However a parasitic elements interact with the electromagnetic field in order to realize a fairly directional antenna but one which is limited to a rather narrow bandwidth.
22.
The most commonly seen manifestations of parasitic elements in components are in the parasitic inductance and resistance of the component leads and the parasitic capacitance of the component packaging.
23.
A Yagi antenna for UHF TV reception with 21 parasitic elements; 4 reflectors attached to the vertical bracket at left, and 17 directors attached to the horizontal beam at right.
24.
Conveniently, the parasitic elements have a RF voltage ) at their centre, so they can be attached to a conductive metal support at that point without need of insulation, without disturbing their electrical operation.
25.
Few people would ever feel an urgent need to answer the question, " What are the parasitic elements of a Yagi antenna ? " or to identify all the causes of " splatter interference ."
26.
Some feedback, positive or negative, is unavoidable and often undesirable introduced, for example, by parasitic elements, such as inherent capacitance between input and output of devices such as transistors, and capacitive coupling of external wiring.
27.
One way of thinking about the operation of such an antenna is to consider a parasitic element to be a normal dipole element fed at its centre, with a short circuit across its feed point.
28.
The fact that the parasitic element involved is not exactly resonant but is somewhat shorter ( or longer ) than ? / 2 modifies the phase of the element's current with respect to its excitation from the driven element.
29.
Antennas typically consist of a feed and additional reflecting or directive structures ( such as a parabolic dish or parasitic elements ) whose function is to form the radio waves from the feed into a beam or other desired radiation pattern.
30.
It is widely thought that the genetic material that encodes meganucleases functions as a parasitic element that uses the double-stranded DNA cell repair mechanisms to its own advantage as a means of multiplying and spreading, without damaging the genetic material of its host.
