Conductively coupled means any type of coupling that allows for current to flow. US3879735A en.
A different sort of end-fire array which is much more often used is based on the use of so-called parasitic elements. This is placed in the radiating element.
DE3703812A1 en. These have a very low radiation resistance and a high capacitive reactance making them inefficient antennas. US8866691B2 en.
It can be seen that in fact VSWR is minimum very very close to resonance, due to the fact that reactance changes quickly near resonance whereas resistance changes relatively slowly. Tube caps may be utilized to keep material out of the inner portions of the tubes. The folded dipole has a wider bandwidth than a single dipole.
Insulatively coupled means any type of coupling that attempts to prevent current flow. In this case one uses dBi instead of dBd see decibel. In many cases the dipole loss resistance is ignored as it may be low.
This shows that the antenna is optimally feed with a 100-ohm source.
Matching Problems using a tuner and high impedance feedline. Yagi-Uda antenna. However they can nevertheless be practical receiving antennas for longer wavelengths. The quarter-wave conductor and its image together form a half-wave dipole that radiates only in the upper half of space.
Radiation pattern of vertical half-wave dipole; vertical section. It is formed by a conductor in length, fed in the lower end, which is near a conductive surface which works as a reflector see effect of ground and is an example of a Marconi antenna.