Is the Friis Formula outdated?
Is the Friis Formula outdated?


Well, you probably can say the Friis formula doesn't work so well when the EM wave hasn't fully formed and the impedance (as E/H) isn't 377 ohms but, it's not expected to work that well in the near field or on the borderline.

So, is the Friis formula outdated? No, because in the far field it works as expected and will be continued to be used.

Have you shown that another formula is simpler in the far field? I can't see that you have. Have you shown that another formula is more accurate in the far field? No I can't say that what you have said is convincing.

I would be very interested to see how the two formula outcomes converge mathematically (or numerically) but I'm unsure that your table is demonstrating that. Maybe it isn't meant to demonstrate that?

Another thing that puzzles me about the table of numbers is that you haven't demonstrated that you have factored-in the fixed antenna length of 1 metre. Clearly, at about 75 MHz a quarter wave monopole is tuned at 1 metre length but, like I said, your table doesn't show how you have factored this in at lower frequencies where it's impedance becomes very capacitive. 

Don't get me wrong on this, I'm not trying to be picky; I'm just trying to understand what your table fully reflects in the real world (not that the friis equation is all-together real-worldly).