An innovative transient study of RF and microwave circuit operating with bandpass (BP) negative group delay (NGD) function is devoted in this paper. The developed unfamiliar circuit BP-NGD analysis is applied to an original barcode-shape microwave passive topology. The design method of the BP-NGD barcode microstrip circuit is described. The circuit under study is implemented in order to operate as a tri-band NGD function. Furthermore, the different steps of the BP-NGD transient analysis adapted to triband aspect is explained. Before the time-domain (TD) testing, it is particularly important to define the transient parameters from the frequency domain analysis. In other words, the BP-NGD specifications of the circuit under test (CUT) must be determined. Similar to all RF and microwave circuits, the BP-NGD one is specified based on the S-parameter model. To realize the transient analysis, we have considered a Gaussian pulse as input signal in order to analytically define the TD characteristics in function of the NGD bandwidth (BW) and center frequency. The feasibility of the developed BP-NGD transient study is illustrated by experimentation based on ultra-wide band (UWB) pulse generator. As proof-of-concept, barcode NGD circuit exhibiting tri-band NGD value-center frequency-bandwidth, (-5.9 ns, 2.128 GHz, 20 MHz), 2.3 GHz, 14 MHz) and 2.42 GHz, 14 MHz), respectively, has been fabricated and tested. The transient simulations and experiences confirm the transient BP-NGD behavior. It is emphasized that the output signal envelopes of the barcode NGD prototype present leading and tailing edges in time-advance of input ones when the carrier frequency is equal to the NGD center frequency.