Search results
Results From The WOW.Com Content Network
When considering an antenna's directional pattern, gain with respect to a dipole does not imply a comparison of that antenna's gain in each direction to a dipole's gain in that direction. Rather, it is a comparison between the antenna's gain in each direction to the peak gain of the dipole (1.64). In any direction, therefore, such numbers are 2 ...
Ruze's equation is an equation relating the gain of an antenna to the root mean square (RMS) of the antenna's random surface errors. The equation was originally developed for parabolic reflector antennas, and later extended to phased arrays. The equation is named after John Ruze, who introduced the equation in a paper he wrote in 1952. [1]
The term gain has a different meaning in antenna design; antenna gain is the ratio of radiation intensity from a directional antenna to / (mean radiation intensity from a lossless antenna). Graph of the input v i ( t ) {\displaystyle v_{i}(t)} (blue) and output voltage v o ( t ) {\displaystyle v_{o}(t)} (red) of an ideal linear amplifier with a ...
The commonly quoted antenna "gain", meaning the peak value of the gain pattern (radiation pattern), is found to be 1.5~1.76 dBi, lower than practically any other antenna configuration. Comparison with the short dipole
An antenna designer must take into account the application for the antenna when determining the gain. High-gain antennas have the advantage of longer range and better signal quality, but must be aimed carefully in a particular direction. Low-gain antennas have shorter range, but the orientation of the antenna is inconsequential.
An antenna's directivity is greater than its gain by an efficiency factor, radiation efficiency. [1] Directivity is an important measure because many antennas and optical systems are designed to radiate electromagnetic waves in a single direction or over a narrow-angle.
Note that for a given antenna feedpoint impedance, an antenna's gain or increases according to the square of , so that the effective length for an antenna relative to different wave directions follows the square root of the gain in those directions. But since changing the physical size of an antenna inevitably changes the impedance (often by a ...
The gain increases with the square of the ratio of aperture width to wavelength, so large parabolic antennas, such as those used for spacecraft communication and radio telescopes, can have extremely high gain. Applying the above formula to the 25-meter-diameter antennas often used in radio telescope arrays and satellite ground antennas at a ...