Rectangular Monopole with Trident Shaped Feed
Image of the Rectangular Monopole with Trident Shaped Feed.

UWB applications are being used in many industries today. These applications require low cost solutions with wide frequency band operations. Planar monopoles (realised by replacing the wire element of a conventional monopole with a planar element) are a family of antennas which are able to meet these specifications.

This variation of the standard rectangular (trapezoidal) planar monpole antenna has a modified feed to achieve ultra-wideband performance. The three branched symmetrical (trident) feed leads to a more uniform current distribution at the base of the monopole element. This feed creates an intense vertical current distribution while suppressing the horizontal current distribution leading to better polarisation properties and impedance bandwidth of the monopole. A good reflection response (VSWR < 2 (S11 < -10dB)) across a bandwidth of more than 8:1 is achieved.

VSWR comparison between different monopole topologies
Total gain: fmin, 4fmin and 8fmin