Drain-voltage dependency of memory effects in W-CDMA base station digital predistortion linearizers with compound semiconductor power amplifiers
✍ Scribed by Takeshi Takano; Yasuyuki Oishi; Toru Maniwa; Hiroyuki Hayashi; Toshihide Kikkawa; Kiyomichi Araki
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 470 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0895-2477
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✦ Synopsis
With regard to wideband predistortion type power amplifiers, such as shared amplifiers used in W-CDMA base stations, the memory effects associated with RF power amplifiers degrade power efficiency. Aiming to solve this problem, we find that a high-voltage compound semiconductor device has sufficient ACLR performance to mitigate these memory effects. We tested two kinds of compoundsemiconductor devices, namely, a GaAs FET and a GaN HEMT. The GaAs FET, with an operating voltage (V op ) of 12 V, a saturation output of 240 W, and a push-pull configuration, was used as a low-voltage device. The GaN HEMT, with V op of 50 V, a saturation output of 200 W, and a push-pull configuration as well, was used as a high-voltage device. The test results for these devices in a predistortion linearizer configuration show that the high-voltage device (the GaN HEMT) achieved excellent characteristics in terms of distortion suppression and drain efficiency in four-carrier W-CDMA applications.