A novel class-E power amplifier with an asymmetrical spurline filter and its linearization

The third-order intermodulation coefficient (IMD3) is an important measure of linearity of a PA, and it is always measured using a two-tone excitation signal. A two-tone excitation signal with equal amplitudes and a frequency spacing of 10 MHz is adopted in this simulation. For comparison, both the measurement results of the proposed PA without EER linearization technology at a constant drain bias of 35 V with two test signals at 995 MHz and 1005 MHz and the proposed PA with EER linearization technology are given. According to the Fig. 3(a), compared to the PA without EER, the output power of the PA with EER declines less than 1 dBm on average. However, the IMD3 is improved significantly by using EER linearization technology. Fig. 3(b) shows the IMD3 characteristics versus output power. It is showed that the IMD3 of the class-E PA with EER is improved by 12 dB on average than the IMD3 of the PA without EER, and the best improvement of 14.9 dB is achieved at the output power of 38 dBm. As showed in Fig. 3 (c), the IMD3 of the class-E PA has improvement of 17.4 dBm at the input power of 21 dBm, compared to the class-E PA without EER. Fig. 3 (d) shows that the class-E PA with EER has a much lower IMD3 than the PA without EER at the same level of gain. The results demonstrate that by using the EER linearization technology, the linearity of the class-E PA with an ASF is improved obviously.