The next evolution is happening under industry 4.0. For proper D2D communication, it is essential to know the reason for amplitude variation. Most of the channel characterization measurement \cite{8999798}, \cite{8999799} at mmWave frequency seems not to be able to distinguish between amplitude variations caused by fast fading and NLOS to LOS transitions. Existing RF directional channel characterization measurement method where RF tones are separated in such a fading is uncorrelated can categorize amplitude variation. In this project, a series of measurements have been performed. Data processing has been done on the collected data to analyze frequency correlation, K-factor, and multi-path spread. Based on data processing, coherence bandwidth is defined. The measurement results show that coherence bandwidth is higher when both directional receiver and transmitter are in Line of sight(LOS). The coherence bandwidth decreases as the separation between the transmitter and receiver increases in a rich fading channel. Coherence bandwidth decreases as a separation between RF tones increases.