We propose and experimentally demonstrate two simple solutions for power-efficient ultra-wideband (UWB) radio frequency (RF) system assisted by an electrical bandpass filter (EBPF). In the first solution, any optical Gaussian pulse with enough bandwidth is transmitted over optical fiber link, and then converted to a power-efficient UWB pulse by an EBPF with a passband of 3.1-10.6 GHz. The transmission and modulation of UWB signal is processed in optical domain, whereas the generation of UWB is processed in electrical domain. Both UWB modulations of on-off keying (OOK) and binary phase shift keying (BPSK) are experimentally demonstrated. In the second solution, the EBPF is used to convert any electrical waveform to a power-efficient UWB pulse. Then the electrical UWB pulse is converted to an optical UWB pulse with a Mach-Zehnder modulator (MZM), and then distributed over long haul fiber link. These two solutions embody the advantages of both low-loss longhaul transmission of optical fiber and mature electrical circuits. And the millimeter-wave UWB signal is also demonstrated.