High-frequency Integrated Inductors Rapid Design Algorithm And Applications

With the development of Communication Technology and IC, the design and application of MMIC and RFIC become more and more frequent. It is noted that any kinds of ICs are basically constructed by four components: resistor (R), capacitor (C), inductor (L), and transistor (T). Among them, resistors and capacitors are easily analyzed and designed by simple formulas. Transistors are mainly modeled by measurement ways due to their process dependency and not easy scalability. Owing to the complicated parameters and complex high frequency analysis of inductor, it has been lacking a precise model and efficient CAD tools in integrated inductor design. Therefore, to design high-performance integrated planar spiral inductors has become a hotspot and difficulty in RFIC.As a very important kind of passive component, Inductor is widely used to achieve the function of turning,matching, filtering and feedback in RFIC. It's trend that the inductor is integrated into the chip. In this paper, first reviewed the development of integrated inductors with IC processes and the frequently-used planar spiral inductors in MMIC and RFIC, and then a single-Πmodel of spiral inductor is introduced. On this basis, in view of the insufficiency of full-wave analysis method in traditional electromagnetic field and physical inductor models, a numerical technique is proposed in this paper, which fits for any kinds of processes and structures, also its high-speed characteristic is good at online-EDA and engineering design. Considering the effects of geometric parameters and process parameters change on the inductance, the results calculated by this numerical technique have a good consistency with ADS simulation. This paper also analyzed the results, described the factor which influences the performance of the inductor, and then put forward a method to calculate the number of turns using interpolation with a given inductor value. After the analysis of different parameters, some main kinds of methods are suggested to improve the inductance and the maximum Q factor of planar spiral inductor. Finally, in view of the application of inductor in passive filter circuit, study the network synthesis in filter designing and give the steps of filter designing, then design the components parameters in three-order low-pass filter circuit with a 50ohm impedance using the Filter Design Guide of ADS, calculated the numbers of turns of the inductor adopting the interpolation proposed in this paper, used the formula of MIM capacitor to calculate the area of the metal poles, give the circuit layout, and carried out the simulation in ADS. The results proved to achieve the design demand compared with the ideal circuit.