Shunt Spiral Inductors

This article presents FEKO simulations that are representative of RF components that are constructed on a dielectric.  The model that is simulated here is a shunt coupled spiral inductor that was also analysed by Polycarpou et al [1].

Shunt coupled spiral inductor

Figure 1 depicts the shunt coupled spiral inductor and S-parameter results from [1, Figure 6].  Figure 2 presents the FEKO simulated model and results.  The model was constructed with CADFEKO and the substrate modelled as a semi-infinite plane Green's function.  The FEKO results compare favourably with the published results  [1, Figure 6], validating the FEKO model and simulation techniques.  Small differences in the results are due to uncertainties in the model dimensions between the published model and the FEKO model, e.g. length of the main transmission line, exact dimensions of the right angle coupling between the spiral and the w₃ line from the main transmission line.

Figure 1:  Simulation model and results, [1, Figure 6]	Dimensions
	Alumina substrate: εr = 9.8 h = 0.635 mm w1 = 0.635 mm w2 = 0.2 mm w3 = 0.6 mm R1 = 1.9 mm R2 = 1.3 mm R3 = 0.7 mm

Figure 2:  FEKO shunt coupled spiral inductor simulation
(a) Model (b) Computed S-parameters

The results from [1] are for a FEM full-wave solution.  By comparing the FEKO results to the published FEM results and getting the degree of correlation shown in Figure 2(b), it is reasonable to assume that the results are accurate for the real-world problem being analysed.