Antennas for use in portable communications devices

摘要: Antenna arrangements for use with portable communications devices are described. In one embodiment, an antenna (50) has four equally spaced monopole elements (52-58) mounted in a regular array on the outer surface of solid cylinder structure (60). The cylindre (60) high dielectric constant, and extends from conductive ground plane (62). can be switched by switching (64-70, 76) so that or more is active, others acting as parasitic directors/reflectors being connected commonly to left open circuit condition effectively transparent. A shielded single (10) also