Diversity antennas for isotropic coverage

Three-element polarization / pattern diversity antennas for isotropic coverage (covering all directions and any linear polarization) are presented for frequencies around 1.5 GHz. Based on perpendicularly mounted, co-centred dipoles, a broadband (VSWR <; 1.5 over 15% bandwidth) and compact (kr = 0.9 at the lower frequency band edge) design is possible. Radiation pattern and gain are similar to those of a half-wavelength dipole. These antennas can find application as orientation-insensitive tags in sensor networks.