An improved gyrator-capacitor architecture based high quality-factor active inductor with joint positive and negative feedback loops for various radio-frequency bands operation

An improved gyrator-capacitor (GC) architecture of active inductor (AI) is proposed, which consists of a dualloop configuration, mainly including a negative feedback loop (NFL) and a positive feedback loop (PFL) and hence is denoted as positive-negative-feedback-GC (PNF-GC). The in-depth cooperation of above dual-loop configuration in conjunction with the dynamically and synergistically tuning of external voltages in different building modules ensure high Q values under low-frequency range and alleviate the degradation impact of the parallel conductance Gp on Q values under high-frequency range, and thereby the proposed PNF-GC architecture can make a single AI achieve high Q values under various radio-frequency bands. Subsequently, based on the TSMC's 0.18-mu m CMOS process, a prototype circuit of AI based on PNF-GC architecture as an exemplary example and its layout are given, so as to demonstrate the performance under quad bands including X, C, S and L bands. The results from post-layout simulation indicate that within the frequency range of the X-band (8-12 GHz), the Q values are all higher than 20, with a maximum Q value of 1068 at 10.2 GHz; within the C-band (4-8 GHz), the all Q values exceed 50 and the maximum Q value reaches 1006 at 6 GHz; within the S-band (2-4 GHz), the all Q values surpass 250, with a peak Q value of 1033 at 3 GHz; and within the L-band (1-2 GHz), the Q values are all higher than 590 and a peak Q value of 1026 appears at 1.5 GHz. The above proposed PNF-GC architecture of AI, which makes a single AI have an ability to obtain high Q within a wide frequency range, is of important significance to frequency reconfigurability of miniaturized RFICs.