Highly-direction antennas
. . . .

---

Highly-directional antennas

• Highly directional antennas are strictly used for point-to-point communications,
• Typically to provide network bridging between two buildings.
• Even slight movement of a highly directional antenna can cause the RF beam to be aimed away from the receiving antenna, interrupting RF communications.
• There are two types of highly directional antennas: parabolic dish antennas and grid antennas:
  
  
• Parabolic Dish Antenna
  • The parabolic dish antenna is similar in appearance to the small digital satellite TV antennas that can be seen on the roofs of many houses.
• Grid Antenna
  • The grid antenna resembles the grill of a barbecue, with the edges slightly curved inward. The spacing of the wires on a grid antenna is determined by the wavelength of the frequencies that the antenna is designed for.
  • Grid antennas, because of the spacing between the wires, are less susceptible to wind load and may be a better choice.
    

---

Reference:
Coleman, David D.,Westcott, David A. CWNA: Certified Wireless Network Administrator Official Study Guide: Exam CWNA-106 Wiley.