A Compact Dual Polarisation Antenna with Improved Impedance Matching and Reduced Cross Polarisation

The built antenna resonates 5.9 GHz with peak gain 6.85 dBi in this configuration; a dual polarization microstrip patch antenna is achieved. It is necessary to cause a 90-degree phase delay between the components of the electric and magnetic field in order to provide circular polarization, to achieve right hand polarisation, to add a slot at the edge of the radiating patch and to achieve left hand polarisation in the cut of the ground corner. Both polarisations have an axial ratio of 1. Parallel slots and arc shaped slots are introduced as defected ground structure to improve impedance matching and reduce cross polarisation respectively. The antenna is manufactured and tested and it offers reasonable agreement between the effects of the simulation and measurement. This antenna is ideal for interacting with vehicles.