Hybrid of monopole and dipole antennas for concurrent 2.4‐ and 5‐GHz WLAN access point

A novel hybrid of a 2.4‐GHz monopole antenna and a 5‐GHz dipole antenna is presented to provide concurrent 2.4 and 5 GHz band operation for access‐point applications. The two antennas are arranged in a collinear structure and printed on a compact dielectric substrate with dimensions 12 mm × 60 mm. The monopole antenna has a meandered radiating strip and is short‐circuited to a small ground plane through a shorting strip. The dipole antenna includes two sub‐dipoles at the opposite side of a narrow ground plane and fed by a simple T‐junction microstrip‐line network. The two antennas are closely set with a distance of 1 mm only, yet good port isolation (S 21 ) well below −20 dB can be obtained. With a low profile, the proposed design can easily fit into the casing of some standard access points and allow the 2.4 and 5 GHz band signals to be simultaneously received or transmitted with no external diplexer required. Good omnidirectional radiation has been observed too.