Self‐decoupled compact metal‐frame LTE MIMO antennas for the smartphone

Abstract

Two self‐decoupled, closely‐spaced, metal‐frame LTE MIMO antennas with compact frame lengths to fit in the short edge of the metal‐framed smartphone are presented. The 2 MIMO antennas include a first antenna covering the LTE low band (LB) in 824–960 MHz and LTE middle/high band (M/HB) in 1710–2690 MHz and a second antenna covering the LTE M/HB in 1710–2690 MHz. With a small ground clearance of 5 mm, the first antenna uses a radiating metal frame (frame 1) of length 47 mm to cover the LTE L/M/HB, while the second antenna uses a radiating metal frame (frame 2) of 23.4 mm for the LTE M/HB coverage. In addition, frames 1 and 2 are closely spaced with a gap of 2 mm only. Wideband decoupling between the 2 antennas for the 2 × 2 MIMO operation in the LTE M/HB is obtained with frame 2 serving as an inherent decoupling structure. That is, frame 2 not only functions as a radiator of the second antenna but also serves as a decoupling structure to attract the surface currents on the system ground plane which causes the coupling of the 2 antennas. Applications of applying another 2 MIMO antennas at the opposite short edge of the smartphone for the 4 × 4 LTE M/HB and 2 × 2 LTE LB MIMO operations are also addressed.

Co-Designed Handset Antennas with Wide Angular mm-Wave Coverage and LTE MIMO

“…When the diversity antenna is added, the efficiency of the main antenna drops roughly 20 percentage points at the low band compared to [13]. Comparison to other published designs [5], [6], [15] shows that both configurations perform well among them. Benefit of this design is the passive implementation that enables carrier aggregation, whereas, e.g., [5], [6] present reconfigurable designs.…”

One LTE LB and two conjoined LTE M/HB MIMO antennas with a compact symmetric frame structure at the short edge of the metal‐framed smartphone

“…The reported metal‐frame antennas that include at least two LTE antennas to provide two LTE L/M/HBs or one LTE LB and two LTE M/HBs for multi‐input multi‐output (MIMO) operation are relatively very few . In Ref.…”

“…For modern slim smartphones, the metal-frame structure around the edges of the smartphone has become very popular to achieve robustness thereof. 1,2 For such metal-framed smartphones, the long-term evolution (LTE) antennas integrated with the metal-frame structure to operate as loop antennas [3][4][5][6][7] or inverted-F antennas (IFAs) [8][9][10][11][12] or open-slot antennas 12,13 have also been reported. It is noted that many of the reported metal-frame LTE antennas can cover one LTE low band (LB) and one LTE middle/high band (M/HB) only.…”

“…3,[5][6][7][8][9][10] The reported metal-frame antennas that include at least two LTE antennas to provide two LTE L/M/HBs or one LTE LB and two LTE M/HBs for multi-input multi-output (MIMO) operation are relatively very few. 4,[11][12][13] In Ref. 4 , each LTE antenna, however, requires a metal-frame section much longer than the short edge of the smartphone.…”

Printed eight‐band compact antenna with lumped inductance for wireless USB dongle

“…Mobile terminal antennas, as components of the system, have received great attention as well. Some mobile terminal antenna designs have been reported in literatures, such as compact mobile terminal antenna, self‐decoupled compact smartphone antenna, and compact 4‐element 5G MIMO antenna . USB dongles, as important parts of the mobile terminal, are convenient for people to access Internet.…”