Microwave power amplifiers with digitally-controlled power supply voltage for high efficiency and high linearity

Improving the linearity‐efficiency trade‐off in FET power amplifiers using large‐signal IMD sweet spots

“…For this purpose, the optimum control path was modelled by a simple function: a 3 rd -order polynomial. The DSP unit can be the same as that used to generate the I and Q signals in the handset unit [4].…”

“…To compensate for the resultant AM-AM conversion, Saleh and Cox [1] suggested to predistort the input signal. This solution was adopted by Ranjan et al in [4]. These authors employed the same scheme as that proposed in [2], including a DSP unit to control digitally the drain DC-DC converter, and to carry out the digital predistortion of the amplifier-input signal.…”

Mobile Phone Power Amplifier Linearity and Efficiency Enhancement Using Digital Predistortion

“…Due to the smaller power stage usable in combination with the DP-concept considerably higher efficiencies can be obtained over typically used lower output power ranges. This is a very useful improvement for WCDMA systems, which have a big output power dynamic range [1]. For example in UMTS output powers from -50dBm to +27dBm are required, which depend on the position of the mobile station w.r.t.…”

Mobile phone power amplifier linearity and efficiency enhancement using digital predistortion

“…The predistorted signal has also a wider frequency band as can be seen in Fig.2b. The signal to the quantization noise power ratio of a sine wave in an ideal converter is [4], S/N= n×6.02+1.76 dB (1) where n can be defined as the effective number of bits and 1.76 dB offset is due to peak to RMS value of the sine wave. This offset changes with modulation type.…”

“…Therefore the DP is a promising linearization technique. It can also be easily implemented together with a DC-DC converter to achieve higher efficiencies [1].…”