A　design　of　single-layer　single-feed　dual-frequency　patch　antenna　with　different　polarizations　is　presented　for　the　first　time.　The　structure　of　the　proposed　antenna　is　a　single　layer　patch,　which　mutually　nested　inside　and　outside　patches　and　connected　together　with　four　conducting　strips.　Two　operating　frequencies　of　the　proposed　antenna　can　be　observed　in　the　simulated　and　measured　results.　The　inside　patch　operates　at　the　high　frequency　and　outside　square　patch　operates　at　the　low　frequency.　The　center　frequency　of　the　antenna　prototype　for　Global　Positioning　System　(GPS)　is　1.575　GHz　with　circular　polarization　and　2.4　GHz　for　Wireless　Local　Area　Networks　(WLAN)　with　linear　polarization　respectively.　The　impedance　bandwidth　and　axial　ratio　of　the　proposed　antenna　is　studied　through　electromagnetic　simulations　and　measurements.