An omni-directional multi-polarization and multi-frequency antenna

In this paper a single layer planar antenna, which simultaneously radiates circularly polarized waves and linearly polarized waves at two different frequencies for the mobile phone and ISM bands, is presented. Software simulations of the proposed design and associated measurements are reported as well. The presented antenna has the following features: (a) it is a single-layer electrically small planar antenna, (b) it radiates circularly polarized waves and linearly polarized waves simultaneously by means of a single feeding port without the need of a phase shifter, (c) it is omni-directional. The antenna design shown in this paper can be easily applied to single layer printed boards, which makes the antenna very suitable for mobile phone and RFID applications.