Three miniaturized lumped-element power dividers with a filtering function for use in quadrature mixers are described. Simulation results showed that they can be miniaturized, as compared to conventional ones with open/short stubs, while maintaining the filter characteristics. A fabricated 0.95-GHz 0° power divider with a filtering function had a chip size about half that of a conventional lumped-element one. Its insertion loss at 0.95 ± 0.05GHz was 4.0 ± 0.1dB.