| Presentation | 2007-03-09 Circuit Design of Highly Linear and Efficient Power Amplifiers for WCDMA Applications : Dynamic Predistortion and Polar Modulation Technologies Kazuaki KUNIHIRO, Shingo YAMANOUCHI, Kiyohiko TAKAHASHI, Yuuichi AOKI, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | This paper presents linearization and efficiency-enhancement techniques, i.e., dynamic predistortion (PD) and polar modulation, for WCDMA handset power amplifiers (PAs). The dynamic-PD was designed to compress dynamic-gain of a driver-stage PA at base-band frequency; this compensates for expanded gain of an output-stage PA, resulting in flat dynamic-gain in total. It is shown that compressing dynamic-gain is equivalent to generating anti-phase inter-modulation-distortion (IMD3) which cancels out in-phase IMD3 of the output-stage PA, thus minimizing total IMD3. The fabricated two-stage InGaP/GaAs HBT PA with the dynamic PD exhibited an ACPR of -40 dBc and a PAE of 50% at an average output power of 26.8 dBm with an extremely low quiescent current of 20 mA. A polar-modulation PA using a new linear-assisted delta-modulation (LADM) envelope-amplifier is also described. The LADM system is composed of a highly efficient switching block based on a 200-MHz-clock delta-modulator, which is implemented in a 0.18-μm CMOS IC, and a highly accurate linear block. In the LADM approach, the residual quantization noise and distortion of switching amplification are removed through the assistant linear process; thus, a sufficiently low ACPR of -45 dBc and a small EVM of 1.7% can be achieved without a predistortion technique. The developed polar transmitter nearly doubles the average efficiency in the 10- to 15-dB back-off region of class-AB PAs. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Power amplifier / code division multiple access (CDMA) / predistortion / polar modulation / delta modulation |
| Paper # | MW2006-193 |
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| Committee | MW |
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| Conference Date | 2007/3/2(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Registration To | Microwaves (MW) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Circuit Design of Highly Linear and Efficient Power Amplifiers for WCDMA Applications : Dynamic Predistortion and Polar Modulation Technologies |
| Sub Title (in English) | |
| Keyword(1) | Power amplifier |
| Keyword(2) | code division multiple access (CDMA) |
| Keyword(3) | predistortion |
| Keyword(4) | polar modulation |
| Keyword(5) | delta modulation |
| 1st Author's Name | Kazuaki KUNIHIRO |
| 1st Author's Affiliation | System Devices Research. Laboratories, NEC Corporation() |
| 2nd Author's Name | Shingo YAMANOUCHI |
| 2nd Author's Affiliation | System Devices Research. Laboratories, NEC Corporation |
| 3rd Author's Name | Kiyohiko TAKAHASHI |
| 3rd Author's Affiliation | System Devices Research. Laboratories, NEC Corporation |
| 4th Author's Name | Yuuichi AOKI |
| 4th Author's Affiliation | System Devices Research. Laboratories, NEC Corporation |
| Date | 2007-03-09 |
| Paper # | MW2006-193 |
| Volume (vol) | vol.106 |
| Number (no) | 560 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |