Antenna Gain is an important parameter for measuring the radiation capability of an antenna. It describes the radiation efficiency of the antenna in a specific direction relative to a reference antenna (usually an omnidirectional antenna or an ideal dipole). Gain represents the ability of the antenna to focus input power in a certain direction or to receive signals from a certain direction, usually expressed in decibels (dB). Antenna gain considers not only the radiation efficiency of the antenna itself but also the effect of signal concentration in a certain direction due to antenna design. High-gain antennas can more effectively concentrate energy in a smaller radiation area, which means the signal in that direction will be stronger, while signals in other directions will be weaker. Specifically: Omnidirectional antennas (such as those on typical Wi-Fi routers) provide a uniform radiation pattern on the horizontal plane, with relatively low gain, but can cover uniformly in all directions. Directional antennas (such as satellite dish antennas or Yagi antennas) provide high gain, allowing signals to be concentrated in one direction, enabling communication over longer distances. High-gain antennas are particularly useful in wireless communications because they can enhance the ability to receive or transmit signals over long distances, improving the quality and reliability of communication. However, gain is not the only factor in measuring antenna performance; other parameters such as the operating frequency, bandwidth, size, and installation location of the antenna also need to be considered in practical applications.