Measurement Results for the Dynamic Supply CMOS RF Power Amplifie - Linear CMOS RF Power Amplifiers for Wireless Applications - page 49

Table 4.3 Summary of
measured S parameters at
matched conditions

SP 2.4 GHz 5.2 GHz

S 11 (dB) − 12 . 6 − 16 . 2

S 21 (dB) 8 . 4 4 . 6

S 22 (dB) − 12 . 2 − 15 . 9

S 12 (dB) − 19 . 9 − 16

Fig. 4.13 Measured CW power gain at 5.2 GHz

4.4.2 Single-Tone Measurements

Single-tone, or Constant Wave (CW), measurements can be used to assess the lin-
earity of a PA in terms of its 1 dB compression point. We have preferred, however,
to use 2-tone tests and be able to assess quantitatively the nonlinearity level at each
output power level through the measurement of the IMD3. The 2-tone measure-
ment results showing the efficiency and linearity behavior of the power amplifier
are treated in the next section where we compare the results for a constant 2.5 V
supply operation with those for the dynamic supply operation. We present, never-
theless, in Fig. 4.13 , the single-tone power gain of the PA at 5.2 GHz for different
fixed supply voltages. This is done so that a comparison among the S-parameter,
single-tone, and 2-tone power gains can made in Sect. 4.5.1 on p. 50 .