An ultra-wideband (UWB) bandpass filter (BPF) using the hybrid microstrip and coplanar waveguide (CPW) structure is proposed in this article.The BPF composes of CPW feed lines and H-shaped microstrip resonator. By a CPW/microstrip back-to-back coupling structure, the UWB BPF was realized with the passband covering the entire UWB band (3.1-10.6 GHz). A narrow notched band achieved by etching slots on the lower impedance part of the H-shaped resonator to form an open circuit stub. At last, three U
