Abstract: This study presents an apparatus for detecting Ultra Wide-Band (UWB) impulse radio (IR) signals using circuit with a normal ultra-high-speed integrated comparator, which having nonlinear dynamics characteristics with the same N-shaped I-V characteristic as tunnel diode. This circuit is configured to generate amplified pulse in response to incoming weak UWB impulse radio signals by utilizing the negative resistance region of the I-V characteristic with differential input. It can provide higher symbol rate than correlation detector and is more stable, more feasible and less complicated than the tunnel diode detector. The experiment results indicate that the detecting sensitivity of this apparatus is approximate to that of the tunnel diode detector.