A Reconfigurable Metal Rim Antenna With Smallest Clearance for Smartphone Applications

Abstract

In this paper, a reconfigurable metal rim antenna with a small clearance and compact structure for 4G/5G smartphones is proposed. It consists of the system ground plane and a metal rim with two slits, in which a U-shaped slot of 1 mm (the smallest) clearance is realized between the system ground and metal rim. The theory of characteristic modes is applied to analyze the eigenmodes of the antenna so as to aid the optimum design. The characteristic modes (CMs) in the band of interest are studied, and an inductive coupling exciter is identified as the best since three CMs can therefore be generated in the lower frequency band (0.69-0.96 GHz), and an SP4T switch can be utilized to increase the bandwidth of the whole lower band. A prototype antenna of the optimized design was fabricated. A good agreement was obtained between the measured and simulated results. The 6-dB frequency bands are the lower band (0.69-0.96 GHz), the middle band (1.7-2.7 GHz), and the higher 5G band (3.4-3.6 GHz), respectively, and the total efficiencies are over 50% in all these frequency bands. They indicate that the antenna is a very good candidate for smartphone applications.INDEX TERMS Metal rim antenna, mobile antenna, reconfigurable antenna, small ground clearance, theory of characteristic modes.

Reconfigurable Antenna Booster System for Multiband Operation in IoT Devices With an SP4T Switch

“…However, in the present case, efficiency in the low-frequency region (698 MHz -960 MHz) is 3.7 dB above, plus the simplicity of using only one SP4T switch. In contrast, the compared devices [23], [24], [30] and [32] feature a larger ground plane in dimensions (0.35, 0.32, 0.47 and 0.30) than the current solution (0.16), which implies a higher efficiency in the lower frequency bands. Moreover, [23] and [24] incorporate a metal frame, which is not viable for IoT devices due to cost.…”

“…In contrast, the compared devices [23], [24], [30] and [32] feature a larger ground plane in dimensions (0.35, 0.32, 0.47 and 0.30) than the current solution (0.16), which implies a higher efficiency in the lower frequency bands. Moreover, [23] and [24] incorporate a metal frame, which is not viable for IoT devices due to cost. The innovative aspect of the proposed solution lies in its utilization of a single switch, with a more compact volume antenna booster, whereas [24] stands out for having the smallest clearance area despite incorporating a metal frame.…”

“…Moreover, [23] and [24] incorporate a metal frame, which is not viable for IoT devices due to cost. The innovative aspect of the proposed solution lies in its utilization of a single switch, with a more compact volume antenna booster, whereas [24] stands out for having the smallest clearance area despite incorporating a metal frame. As observed, the antenna volume is only 90mm 3 , which is less than the metal frame structures in [23] and [24] and 26 times less than the antennas in [30] and [32].…”

“…In [24], a U-shape slot of 1mm wide is designed in a PCB of 143x74 mm 2 without clearance area and connected to an SP4T switch, four states, that is grounded. It uses eight lumped components, and the frequency ranges are 690 -960 MHz and 1700 -2700 MHz.…”

Antennas for Licensed Shared Access in 5G Communications with LTE Mid- and High-Band Coverage

“…Some antennas have been reported to cover both the 1710–2690 MHz (LTE mid) and 3400–3800 MHz (LTE high) frequency ranges [ 22 , 23 , 24 , 25 , 26 ]. Recently, an antenna was presented in [ 27 ] that covers both frequency bands. However, in order to achieve acceptable impedance matching ( dB) in the above-mentioned bands, an extra lumped-element-based circuit is required with the feed section.…”