Some Results on Power in Passive Linear Time-Invariant Multiports, Part 3

We investigate a reciprocal and passive linear time-invariant multiport, having a port set coupled to a generator and a port set coupled to a load, in the harmonic steady state. Two configurations are considered, in which the port set at which the generator is connected and the port set at which the load is connected are exchanged. We improve earlier reciprocal theorems, and establish new results about the power available at output ports, and the bounds of the sets of the values of power transfer ratios, operating power gains, available power gains and unnamed power gains for all relevant excitations. The new results include five reciprocal theorems. One of them is used to generalize the Friis transmission formula.