Passive Gain describes the increase of RF energy in an intentional direction using an antenna. This occurs by focusing or directing the output power without requiring an external power source, leveraging the internal workings of the antenna to enhance the signal strength in a specific direction.

Patch and panel antennas are commonly used by indoor Wi-Fi devices in a MIMO multiple spatial stream implementation. These types of antennas provide the necessary directionality and coverage within indoor environments, ensuring multiple spatial streams can be effectively utilized. Dipole antennas are not directional while grid, sector, and dish antennas are more commonly used in outdoor or large-area implementations rather than indoor environments.

Horizontal and vertical beamwidth are calculated at the points where the main lobe decreases power by 3 dB. This definition is standard in RF engineering, where the 3 dB point is used to define the beamwidth of an antenna.

The link budget calculation for an outdoor point-to-point WLAN bridge link typically includes factors such as operating frequency, receive antenna gain, and transmit power. MU-MIMO (Multi-User Multiple Input Multiple Output) capabilities of the bridges are not directly considered when calculating the link budget, as it primarily deals with how signals are transmitted and received in a multi-user environment rather than the basic power and gain parameters within a point-to-point link.

WPA2 is a certification created by the Wi-Fi Alliance that validates devices correctly implement CCMP/AES. This certification ensures that devices are compliant with a specific level of security required for wireless networks.