Low-profile omnidirectional dual-polarised antenna for 2.4 GHz WLAN applications

A low-profile omnidirectional dual-polarised antenna for 2.4 GHz wireless local area network (WLAN) applications is proposed. The vertically/horizontally dual-polarised radiation patterns are achieved by combining a modified monopole antenna with a printed arc dipole array. The overall volume of the presented antenna is less than 0.63λ₀ × 0.63λ₀ × 0.057λ₀ (λ₀ is the free-space wavelength at central frequency). To verify the design, a prototype antenna is fabricated and tested. The measured results show that the -10 dB impedance bandwidths for vertical polarisation (VP) and horizontal polarisation (HP) have both covered the required band of 2.4-2.48 GHz and the isolation, in the operating band, is more than 24 dB. The measured cross-polarisation levels within the working plane for VP and HP are lower than -18 dB. Stable antenna gains are greater than 0.46 and 0.44 dBi for VP and HP over the operating frequency band, respectively.