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Wang F.,Suzhou University | Hu S.,Nanjing Southeast University | Zhang X.,Suzhou SIP Education Development and Investment Co. | Gao H.,Nanjing Southeast University
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2011

This paper presents the pre-matching and matching approach to RF LDMOS device for designing of high-power RF amplifier. A pre-matching circuit in flange and an input/output matching circuit on PCB have been developed for one RF LDMOSFET, so that it can be matched to the systemic reference impedance of 50Ω within a given frequency range. The simulation and measured results show that this RF LDMOS amplifier exhibits a P-1dB of 48.8 dBm at 950 MHz. Its DC to RF efficiency is up to 66.4%. Power gain is around 17.8 dB. And IM3 is below -30 dBc, while the S11 is less than -10 dB across the frequency range of 869~960 MHz. Source


Hu S.,Nanjing Southeast University | Qian H.,Suzhou University | Sun X.,Nanjing Southeast University | Zhang X.,Suzhou SIP Education Development and Investment Co. | Gao H.,Nanjing Southeast University
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2011

A novel ballast resistor network of power cells is proposed, and the theory of the tree-like structure with strong coupling effect is analysed. The simulation results based on COMSOL MULTIPHYSICS show that: this adaptive ballast resistor network can adjust the current flowing through HBT arrays by coupling, resulting in a more uniform temperature distribution. Two power amplifiers of the same die area with different ballast resistor networks are designed and fabricated. Temperature of these two power amplifiers is measured at the same bias condition and, by comparison, the power cells with the novel ballast resistor network can achieve a more uniform temperature distribution than that with the conventional one and thus solve the problem of thermal runaway. Source


Liang C.,Suzhou University | Liang C.,Nanjing Southeast University | Hua Y.,Suzhou University | Hua Y.,Nanjing Southeast University | And 5 more authors.
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2011

A CDMA power amplifier with a power detector and an adaptive linear circuit is designed. The power detector is used to adjust the bias point according to the input signal amplitude, which increases the efficiency when the output power is low and further more increases the system total efficiency. The adaptive linear circuit can efficiently improve the linearity by suppressing gain compression and phase distortion of the power amplifier. Measurement results of this novel amplifier fabricated based on 2 μm InGaP/GaAs HBT technology show that: the collector current is considerably reduced when the output power is less than 10 dBm and the system total efficiency reaches up to 2.2 times compared with the conventional amplifiers. The 1 dB compression point rises up from 30 dBm to 32 dBm. The ACPR, ALTR and IM3 are improved by 5 dB, 12 dB and 11 dB respectively when the output power is 28 dBm. Source


Sun X.,Nanjing Southeast University | Sun X.,Suzhou SIP Education Development and Investment Co. | Dai W.,Infineon Technologies | Yan W.,Soochow University of China | And 3 more authors.
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2010

This paper presents the model development of Agere eletro-thermal transistor, an electro-thermal large signal nonlinear RF-LDMOSFET model used in radio frequency (RF) power amplifiers (PAs). We first describe our model schematics, then the iso-thermal and pulsed device characterization systems used in the parametrization of the model are described. The extracted model is implemented in Agilent's Advanced Design System (ADS) for the development of several PAs. Finally, the model accuracy is measured by comparing several experimental verifications of physical chips against those of EDA designs. Source

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