what is monopole antenna
what is monopole antenna?
how we call a monopole antenna as monopole antenna?
is it because it has very small ground plane? Does ground plane have any relation with the size of the patch?
a square shape slot in the ground plane can be called as monopole antenna?
A monopole antenna needs a large (ideally infinite) ground plane, otherwise it's a kind of dipole.
Monopole antennas are a simplified arrangement of a dipole, which employs on base some reflector apparatus to reflect on it the radiation generated from the upper rod, so that the resultant radiation pattern viewed by remote receiver looks almost as becoming from a dipole. as illustrated on this post:
Which type of Antenna have onmidirectional?
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square shaped slot could be slot antenna in SIW (substrate integrated waveguide).
You can read about ultra wideband microstrip antennas and substrate integrated waveguides.
There are many pictures in google that can give idea about microstrip monopoles. Just google for microstrip monopole, microstrip ultra wideband, etc. and see images.