For outdoor long-distance point-to-point backhaul, the antenna of () should be selected.

Outdoor long-distance point-to-point (P2P) wireless bridging and backhaul applications require highly directional energy focusing to overcome severe space propagation path loss across multi-kilometer distances. Antennas characterized by high gain provide the necessary equivalent isotropically radiated power (EIRP) to maintain line-of-sight signal integrity over long ranges. Furthermore, a small lobe width (narrow beamwidth) concentrates radio frequency energy in a narrow beam directly toward the target destination. This narrow radiation pattern minimizes side-lobe interference, isolates the link from external wireless signals, and improves overall link reliability and signal-to-noise ratio across long spans.

B: Large lobe width scatters RF energy over wide angles, reducing range and introducing co-channel interference from adjacent directions. C: Omnidirectional antennas radiate signal in 360 degrees, providing low gain and causing severe interference in long-distance point-to-point bridging. D: Low gain and large lobe width fail to overcome path loss over long distances and dissipate RF energy unnecessarily.

- Huawei Technologies Co., Ltd., "WLAN Antenna Selection and Placement Guide," Document Version 04, Section: Outdoor Point-to-Point Wireless Bridging Principles.

- Huawei Technologies Co., Ltd., "HCIA-WLAN V3.0 Training Manual," Chapter 3: WLAN Antenna Technology and Application Scenarios.