In this paper, we develop new mixed-mode implementations for particle filters and compare them to a digital implementation. The motivation for the mixed-mode implementation is to achieve low-power implementation of particle filters. The specific application considered is a bearings-only, single-target tracking algorithm. Specifically, we develop mixed-mode implementations that use analog components to realize nonlinear functions in the particle filter algorithm. The analog implementation of nonlinear functions uses low-power multiple-input translinear element (MITE) networks. Simulation results for one mixed-mode implementation of the bearings-only tracker show that the analog errors are low enough to support accurate tracking. Redesign of the mixed-mode implementation in a second form with more analog components will result in nearly twenty times less power dissipation.