Internal Coupled-Fed Dual-Loop Antenna Integrated With a USB Connector for WWAN/LTE Mobile Handset

Abstract

A coupled-fed dual-loop antenna capable of providing eight-band WWAN/LTE operation and suitable to integrate with a USB connector in the mobile handset is presented. The antenna integrates with a protruded ground, which is extended from the main ground plane of the mobile handset to accommodate a USB connector functioning as a data port of the handset. To consider the presence of the integrated protruded ground, the antenna uses two separate shorted strips and a T-shape monopole encircled therein as a coupling feed and a radiator as well. The shorted strips are short-circuited through a common shorting strip to the protruded ground and coupled-fed by the T-shape monopole to generate two separate quarter-wavelength loop resonant modes to form a wide lower band to cover the LTE700/GSM850/900 operation (704-960 MHz). An additional higher-order loop resonant mode is also generated to combine with two wideband resonant modes contributed by the T-shape monopole to form a very wide upper band of larger than 1 GHz to cover the GSM1800/1900/UMTS/LTE2300/2500 operation (1710-2690 MHz). Details of the proposed antenna are presented. For the SAR (specific absorption rate) requirement in practical mobile handsets to meet the limit of 1.6 W/kg for 1-g human tissue, the SAR values of the antenna are also analyzed.Index Terms-Coupled-fed loop antennas, handset antennas, LTE antennas, mobile antennas, USB connector, WWAN antennas.

Antenna Booster Element for Multiband Operation

“…Note that the present antenna booster element can be integrated into such narrow devices due to the short length of only 30 mm [42]. At HFR, efficiency is only better for [8], which again includes a large antenna of 55 mm and a height of 8 mm. For the other antennas, the antenna booster element presents better efficiency, a smaller size, and a lower height.…”

“…Regarding total efficiency, the proposed solution is only smaller compared to [8] and [9] for LFR at the expense of a much larger antenna size. For example, the antenna length in [8] is 80 mm, which is difficult to integrate into IoT devices featuring widths less than 60 mm.…”

“…Regarding total efficiency, the proposed solution is only smaller compared to [8] and [9] for LFR at the expense of a much larger antenna size. For example, the antenna length in [8] is 80 mm, which is difficult to integrate into IoT devices featuring widths less than 60 mm. The same occurs with [9]; the antenna length is 55 mm, which makes it prohibitive for devices featuring a width of less than 50 mm, in addition to its height of 8 mm compared to only 1 mm for the antenna booster element.…”

“…While traditional single-band antennas suffice for conventional equipment, contemporary systems demand more versatile and efficient solutions, such as dual-band or multiband antennas [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], to accommodate operations across multiple frequencies. Moreover, compact antenna form factors are crucial, considering the diverse sizes and internal electronics of these devices.…”

Small Size Coupling Feed and Inductive Shorting Antenna for Wide Bandwidth, Increased Gain and Efficiency With Low Specific Absorption Rate (Sar) Operation

“…In this modern era of cell phone miniaturization, mobile phones with their compact size and their multi-band operation capabilities are in a great demand providing researchers greater interest in antenna designs. These demands of multi-band operation, miniaturization, high efficiency, being lightweight and low specific absorption rate (SAR) inspire researchers to investigate efficient antennas for mobile communication systems [1][2][3][4][5].…”