We present a microwave B-field scanning imaging technique using diamond microcrystal containing nitrogen vacancy center that is attached to a fiber tip. We propose a pulsed modulation technique, enabling the implementation of a variety of pulsed quantum algorithm for state manipulation and fast readout of spin state. A detailed mapping of the magnetic B-field distribution of a helical antenna with sub-100 micron resolution is presented and compared with numerical simulations. This fiber based microwave B-field probe has the advantage of minimized invasiveness, small overall size, will boost broad interest in a variety of applications where near field distribution is essential to device characterization, to name a few, antenna radiation profiling, monolithic microwave integrated circuits failure diagnosis, electromagnetic compatibility test of microwave integrated circuits and microwave cavity field mode mapping.