A correspondent asked about the difference between two small untune loops mentioned in two of my articles, this article explains.
Firstly lets set the context, a small loop means less than λ/10 perimeter, and untuned is to mean that the loop is loaded directly, in this case by a receiver which we will assume has an input impedance of 50+j0Ω.
Let’s look at the two cases. The key difference is in the connection at the gap:
- the first has a short circuit coaxial stub of half the perimeter between the inner conductor at the right side of the gap and the outer surface of the outer conductor at the right side of the gap; and
- The second directly connects the inner conductor at the right side of the gap and the outer surface of the outer conductor at the right side of the gap.
Small single turn un-tuned shielded loop
Above is a diagram of the loop. Continue reading Differences in two similar simple untuned small loop configurations