What is the directivity of a monopole antenna?
The directivity of the quarter wave monopole antenna was found to be 4.6dB which is almost twice 2.43dB of the full- wave loop antenna. Also, the directive gain of the quarter wave monopole antenna was found to be 1.96 dB higher than that of the full-wave loop antenna which was found to be -0.22dBd.
Why do we use monopole antennas while having dipole antennas?
The reason for this is simply because no radiation occurs below the ground plane; hence, the antenna is effectively twice as “directive”. Monopole antennas are half the size of their dipole counterparts, and hence are attractive when a smaller antenna is needed.
What is the relation between gain and directivity?
By definition, directivity is the ability of an antenna to focus the radiation to a particular direction, whereas, the gain is the ability of the antenna to convert the input power into radio waves in a particular direction.
How is the directivity of a monopole antenna related?
The directivity of a monopole antenna is directly related to that of a dipole antenna. If the directivity of a dipole of length 2L has a directivity of D1 [decibels], then the directivity of a monopole antenna of length L will have a directivity of D1+3 [decibels].
What is the impedance of a quarter wave monopole?
For a quarter-wave monopole ( L =0.25* ), the impedance is half of that of a half-wave dipole, so Zin = 36.5 + j21.25 Ohms.
Can a quarter-wavelength monopole be used on an infinite ground plane?
Quarter-wavelength monopole Antenna on Infinite Ground Plane Note: λ/4 length is only valid when ground plane size is infinite λ∕4 monopole on infinite electric conductor Equivalent λ∕2 dipole Monopole Antenna on Infinite Ground Plane Far-fields E and H for the λ/4 monopole above the ground plane are same as that of dipole antenna
Which is one half of a dipole antenna?
A monopole antenna is one half of a dipole antenna, almost always mounted above some sort of ground plane. The case of a monopole antenna of length L mounted above an infinite ground plane is shown in Figure 1 (a).