1. The problem statement, all variables and given/known data As shown in the attachment, a radio signal travels down a tunnel, reflected by the walls and floor. Assuming that at most 2 hops contribute, calculate the voltage Vab at A due to current Ib in antenna B. Obtain a formula that depends on various parameters of the problem. 2. Relevant equations Assuming antennas are polarization matched, the voltage Vab in receiver antenna A (effective length Ha) is given by Vab=Ha*Eb, where Eb (the field at A due to source at B) and Eb=((jωμIbHb)/4∏)*(exp(-jβd)/d) (where β is wavevector, d distance between A and B) 3. The attempt at a solution What I have got is for single reflection, the field at A due to source at B is Eb=R*((jωμIaHa)/4∏)*(exp(-jβd)/d) where R is reflection coefficient of ground and d the reflected distance. But for multiple reflection, just like shown in the graph, how I can get the field at A?