| With the rapidly developing field of mobile communications, the communications system overall trend is toward high-efficiency, multi-band, ultra-wideband direction. Undoubtedly, linearity and effectiveness of the work has become for the power amplifier performance required for performance of the play two of the most important design trends. Power amplifier modules as its entire share in the overall system transmitter affected consumption, gain as demand increases gradually occupy the most important position in the mobile communications transmitter module. As the largest power transmitter modules, RF power amplifier inefficiency causes an increase in the cost of processing the copper block, increasing system power consumption, and reduced stability of the circuit. The loss of part of the efficiency of the amplifier adopted as a conventional power amplifier design approach commonly used in exchange for linearity to meet, in this one, Doherty technology is currently being applied across most, to meet linearity specifications excellent efficiency under a revolutionary the technical trend.Technical indicators for the specific meaning, and indicators on the power amplifier often mentioned in conjunction represented in this paper Doherty power amplifier (Doherty Power Amplifier, referred DP A) work of theoretical analysis and different working conditions, we have made detailed description taken in conjunction simulation results on the performance of specific indicators to make comparison. According to the experimental project needs to design requirements, after a lot of optional, finally adopted Freescale model MRF8S26120H transistors as the main amplifier components. An essential part of the design of the amplifier, such as the DC simulation, stability analysis, design input and output matching circuit design as well as compensating lines are described in detail. Improved by performing input power splitter design, implementation of a work in 2550MHz-2650MHz band broadband DP A, through the comparison with the traditional DPA radically improved Doherty technology narrowband defects, and its processing testing and validation.Enhanced DPA DPA with traditional simulation performance comparison shows that the power amplifier is designed to work in the band gain of 16dB and the gain flatness within 1.6 dB, remains a power added efficiency of up to 55.6%, 1dB compressed output power greater than 50dBm. In the case of the overall performance with the traditional flat DPA, DPA enhanced through improved input power splitter designed to make up for deficiencies Doherty technology narrow bandwidth, upgrade the operating bandwidth from 20MHz to 100MHz. Enhanced DPA and wherein a single tube class AB amplifier performance comparisons for efficiency and linearity has improved significantly, just gain flatness slightly worse. In the 1dB compression point of 45dBm input power within a good linearity. Because of the impedance matching and bias network design refinement in the design process and the use of improved power splitter increases the bandwidth of the amplifier, relative to the average of the Doherty amplifier, the power amplifier of the indicators have improved to some extent, this is also one of this article Great innovation. |
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