Research on Millimeter-wave Reflection-type Modulators and Their Applications

• Main Authors: Hong-Yeh Chang, 張鴻埜
• Other Authors: Huei Wang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/09181829744241013141

博士 === 國立臺灣大學 === 電信工程學研究所 === 92 === Reflection-type modulators and their linearization applications are presented in this dissertation. The research focuses on the development of millimeter-wave modulators using commercial GaAs HBT and HEMT MMIC processes. The analysis and design equations of imbalance effects for the reflection-type modulators are investigated to obtain the circuit design procedures, and the analysis results are also verified with the experimental results. The cold-mode models for HBT and HEMT devices are developed in this dissertation for the circuit design and simulation. Broadband reflection-type BPSK and IQ modulators for the digital modulation applications were developed between 30 and 140 GHz. These MMICs demonstrated well LO suppression and modulation quality with the LO power of lower than -8 dBm. A vector signal characterization for the measurement of the millimeter-wave modulators is presented. Moreover, the equations of carrier and sideband suppressions for the reflection-type IQ modulator are investigated by using a power series for the cold-mode devices. The characterizations of the modulator MMICs were performed and compared with the spectrum characterizations. The phenomenon of via-hole resonance above 100 GHz for the BPSK modulator is also observed. After laser-repairing, the operation frequency of the BPSK modulator MMIC has been further extended to 140 GHz. A W-band direct-conversion transmitter for digital modulation applications was developed. The AM-AM and AM-PM distortions in a quadrature-modulator transmitter were also investigated. From the analysis, a new scheme of linearization is developed for W-band transmitter applications. By using the digital pre-distortion technique, this transmitter demonstrated an output channel power of 19-dBm around 77 GHz. �nFor�n�����{QAM�z�nQPSK�nand�n��/4-DQPSK modulation schemes, the adjacent channel power ratios and the error vector magnitudes were all improved by great than 10 dB and 25%, respectively.