Millimeter-wave Transmitter Linearization and Gigabit Wireless Communication Systems
Date Issued
2007
Date
2007
Author(s)
Tsai, Jeng-Han
DOI
en-US
Abstract
The purpose of this dissertation is to develop millimeter-wave transmitter linearization and wireless Gigabit communication systems.
As the demands for wireless communication technology are growing rapidly recently, the microwave frequency bands have been saturated with various communication applications. For high-capacity and high-speed wireless data transmission, the communication channel needs larger bandwidth. Therefore millimeter-wave frequency bands are the solution for high data rate communication system, even wireless Gigabit applications. To enhance the spectral efficiency, modern wireless communication systems tend to use complex digital modulation schemes. These communication systems require a high-linearity MMW transmitter to minimize the spectral re-growth and maintain modulation accuracy. However linear output power of the power amplifier is an expensive resource. Therefore, in this dissertation we proposed a low-loss built-in linearizer using a shunt cold-mode HEMT. The linearizer has advantages of low insertion loss, compact die-size, and zero dc consumption and suitable for MMW linearization applications. To demonstrate the function of the linearizer, MMW power amplifier with built-in linearizaer for pre-distortion linearization has been presented. After linearization, the linearity of the power amplifier has been improved and the spectrum re-growth can be suppressed by 8 dB. For the same linearity requirements, the linear output power of the MMW power amplifier has been doubled. To the best of our knowledge, this is the first MMW power amplifier with a low-loss built-in linearizer. In addition, a MMW 40-48 GHz broadband sub-harmonic transmitter has been presented. The transmitter consists of a sub-harmonic mixer, a band-pass driver amplifier, and a built-in linearizer. The linearizer with post-distortion characteristic can enhance the linearity of the whole transmitter. Furthermore, a MMW Doherty amplifier with post-distortion linearization is presented. The topology of the Doherty amplifier is similar to a post-distortion system. Therefore we can improve the linearity and efficiency of the amplifier simultaneously without increasing the chip area.
Follow are the introduction of the MMW Gigabit wireless communication systems. For MMW system demonstration, the MMW MMIC chips were assembled to transmitter and receiver modules. The experimental results show the transmitter and receiver modules have been applied to MMW point-to-point communication system successfully. However, for MMW marketplace requirement, not only fabricating a chipset with high performance but also size and cost reductions in the transceiver are important issue. Therefore sub-harmonic modulator and demodulator are designed and fabricated using standard CMOS process for MMW direct-conversion transceiver in this dissertation. The main problem, LO leakage, can be improved by using sub-harmonically pumped mixing technique. A MMW four-way quadrature divider using 90° coupler and 180° balun have been implemented in the CMOS process to provide equal amplitude and quadrature-phases LO signals for sub-harmonically pumped modulator and demodulator. For broadband sub-harmonic modulator and demodulator designs, the low quality factor impedance matching network is design and analysis. Finally the experimental results show the sub-harmonic modulator and demodulator MMIC feature Gigabit modulation and demodulation quality for MMW wireless Gigabit direct-conversion applications.
Subjects
線性化
毫米波
功率放大器
發射器
十億位元
Linearization
Millimeter-wave
Power amplifier
Transmitter
Gigabit
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-96-F91942044-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):3ee09a98fc2ccc77060a42ecf1c72671