Enhancement of the antenna bandwidth by coupling the planar inverted-F antenna and multi-ultra-thin slots for handheld devices with metal housing

摘要

We propose an invisible multi-ultra-thin slot antenna and a planar inverted-F antenna (PIFA) coupling design for handheld mobile devices in complete metal housing systems. To enhance the bandwidth of the traditional single /4 PIFA used in a 2.45-GHz Wi-Fi system and to consider the strong impact on radiation due to the metal-housing shielding effect and position of the internal antenna, this design etches 0.1-mm wide slots on the metal housing using PIFA to excite these slot antennas through coupling. The metal housing is a major radiator that enhances the antenna bandwidth and efficiency. It uses electric and magnetic coupling between the two antennas to achieve the specification bandwidth, and we design the number, gap, and position of slots by investigating the mutual coupling effect. The bandwidth of the proposed structure is 147 and 134MHz in simulations and in measurements involving the etching of three multi-ultra-thin slots, respectively (L=38mm, W=0.1 mm), for 2.45-GHz usage. The results depict that this design enhances the antenna bandwidth when some slots are etched, especially for handheld devices with metal housing.