Design and development of a novel Ultra Wide Band (UWB) panel Radar Absorbing Material (RAM) with Radar Cross Section Reduction (RCSR) of 10 dB (minimum) from 1.7 GHz. to 25 GHz. using hexagonal resistive patch Frequency Selective Surface (FSS) is presented in this paper. The four layers RAM is analyzed using transmission line model (TLM) and full-wave analysis of the design is carried out using HFSS v15 simulation software. The resistive FSS layers are designed as electrically very thin PCBs using 0.2 mm thick FR4 substrate. The prototype RAM is developed as a panel of size (280 mm x 280 mm). The thickness of panel RAM is 16.8 mm. and the weight is 190 gm. Monostatic RCS measurements are carried out on RAM in microwave anechoic chamber. Experimental and simulation results agree very well.