Compact Capacitor Antennas

"COMPACT CAPACITOR ANTENNAS his 30-chapter eBOOK of more than 215 pages is a publication by antenneX with a collection of papers written by some of the best and most active experts in the design, development and construction of compact antennas based on a technology, the name of which was coined at antenneX — the capacitor antenna. "

Cool, seems like it relates to that antenna that's talked about with plates at either end, shaped like arrow heads, and a loading coil at the center.

I don't buy e-books, just physical ones, but I looked up some of the terms in the chapter titles and was led to some interesting reading.

The main idea of the capacitor antenna versus a whip with a top hat is the capacitor plates are solid, and pretty close to one another.

"Parallel plates
So far, this article is about the capacitance of a loose piece of metal. One could consider this as a capacitor with that piece of metal as one connection and an infinitely large sphere, infinitely far away around it as the other connection.

However, practical capacitors always consist of two plates near each other, and in fact there's a well-known formula for the capacitance of two parallel metal plates in air: C=ε0A/d, where A is the area of the plates and d their distance. We see that in this case the capacitance is proportional to the area of the plates, and not to their circumference as in the case of a single metal plate. This difference is caused by the presence of that second plate. Both plates have charges of opposite sign; the positive charge on one plate attracts the negative charge on the other plate. If both plates are very close, this effect is stronger than the mutual repulsion which in the case of a single plate causes the charge to sit mostly at the edge of the plate. As a consequence, in a parallel-plate capacitor the charge distributes itself evenly over the surface, and thus the entire surface contributes to the capacitance. "

From: www.pa3fwm.nl/technotes/tn08b.html

Boomer