|Image of the Elliptical-base strip monopole.|
High data speeds and multiband operations of modern wireless communication systems have significantly increased the demand for broadband antennas that are capable of supporting such requirements. In general, the systems need low-cost solutions with desired performance in terms of impedance bandwidth, polarization and gain. Planar monopole/dipole antennas fall into this category of antennas. Although they usually have a high profile above the ground-plane, they do enjoy broad bandwidth.
It should be noted that for mobile wireless applications, the antennas are expected to be embeddable or easily integrated into wireless devices. In system design, therefore, the antennas directly printed onto a printed circuit board (PCB) are the most promising designs, Volakis....
A planar circular disc monopole gives a better impedance bandwidth than the square monopole; however, the bandwidth may be improved by replacing the lower half of the square with a semicircular base. To achieve a more omnidirectional radiation pattern at all frequencies, a second orthogonal plate may be added.