Sumários

Horn antennas

12 junho 2025, 11:30 • Mário Silveirinha

Horn antennas. Field on the aperture. Radiated far-field. Impact of the phase error on the aperture and optimal horn.


Resolution of the problems, 3, 15, and 17, of set 4.

End of the course.

Log-periodic antennas. Spiral Antennas. Aperture antennas. Love's equivalence principle. Field radiated through a rectangular aperture on a screen.

11 junho 2025, 14:30 • Mário Silveirinha

Extra class lectured on 9 June:

Log-periodic antennas. Spiral Antennas. Problem 14, set 4.

Class lectured on 11 June:

Aperture antennas. Love's equivalence principle. Fields radiated by an aperture. Field radiated through a rectangular aperture on a screen. Aperture efficiency, directivity, and half-power beamwidth.

Frequency independent antennas. Biconical antenna.

6 junho 2025, 12:00 • Mário Silveirinha

Frequency independent antennas. 


Biconical antenna. Radiation pattern, directivity and input impedance.

Problem 13 of set 4.

The loop antenna

5 junho 2025, 11:30 • Mário Silveirinha

Resolution of problem 10.c) and 10.d), set 4.


The loop antenna. Far-field and effective height of a small loop antenna. Equivalent magnetic dipole. Field lines, radiation pattern, directivity, directive gain.

Helix antenna

4 junho 2025, 14:30 • Mário Silveirinha

Helix antenna: normal and axial modes.


Field radiated in the axial mode: equivalent array and radiation for a single helix turn. Radiation pattern, gain, input impedance and half-power beamwidth.

Problem 10.a) and b), set 4.