The Study of Radio Frequency CMOS Active Inductors and Applications

• Main Authors: Yang Jenn Tzer, 楊鎮澤
• Other Authors: Lee Chen Yi
• Format: Others
• Language: en_US
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/hp54d7

博士 === 國立交通大學 === 電子工程系所 === 94 === In this thesis, we will focus on the research illustration and design comparison on combing several different CMOS active inductor with negative conductance generator (NCG) applied in RF amplifier on different operating frequency. And we will apply various loss compensation techniques on several different active inductors to improve the characteristics of the inductors. Furthermore, we applied the improved active inductor on the wideband amplifier and the voltage-controlled oscillator to prove that using the active inductors in RF can have more advantages than using the planar spiral inductor. For example, the active inductor can have a higher quality factor, a higher operating frequency, and a higher inductance etc. On the other hand, in radio frequency circuit design, the size of the chip used in an active inductor will be much smaller than the one used in a planar spiral inductor. The design of the use of the planar spiral inductor applied on the radiofrequency amplifier will be described at the beginning of the thesis. Though the above design shows the result of performing good characteristics, some disadvantages of this design also exist. For example, the size of the chip of the circuits using planar spiral inductor too large, quality factor is too low, and the characteristics of the inductor cannot be controlled easily and accurately. We presented the use of the active inductor to improve the disadvantages mentioned above. We applied the techniques of the negative conductance generator, which combines the existing active inductor and the characteristics of the improved inductor, to work on the different bandwidth radio frequency. From the simulation results, we found that the output power gain is over 17dB, and the noise figure is lower than 6dB. The simulation also shows that the results are very close to those using the planar spiral inductor, and the size of circuit using the active inductor design is one forth of that using planar spiral inductor. Moreover, the power consumption decreases dramatically when using active inductor. So, we can conclude that using active inductor generates more benefits than using planar spiral inductor. For minimizing the complexity of the active inductor circuits, we present several simple compensated circuits for each different active inductor to reach the goals of performing higher performance and an easy design circuit. From the mathematical analysis, simulated results, and measured results, the improved active inductor can obtain a very high quality factor, which is above 104. Finally, we present the results of applying the improved active inductor in the circuits of wideband amplifier and voltage-controlled oscillator. From the wideband amplifier’s point of view, the amplifier can generate a flat gain, which is about 18dB, in the bandwidth from 0Hz to 1GHz. From the voltage-controlled oscillator’s point of view, the voltage-controlled oscillator can generate a wide tuning range from 1GHz to 3GHz, -98dBc/Hz phase noise and steady 10mW power consumption. As the result, we can conclude that using active inductor in the radio frequency is a workable solution via the approach mention above. This solution also saves us a lot of cost taken by the size of the chip during the design stage of the radio frequency.