Analysis And Implementation Of RF Active Bandpass Filters Using CMOS Technologies

RF filter is the one of the key components and the filter is integrated in the wireless systems. Furthermore, integrated continuous-time filter with low cost, low power, low insertion loss, high quality factor,and tuning center frequency is already the hot topic of RFIC. The researches into this dissertation are mainly about the design based on RF active CMOS filters, and demonstrate analyzing and implementing of CMOS RF active filters suited for wireless Multi-band applications.The main researches into the dissertation are the following:First of all, the high-linearity operational transconductance amplifier (OTA) is presented based on the MOS transistors in the triode-region. It is adopted the active degeneration-source resistors in order to reduce the third-order nonlinear distortion. Based on the structure of the OTA, a sixth-order chebyev bandpass filter is presented using passive LC ladder network synthesis through the transfer of the frequency and resistance. The simulated results show that the center frequency of the filter is adjustable about from 0.5MHz to 10MHz. The gain in the passband is about from -1.5dB to 19dB. When the center frequency is about 4MHz, the 3dB bandwidth is only 40 KHz, and the quality factor and the gain in the passband is adjustable by the controlled voltages.Secondly, the OTA of Nauta B is analized, and the transconductance of Nauta B closely correlates to the supply voltage. The adjustable bias voltage sources are used on the Nauta's OTA in order that the OTA can be operated at the adjusted gain, high linearity and high working frequency. Based on the proposed OTA, a CMOS ultra-high-frequency (UHF) biquadratic bandpass filter is presented using TSMC 0.25μm CMOS process. The center frequency of the filter is varied from 422MHz to 450MHz under the supply voltage 3.3V, and the spurious-free dynamic range (SFDR) is about 61.4dB when the quality factor is 40.Thirdly, the modeling of the on-chip spiral inductor is analized. Based on the Q-enhanced techniques of the negative resistance, an integrated RF active LC bandpass filter is presented. The simulated results show that the filter is used the TSMC 0.18μm CMOS process and the quality factor of the filter can be attained 60 and 15dB of noise figure at the center frequency 2.14GHz. The spurious-free dynamic range (SFDR) is about 56dB.Fouthly, according to the gyrator principle, the techniques that the inductor is simulated are based on CMOS process. A structure of the active inductor is presented, and it can be adapted to operating RF frequency band. A novel integrated circuit structure of the RF filter is presented based on the active inductor. As such, the layout of the filter is used the HJTC-0.18μm CMOS process and has been taped out. The measured results show that the filter centered at 2.44GHz with about 60MHz (-3dB) bandwidth is tunable in center frequency from about 1.92GHz to 3.82GHz, 1dB compression point is -15dBm when the DC power is consumed 10.8mW.The design of CMOS RF active continuous-time filters is the one of difficult problems about RF System on a Chip (SoC). Finally, the dissertation is summarized the research work and is given the own opinions and the suggestion about the research of the integrated RF continuous-time filters in future.