Linearity Improved Doherty Power Amplifier Using Composite Right/Left-Handed Transmission Lines

Design of Linearity Improved Asymmetrical Gan Doherty Power Amplifier Using Composite Right/Left-Handed Transmission Lines

“…The calculated EVMs of 100 MHz LTE-Advanced signal at 37 dBm are shown in Table 4, the EVMs of the DPA using CRLH-TL are better than the Traditional DPA with or without DPD. Table 5 shows the performance of the proposed DPAs compared to other works [16,[25][26][27]. In addition, the design's strengths of the proposed DPAs as compared to existing techniques listed in Table 5 have also been described.…”

“…In addition, the design's strengths of the proposed DPAs as compared to existing techniques listed in Table 5 have also been described. First, compared with the other amplifiers in Table 5, the proposed two DPAs have 100 MHz bandwidth, which is able to operate in wider frequency bands, the operation frequency is also higher, which is more appropriate for LTE-Advanced applications Second, the input and output matching networks of the proposed two DPAs completely consist of simplified and optimized series transmission lines, compared with the lumped component matching networks used in [25,26] and the parallel transmission line matching networks used in [16,27], the simplified series transmission lines matching networks result in a reduction of the complication of the schematic structure and tuning. Last, the linearity is improved by suppressing second harmonic in [16] and this work (CRLH-TL), the max P out of [16] is 15 dB smaller than that of this work (CRLH-TL), but this work (CRLH-TL) still maintaining a comparable IMD3.…”

“…First, compared with the other amplifiers in Table 5, the proposed two DPAs have 100 MHz bandwidth, which is able to operate in wider frequency bands, the operation frequency is also higher, which is more appropriate for LTE-Advanced applications Second, the input and output matching networks of the proposed two DPAs completely consist of simplified and optimized series transmission lines, compared with the lumped component matching networks used in [25,26] and the parallel transmission line matching networks used in [16,27], the simplified series transmission lines matching networks result in a reduction of the complication of the schematic structure and tuning. Last, the linearity is improved by suppressing second harmonic in [16] and this work (CRLH-TL), the max P out of [16] is 15 dB smaller than that of this work (CRLH-TL), but this work (CRLH-TL) still maintaining a comparable IMD3. In [25,26], although the test signals are 20 MHz and 10 MHz, which are smaller than the bandwidth of this work (CRLH-TL), the ACPRs are still no more than that of this work (CRLH-TL); The IMD3 of this work (CRLH-TL) is approximate −40 dBc at 38 dBm, same as the IMD3 of [27], but the proposed DPA of this work (CRLH-TL) is able to operate in a higher power level, and the linearity also improved significantly after DPD.…”

“…The phase of CRLH-TL and RH-TL are identically −π/2 at the fundamental frequency f 1 , nevertheless, at the second harmonic frequency 2f 1 , the phase of CRLH-TL and RH-TL are approximately −2π and −π, respectively, consequently, the phase difference is approximately π. Therefore, it is possible to suppress the second harmonic of DPA by using CRLH-TL, resulting in a linearity improvement of the DPA [16].…”

“…On the other hand, in order to improve the linearity of Doherty power amplifier, one of the possible and simplified techniques is Composite Right/Left-Handed Transmission Lines (CRLH-TL) for its character of suppressing the second harmonic of the carrier amplifier of the Doherty power amplifier. Linearity can be improved by replacing the traditional λ/4 transmission line with CRLH-TL [16,17].…”