Another look at power transfer.

Note high efficiency occurs when Rs<<Rl.

P = I^2 * R therefore low Rs = low lose and high Rl = higher power out.

 Simple enough with resistive  circuit.

 

Now consider the AC circuit. ONLY resistance consumes power. Reactance absorbs and releases power. Z matching does not means setting the input and output equal, unless we want to lose half our power in the source. 60 years ago we would neutralize a circuit which meant adjust for phase shift. Reactance produces phase and imaginary power. Zero phase shift means resistive load and true power dissipation. So neutralize the circuit and set the phase angle to zero to get power transfer.

60 years ago neutralize the circuit. Today conjugate the reactance.  In neither case are we setting Ri = Rl.

Food for thought.

In the last post I said "TUNE" the ground and "TUNE" the antenna.

Would be better to say NEUTRALIZE the circuit reactance.

R + i0 feeding R + i0 provides maximum power transfer. 

Low R feeding high R for best efficiency.

Years ago the device was named a tuner and that is how we describe it.