A Novel Active Inductor with High Q Factor and Inductance and Mutually Independent Tuning Characteristic

In this paper, a novel Active Inductor (AI) with high quality factor Q, high inductance L and mutually independent tuning characteristic is presented. It is mainly composed of three circuit blocks, and each circuit block is configured with an external voltage tunable terminal respectively. The high Q factor is achieved through the multiple MOSTETs negative resistance generation network connected between the positive and negative transconductors. Meanwhile, the high inductance is realized by the MOSFET variable capacitance block and the negative transconductor of the gyrator-C network in parallel. Additionally, the mutually independent tuning of Q and L each other is accomplished by coordinately varying three external tunable terminal voltages in three circuit blocks. Based on TSMC 0.18μm CMOS process, the novel AI is verified by Advanced Design System (ADS). The results show that at 4.8GHz, the peak Q factor can reach high up to 4086.06, and the inductance is as high as 273.62nH; at 4.5GHz, 4.8GHz and 5.1GHz, the Q value can be tuned greatly from 341.90 to 433.80, from 800.11 to 4086.06 and from 210.23 to 305.71 respectively, whereas the variation of L value is only 0.59%, 0.66% and 0.73%; Furthermore, under 4GHz, 4.8GHz and 5.4GHz, the L value can be tuned noticeably from 220.95nH to 247.72nH, from 298.00nH to 344.90nH and from 418.88nH to 511.34nH respectively, while the variation of the Q value is only 0.54%, 0.65% and 0.83%.