Reconfigurable multi-port antennas for handheld devices

Multiple-input multiple-output (MIMO) technology is a technique which can increase capacity by exploiting multiple antennas in transceivers without the need for extra spectrum or transmit power. This technique is expected to be employed in handheld devices as high bit rate intensive applications become more popular, such as internet access, high definition signal transmission or on-line gaming. However, a major challenge for integrating a multiple-antenna system in a handheld device is the arrangement of the antennas, as they cannot be placed anywhere without considering the coupling effect between elements. However the volume of the handheld is strictly limited and therefore fundamental limits restrict what operating configurations of bandwidth, frequency and number of ports that can be achieved. One way forward is to consider reconfigurable antennas that can reuse the existing volume and electronically reconfigure the multi-element antennas to different frequency bands and various multi-port antennas at different times. This paper presents two implementations which can reconfigure the multi-port antennas to operate in lower frequency bands. The first approach uses an additional slot on the ground plane to allow reconfiguration and the second approach is by connecting two short radiating elements together to form a longer current path.