In this paper, a newly-developed pattern-diversity single patch antenna with improved operating bandwidth and isolation is present the working mechanisms of the radiation pattern and frequency reallocation are demonstrated at first then, to enhance the bandwidth, the effects of internal electric-field distributions on impedance matching are studied in detail the simulated results show that the proposed antenna can work over the frequency ranges of 5.69-5.87 GHz (3.1%) with better isolation. At the same time, the advantages like low-profile, compact size (0.53*0.39*0.04*λ03), and good diversity performance are still retained.