Table 2.

The performance of Neural fitting algorithms for permittivity estimation.

Algorithm name	Network size	Results	RMSE	R2
Levenberg–Marquardt	17	Training	2.6	0.93
Levenberg–Marquardt	17	Validation	2.8	0.91
Levenberg–Marquardt	17	Testing	2.7	0.92
Levenberg–Marquardt	10	Training	2.9	0.91
Levenberg–Marquardt	10	Validation	3.1	0.89
Levenberg–Marquardt	10	Testing	3.5	0.90
Levenberg–Marquardt	50	Training	2.4	0.94
Levenberg–Marquardt	50	Validation	2.2	0.91
Levenberg–Marquardt	50	Testing	2.4	0.95
Bayesian regularization	10	Training	2.7	0.92
Bayesian regularization	10	Validation	2.5	0.92
Bayesian regularization	10	Testing	2.6	0.92
Scaled conjugate gradient	10	Training	3.0	0.90
Scaled conjugate gradient	10	Validation	2.7	0.84
Scaled conjugate gradient	10	Testing	3.1	0.89