Ad
related to: antenna half-wave dipole meter calculator chart
Search results
Results from the WOW.Com Content Network
German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitative end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna.
It is the total power in watts that would have to be radiated by a half-wave dipole antenna to give the same radiation intensity (signal strength or power flux density in watts per square meter) as the actual source antenna at a distant receiver located in the direction of the antenna's strongest beam . ERP measures the combination of the power ...
The electric field strength at a specific point can be determined from the power delivered to the transmitting antenna, its geometry and radiation resistance. Consider the case of a center-fed half-wave dipole antenna in free space, where the total length L is equal to one half wavelength (λ/2). If constructed from thin conductors, the current ...
The most common form of log-periodic antenna is the log-periodic dipole array or LPDA, The LPDA consists of a number of half-wave dipole driven elements of gradually increasing length, each consisting of a pair of metal rods.
[70] [123] [71] If the ground plane is large enough, the radio waves from the remaining upper half of the dipole (a) reflected from the ground plane will seem to come from an image antenna (b) forming the missing half of the dipole, which adds to the direct radiation to form a dipole radiation pattern. So the pattern of a monopole over a ...
Since this factor is not related to the radio wave path but comes from the receiving antenna, the term "free-space path loss" is a little misleading. Directivity of receiving antenna- while the above formulas are correct, the presence of Directivities Dt and Dr builds the wrong intuition in the FSPL Friis transmission formula. The formula seems ...
Hence, the monopole antenna has a radiation pattern identical to the top half of the pattern of a similar dipole antenna, and a radiation resistance a bit less than half of a dipole. Since all of the equivalent dipole's radiation is concentrated in a half-space, the antenna has twice the gain (+3 dB) of a similar dipole, neglecting power lost ...
When the antenna is fed at a point of maximum current, as in the common center-fed half-wave dipole or base-fed quarter-wave monopole, that value is mostly the radiation resistance. However, if the antenna is fed at some other point, the equivalent radiation resistance at that point R r a d 1 {\displaystyle \ R_{\mathsf {rad\ 1}}\ } can easily ...
Ad
related to: antenna half-wave dipole meter calculator chart