A conical horn is in the shape of a cone, with a circular cross section.
They are used with cylindrical waveguides.
What functions do conical horn antennas provide?
A conical horn antenna serves the same function for electromagnetic waves traveling through air that an acoustical horn does for sound waves in a musical instrument such as a trumpet or tuba. It provides a gradual transition structure to match the impedance of a tube (cylinder) to the impedance of free space, enabling the waves from the tube to radiate efficiently into space.
Conical horns can be used to experimentally determine the gain of other antennas by using the substitution method. The conical horn and the antenna under test are alternately connected to a well-matched detector system in order to compare their relative power levels. The power level difference is then added to the appropriate level of the calibration curve to determine the absolute gain of the antenna under test.
Where are conical horns used?
Conical horns are also useful as power monitors in radars transmitter test, known-gain radiators in field propagation studies, and transmitting or receiving antennas in test bench applications.
Conical design 𝑑 𝑚 = 2. 𝑎 ≃ 3𝜆𝑙 𝜆 = 𝑐 𝑓 𝐿 𝑠 ≃ 0.8 − 1.71𝑠 + 26.25𝑠2 − 17.79𝑠3 𝑠 = 𝑑 𝑚 2 8𝜆𝑙