A root locus with respect to the active parameter for any second-order active RC filter is circular with center on the real axis. It is shown that for any pole pair

and pole frequency

, the circular root locus centered at

on the real axis and of radius

exhibits zero

-sensitivity and zero gain-sensitivity product (GSP) with respect to the active parameter. Furthermore, realization techniques to achieve zero

-sensitivity and zero GSP for prescribed

and

are outlined. Experimental results agree closely with the theoretical expectations.