Low-Profile Wideband Patch Antenna Using Even and Odd Modes for 5G Terminal Applications

This letter presents a low-profile wideband microstrip patch antenna (MPA) based on even and odd modes and its four-antenna module on a 5G terminal back cover. Two pairs of even and odd resonance modes, i.e., TM
_3/2,0
, anti-TM
_3/2,0
, TM
_0,3/2
and anti-TM
_0,3/2
modes, each with independent tuning capability, are excited and combined for the first time to cover a wide impedance bandwidth. The proposed antenna with a low profile of 1 mm (0.01λ
_L
) shows the −6 dB impedance bandwidth spans from 3.4 GHz to 4.2 GHz (21.1%). Then, a four-element multiple-input–multiple-output (MIMO) antenna module is configured on the typical back cover of a mobile terminal in a sequentially rotated layout. To improve the isolation further, four neutralization lines are utilized between the adjacent elements. To validate the concept, the proposed MIMO antenna module was fabricated and tested. Over 21 dB isolation can be achieved across (3.4 to 4.3) GHz with an edge-to-edge distance of 3 mm. This MPA module provides a promising solution to design a low-profile planar antenna for terminal devices with a wide impedance bandwidth.