Contents
What is the polarization of monopole antenna?
Due to the imaging principle, the polarization of radiation and radiation patterns of a monopole antenna is the same as that of its equivalent dipole antenna. However: the monopole antenna has a field only in the top half of the space, having zero radiation below the ground plane.
What is the difference between monopole antenna and dipole antenna?
In essence, the difference between a monopole and dipole antenna, is that a dipole antenna uses an additionally radiator to generate a synthetic ground plane between the symmetric radiator elements, where a monopole antenna requires a physical ground plane. Dipoles tend to be more common.
What are the radiation impedances of a monopole antenna?
The Corresponding Equivalent Dipole Structures Employing Image Theory For example, if the length of the monopole antenna L − λ 0 /4, such that the corresponding length of the equivalent dipole antenna is λ 0 /2, the following values of the radiation impedances result:
How are the currents of a monopole and a dipole the same?
Notice in Figure 6.14 that for the currents in the monopole and dipole structures to be the same, one needs the source voltage of the equivalent dipole antenna to be twice that of the monopole antenna. As a result, the input impedance of the monopole structure is half that of the corresponding dipole structure: FIGURE 6.14.
Which is half of a dipole antenna do you need?
Here, only half of the dipole antenna is needed for operation. A metal ground plane (ideally of infinite size) is used, with respect to which the excitation voltage is applied to the half structure. The half structure for a regular dipole antenna is called a monopole antenna, in reference to the presence of only one physical side.
What is the length of a quarterwave monopole antenna?
The approximate, physical length of a printed quarterwave monopole antenna is then = 250/4 = 62.5mm provided that the size of the available ground plane is close to the ideal as discussed above and that the antenna trace is uniformly surrounded by the FR4 substrate.