• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.482-485
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• 2007

The S-Band SSPA is front-end equipment to transmit both LRIT and HRIT to COMS. To provide the required EIRP, S-Band SSPA is designed to generate maximum 1kW power at its 1dB gain compression point (P1dB). Due to the operation for 24 hours per seven days, the verification on the performance of S-Band SSPA was performed thoroughly. This paper presents that major requirements such as maximum 1kW power, maximum -26dBc of IMD characteristic at 500W output and around -57dBc of coupling factor were verified through proposed test configuration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.910-916
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• 1999

This paper presents the effective improvement of the thermal runaway phenomenon in high power SSPA when the RF input signal is not provided. The total gate resistors are optimized by the experiments and deducing the variation of velocity and currents of thermal runaway, which is based on manufacturer's recommendation. Especially, it is solved the complex thermal runaway that related gate resistors with the gate voltage variable circuit. The result of this paper is able to apply for improving the thermal runaway in existence of high power SSPA for WLL, cellular system and PCS repeater.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.69.6-69
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• 2001

The SSPA makes the power level of EIRP up to 16W, and compensates for temperature to the SSPA´s maximum stability. The up and the down converters are dually conversed like as individual synthesizers for selecting of independent transmit-receive transponder. The function of the up-converter is to convert the 70MHz IF signal modulated in the indoor unit modem into a 14.0 ∼ 14.5 GHz Ku-band up-link signal to be sent to the antenna. The down-converter converts the 12.25 ∼ 12.75 GHz Ku-band down-link signal or a trouble malfunction of SSPA may be a fatal factor to operation of the whole satellite communication network. Therefore, this study developed the remote monitoring and control program to monitor the SSPA´s status before the problem occurs for stable operation of the system. This software ...

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1079-1086
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• 2012

In this paper, X-band 60 W Solid-State Power Amplifier with sequential control circuit and pulse width variation circuit for improve bias of SSPA module was designed. The sequential control circuit operate in regular sequence drain bias switching of GaAs FET. The distortion and efficiency of output signals due to SSPA nonlinear degradation is increased by making operate in regular sequence the drain bias wider than that of RF input signals pulse width if only input signal using pulsed width variation. The GaAs FETs are used for the 60 W SSPA module which is consists of 3-stage modules, pre-amplifier stage, driver-amplifier stage and main-power amplifier stage. The main power amplifier stage is implemented with the power combiner, as a balanced amplifier structure, to obtain the power greater than 60 W. The designed SSPA modules has 50 dB gain, pulse period 1 msec, pulse width 100 us, 10 % duty cycle and 60 watts output power in the frequency range of 9.2~9.6 GHz and it can be applied to solid-state pulse compression radar using pulse SSPA.

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.323-327
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• 2004

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.319-325
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• 2004

FHMA(frequency hopping multiple access) communication system has good performance for the LPI and AJ(low probability of intercept and anti-jamming) application. However, high PAPR(peak to average power ratio) happens in the base-station or the repeater system because of a large number of users. In general, predistorter is used to complete the HPA(high power amplifier) nonlinear characteristics. This paper analyzes BER performance when magnitude of IBO(input back oft) and the number of user are considered as the system parameters. In case of the SSPA(solid state power amplifier), the predistorter does not always work as a complete nonlinear compensator. We find that there is a minimum value of IBO for the predistorter to compensate for the nonlinear SSP A, which is changed as the number of user. If IBO is lower than 6 ㏈ at the user number of 16 and p=1, the system with predistorter is poorer than the one without predistorter. Only when the IBO is over 6 ㏈, predistorter does work as a nonlinear compensator. We call it as cross-over IBO value. TWTA improves the more compensation performance than SSPA because characteristic AM/AM of TWTA has more nonlinear than SSPA. At the BER=10$\^$-3/, there are SNR power gains of about 2.5 ㏈ and 3 ㏈ due to the predistorter when the numbers of users are 16 and 32, respectively.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.27-31
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• 1996

In this paper, The SSPA(Solid State Power Amplifier) is 100 watts amplifier which is used with C-Band Satellite communication Up-Link frequency, 5.875 ∼6.425 GHz. SSPA requires more output power than is available from a single GaAs FET with result it is necessary to combine the output of many device. To achieve a high power, it is important to make a good N-way power divider which has a small different phase, good combining efficiency and high power handling capability. The reliability of Power GaAs FET decrease with increasing junction temperature, power amplifier in general dissipate amount of power. It is important to provide them with a heatsink and a temperature compensation circuit to dispose of the unwanted heat. To compensate temperature, Using PIN diode attenuator, it is enable to get a precision gain control. The output power of the SSPA is more than 100 watt with which the TWTA (Traveling-Wave Tube Amplifier) can be replaced. Each stage was measured by the Network analyzer PH8510C, Power meter Booton 42BD, The gain is more than 53 dB, flatness is less than 1.5 dB.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.425-432
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• 2014

Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.853-862
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• 2019

In this paper, we designed a 4.5kW X-band SSPA transmitter to replace the TWTA search radar transmitter with low MTBF and high maintenance cost. The transmitter is designed for the performance of over 520W average transmission output and 4.0kW maximum transmission output. In particular, by implementing a graceful degradation, it is designed to maintain better performance than conventional TWTA transmitter up to 40% (13 assembly modules) failure level of 200W power amplifier assembly. Through an experiment on the effective range of X-band, the performance of proposed transmitter verified the values of the maximum transmission output 6.1kW, spurious output 69.16dBc, RF pulse rising time 15.2ns and RF pulse falling time 16.3ns. The experiment confirmed the change of output power according to the graceful degradation due to fault injection.