1. Slot antenna

2. Slot antenna
A slot antenna is a radiator made by cutting a one-half wavelength slot in a conducting sheet of metal or into the side or top of a waveguide.

3. Slot antenna
The slot antenna has the same characteristics as a standard dipole antenna, as long as the metal sheet is very large compared to λ at the operating frequency.
Slot antennas are widely used on high-speed aircraft where the antenna can be integrated into the metallic skin of the aircraft.

4. Slot antenna

5. Radiation pattern of Slot antenna
Far Field Components of Slot Radiation

6. Horn Antennas
flared waveguides that produce a nearly uniform phase front larger than the waveguide itself
constructed in a variety of shapes such as sectoral E-plane, sectoral H-plane, pyramidal, conical, etc.

7. E- and H-Plane Patterns of the E-Plane Sectoral Horn

8. E- and H-Plane Patterns of the H-Plane Sectoral Horn
E-Plane
H-Plane

9. E and H-Plane Patterns
E-Plane
H-Plane )

10. E- and H-Plane Patterns of The Conical Horn Antenna
E-Plane
H-Plane

11. Pyramidal Horn
combination of the E-plane and H-plane horns and as such is flared in both directions

13. Other horn antenna types
Multimode Horns
Corrugated Horns
Hog Horns
Biconical Horns
Dielectric Loaded Horns
etc.

14. Application Areas
used as a feed element for large radio astronomy, satellite tracking and communication dishes
A common element of phased arrays
used in the calibration, other high-gain antennas
used for making electromagnetic interference measurements