Dual-Band Microstrip Patch Antenna with the Profile of 0.5 mm Covering 3.4~3.6 GHz and 4.8~4.96 GHz for 5G Mobile Terminal Applications

The antennas on the metal bezel for the mobile terminal devices are so crowded that the engineers must find another space such as the screen or the back cover to accommodate all kinds of antennas with diverse functions. This article proposes a novel method to develop a dual-band planar antenna with an extremely low profile of 0.5 mm on the back cover. The first two characteristic modes TM<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,0</inf> and TM<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5,1</inf> of the half-mode patch antenna are used to cover the lower band of partial 5G band N78 (3.40~3.60 GHz) and higher band of 5G band N79 (4.80~4.96 GHz). A back-to-back topology of magnetic coupling introduces a parasitic half-mode patch to produce an additional resonance for bandwidth enhancement of each band. The simulated results show that the -6 dB impedance bandwidths are 3.39~3.67 GHz (280 MHz, 7.9%) and 4.80~4.99 GHz (190 MHz, 3.9%) with average total efficiencies of -2.3 dB (58.9%) and -3.3 dB (46.7%) at the lower and higher bands respectively. The proposed antenna is with an extremely low profile of 0.5 mm, about 0.006 λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</inf> (λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</inf> refers to the lowest frequency of the operation band), which has a great potential to be applied in mobile terminal devices.