antenna radiation resistance的意思|示意

Antenna radiation resistance is a key factor in antenna and antenna systems design. It is defined as the ratio of the radiated power to the total power flowing into the antenna. It is an important parameter in the analysis of the gain, directivity, and efficiency of an antenna, and is represented by the symbol Rrad.

Radiation resistance is affected by the elements’ geometrical shape, size and construction, as well as by their mutual coupling. It is also dependent on the feed arrangement and its impedances. In antenna systems, the radiation resistance includes both the real part (ohmic resistance) and the polarizability of the reactive part. The nominal radiation resistance for antennas is usually given in the datasheet and is based on the far-field behavior of the antenna.

In radio frequency (RF) systems, antenna radiation resistance is the main factor in determining the efficiency of the antenna. A high radiation resistance, in combination with a low ohmic resistance, is desired as this will result in a higher efficiency. This can be achieved by using an antenna with a small input impedance.

The radiation resistance also affects the gain of an antenna. A higher radiation resistance results in a higher gain, which is desirable in most applications. The antenna radiation resistance is also used to calculate the antenna loading. This is done by dividing the antenna’s feed point impedance by the radiation resistance. The result is the loading factor, which is used to calculate the total power that the antenna can handle.

In conclusion, radiation resistance is a key parameter in the design of antennas and antenna systems. It is used to calculate the gain, directivity and efficiency of the antenna, and is also used to determine the antenna loading. A high radiation resistance is desirable in most applications, as it results in higher efficiency and gain.