According to an exemplary embodiment, an interposer structure for electrically coupling a semiconductor die to a support substrate in a semiconductor package includes at least one through-wafer via extending through a semiconductor substrate, where the at least one through-wafer via provides an electrical connection between the semiconductor die and the support substrate. The interposer structure further includes a passive component including a trench conductor, where the trench conductor extends through the semiconductor substrate. The passive component further includes a dielectric liner situated between the trench conductor and the semiconductor substrate. The passive component can further include at least one conductive pad for electrically coupling the trench conductor to the semiconductor die. The passive component can be, for example, an inductor or an antenna.