“…The equations are intentionally arranged in a structured way that allows to visually follow the flow of electromagnetic energy through distinct parts of the communication channel. Unlike the recently proposed antenna equation [10], the present approach aims at symmetric arrangement with the TX and RX antennas characterized by the same quantity, in the best tradition of the well-established Friis' transmission equation. Besides, the notation of the involved phasor quantities utilizes a simple accent, the tilde (˜), which, thanks to its shape ("wave"), gives a hint that the particular quantity is based on power wave theory.…”