On the Radiation Resistance of Planar Monopole Antennas

On the Radiation Resistance of a Planar Monopole Antenna With Reduced Groundplane

“…the monopole length is presented for five values of the ground plane width ( from to by step of ) in three cases corresponding to ground plane lengths of , , and . It can be seen that substantially high values (i.e., comparable to the semi-infinite ground plane case [9]) are maintained as long as . The latter condition, however, seems unnecessary for intermediate lengths (see in Fig.…”

“…7), fields radiated by the vertical arm are multiplied by , which corresponds to the ratio between integrated currents for this trapezoidal distribution and those for a linear distribution. Based on the study presented in [9] on radiation resistance of dipoles parallel to the ground plane edge, we assumed that the horizontal arm has a negligible contribution to the radiation resistance for very small values of . Starting from (12) and (13), this provides the corrected expressions for radiation resistance for long and wide configurations, respectively…”

“…In particular, inverted-L and inverted-F planar antennas [6]- [8], obtained by laying the radiating monopole parallel to the ground plane and protruding from the edge, are excellent candidates for compact antennas in many situations. In [9], the radiation resistance of short planar monopole antennas with a semi-infinite ground plane was investigated by means of the theory of diffraction, and an analytical solution was presented. It was found that the radiation resistance grows linearly instead of quadratically with antenna length, which leads to substantially high values, even for very small lengths.…”

“…1), where the small ground plane is very long or very wide . In both configurations, the analytical model presented in [9] is extended based on a triangular distribution approximation for currents. The remainder of this letter is organized as follows.…”