Spectrum modeling for linear RF power amplifier design for digital cellular communication signals

摘要

One of the critical and costly components in digital cellular communication systems is the RF power amplifier. Theoretically, one of the main concerns in an RF power amplifier design is the nonlinear effect of the amplifier. The nonlinearity control is specified by the out-of-band power emission levels. The nonlinearity of an RF amplifier is described by the third-order intercept point (IP3). Quantitatively, no clear relationship or expression currently exists between the out-of-band emission level and the nonlinearity description related to IP 3. The lack of such a relation poses difficulties for RF designers choosing components. Further, in experiments and analysis, it was discovered that, in some situations, using IP3 only is not enough to describe the spectrum regrowth, especially when the fifth-order intercept point (IP5) is relatively high compared to the third-order intermodulation.;In this dissertation, we will analyze the nonlinear effect of an RF power amplifier on several digital cellular communication systems, such as CDMA (IS-95 Standard), TDMA (IS-54 and IS-136 Standards), GSM Standard, and M-16QAM (MIRS Standard). We will then derive the expressions of the estimated out-of-band emission levels for CDMA and TDMA signals in terms of the power transistor's intermodulation coefficients IP3 and IP5, as well as the power level and bandwidth of the signal. We will also provide insight for RF power amplifier design for GSM and M-16QAM.;These results will be very useful to system and component engineers in the design and test of RF power amplifiers.