Search results
Antennas 101 13 The Dipole - 1 •Oldest and simplest form of antenna –“Di” (two) “Pole” (voltage polarity) –Usually 1/2-wavelength long •Similar to a vibrating string’s fundamental –Current maximum in the middle –Voltage maximum at the ends •Pattern repeats every 1/2-wavelength –Direction or amplitude is reversed 2013
antennas. Some antennas may also be described as "omnidirectional", which for an actual means that it is isotropic in a single plane (as in Figure 1 above for the x-y plane). The third category of antennas are "directional", which do not have a symmetry in the radiation pattern.
1. Definition of the Antenna and Wave-Motion The radio antenna may be defined as the interface between a circuit in which electrical power is constrained to follow conducting paths, and electromagnetic radiation travelling freely through space. The antenna may convert power in the circuit into radiated energy or vice versa, forming either
This is the first in a series of videos on antennas and propagation. It is based on and supports a university course, but covers material without any deep math. In Episode #1 we overview key elements of radio antenna.
The center conductor of the feeding coaxial cable is connected to one side of the slot, and the outside conductor of the cable - to the other side of the slot. The slot length is some (λ/2) for the slot antenna and (λ/4) long for the INF antenna. The INF and the slot antennas behave similarly.
The problems listed below comes from Balanis’ book (3rd ed) and are the most rele-vant for this Antenna Theory course. Some of these problems will be solved on the blackboard during the tutorials and solutions will also be provided to other problems. Answers are given for most of the problems.
ANTENNAS. Antennas couple propagating electromagnetic waves to and from circuits and devices, typically using wires (treated in Section 3.2) or apertures (treated in Section 3.3).
