분극전하를 이용한 캐리어 농도가 높아 높은 전류밀도와 전력밀도를 얻을 수 있으며, 높은 전자 이동도와 포화 속도로부터 고속 동작이 가능하여 고주파 고출력 고효율 소형의 전력증폭기 소자의 재료로 적합하다. 본고에서는 민수 및 군수 겸용 Ku-대역 및 Ka-대역 GaN 고출력 전력증폭기(SSPA: Solid-State Power Amplifier)와 관련된 GaN 전력증폭 소자, GaN 전력증폭기 MMIC(Microwave Monolithic Integrated Circuit), 내부정합 패키지형 GaN 전력증폭기 및 GaN SSPA에 대하여, 국내외 특허 기술동향과 연구개발 기술동향을 중심으로 고찰하고자 한다. 국외의 GaN 고주파 고출력 전력증폭기 기술의 연구동향이나 특허동향을 심층분석하여 연구개발에 활용하고자 한다.

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.93-96
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• 2004

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.35-42
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• 2021

The research of amplifier have been actively conducted to replace the Traveling Wave Tube Amplifier (TWTA) in the mmWave. For Solid State Power Amplifiers (SSPA), which combine semiconductor-type devices to obtain high output, Low-loss, high-efficiency combination techniques are required to meet the required output as the output of a single relatively low device is relatively low. In this paper, we design and produce an 8-way waveguide combiner and a reflective loss of more than 20dB and a binding efficiency of 85% or more were identified. Field analysis calculates the critical power inside the combiner. It secured stable Power Ratings and built-in coupler for power monitoring to achieve miniaturization and light weight.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.22-27
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• 2002

The 25 Watt hybrid MIC SSPA has been developed in the frequency rang from 1.6265 GHz to 1.6465 GHz for uplink of INMARST's earth station. To simplify the fabrication process, the whole system is designed of two parts composed of a friving amplifier and a power amplifier. The Motorolas MRF-6401 is used for driving part, the Motorolas MRF-16006 and MRF-16030 is used the power amplifier. We reduced weight and volume of high power amplifier through arranging the bias circuits in the same housing. The realized SSPA has more than 30 dB for gain within 20 MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output port are less than 1.7, respectively. The output power of 44 dBm is achieved at the 1 dB gain compression point of 106365 GHz These results reveal a high power amplifier of 25 Watt which is the design target. The Proposed SSPA manufacture techniques in this paper can be applied to the implementation of high power amplifiers for some radars and SCPC.

• 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.65-72
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• 2003

In this work a 6-stage hybrid power amplifier which can be used for the wireless communication systems for MMC(hficrowave Micro Cell) and ITS wireless communication system is designed and fabricated. Ihe power amplifier's each stages was fabricated Hetero-junction Power FET of bare chip type and an alumina substrate with $\varepsilon_{r}$=9.9 and 15-mil thickness. The measured results of power amplifier module showed 33.2$\~$36.5 dB small signal gain, 33.0$\~$34.0 dBm output power at forward frequency (17.6 GHa $\~$ 17.9 CHz) and 36.0$\~$37.0 dB small signal gain, 33.0$\~$34.5 dBm output power at reverse frequency (19.0 GHz $\~$19.2GHz).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.2
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• pp.281-290
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• 1999

This paper presents the development of a high power amplifier for a transmitter of INMARSAT-C operating at L-band(1626.5∼1646.5 MHz). To simplify the fabrication process, the whole system is designed of two parts composed of a driving amplifier and a high power amplifier The HP's AT-41486 is used for driving part and the SGS-THOMSON microelectronics' STM1645 is used the high power amplifier. The SSPA(Solid State Power Amplifier) was fabricated by the both circuits of RF and temperature compensation in aluminum housing. The realized SSPA has more than 36 dB for small signal within 20MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output Port are less than 1.5:1, respectively. The output Power of 42.2 dBm is achieved at the 1636.5 MHz. These results reveal a high power amplifier of 20 Watt which is the design target.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2228-2237
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• 1994

This paper describes the development of a Ku-band ($12.25GHz\sim12.75GHz$) SSPA intended as a replacement for TWTAs used in communication satelite transponder. The power stage of the amplifier consists of tow intrmally matched 8W FET divices combined using the branch-line coupler. To operate this stage, the drive stage has been designed with intermally matched 2W, 4W, 8W FET and two medium power FETs. The entire amplifier is made up by a aluminum chassis housing both the RF circuit and the bias circuitry. A regrlator/sequencing circuitry is used for FET biasing. The amplifier results implemented in this way show $41\pm0.3dB$ small-signal gain, 15W saturation power, a typical two tone $IM_3=-21.5dBc$ with single carrier backed off 5dB from saturation, $2^*/dBmax$ AM/PM conversion, and $3.47\pm0.25nsec$ group delay.