Integrated yet decoupled dual antennas with inherent decoupling structures for 2.4/5.2/5.8-GHz WLAN MIMO operation in the smartphone

Abstract

Integrated yet decoupled (IYD) dual antennas with inherent decoupling structures to achieve multi-input multioutput operation in the 2.4/5.2/5.8-GHz wireless local area network bands in the smartphone are presented. The IYD dual antennas consist of two coupled-fed loop antennas integrated into a compact planar structure of size 7 3 25 mm 2 . Each coupled-fed loop antenna has a longer coupled-fed end-shorted strip for the 2.4-GHz band (2400-2484 MHz) and a shorter coupled-fed end-shorted strip for the 5.2/5.8-GHz bands (5150-5350/5725-5875 MHz). The decoupling between the two antennas is obtained by the longer end-shorted strips thereof as inherent decoupling structures. No external decoupling structures are required. This decreases the antenna size and simplifies the structure of the IYD dual antennas. For the smartphone application, the IYD dual antennas are disposed along the side-edge frame thereof and placed perpendicular to and also centered to the system ground plane therein with a 1-mm ground clearance only. Details of the proposed IYD antennas are presented and discussed. K E Y W O R D S inherent decoupling structures, integrated yet decoupled dual antennas, MIMO antennas, mobile antennas, WLAN antennas AbstractAs a conventional branch line coupler (BLC) is limited to a phase difference of 908, different phases have typically QAMAR ET AL. | 2241

Dual‐band dual inverted‐F/loop antennas as a compact decoupled building block for forming eight 3.5/5.8‐GHz MIMO antennas in the future smartphone

“…That is, the occupied length along the side edge of the smartphone is 15 mm or about 0.175 wavelength at 3.5 GHz. The occupied length with respect to the operating wavelength is decreased, as compared to that in Ref . This advantage is obtained not only because there are no external decoupling structures required, but also because there is no lateral spacing required between the two dual‐band antennas to achieve good decoupling there between in two different operating bands.…”

“…Recently, this challenging task has attracted great attention. Eight or sixteen MIMO antennas embedded in the smartphone for the MIMO operation have been reported . However, most of the reported MIMO antennas are for single‐band operation only, which are not suitable for MIMO operations in the heterogeneous networks, such as the mobile network and the wireless wide area network (WLAN).…”

“…However, most of the reported MIMO antennas are for single‐band operation only, which are not suitable for MIMO operations in the heterogeneous networks, such as the mobile network and the wireless wide area network (WLAN). In Ref., integrated yet decoupled loop antennas for the 2.4/5.2/5.8‐GHz WLAN operation have been reported. There are two dual loop antennas closely integrated to have a compact planar size of 7 × 25 mm 2 along the side edge of the smartphone.…”

Decoupled compact ultra‐wideband MIMO antennas covering 3300∼6000 MHz for the fifth‐generation mobile and 5GHz‐WLAN operations in the future smartphone

“…The expected 3300$6000 MHz spectrum will include 3300$5000 MHz for the fifth-generation mobile multi-input multi-output (MIMO) operation [6][7][8][9][10][11] and 5150$5875 MHz for wireless wide area network (WLAN) MIMO operation. [12][13][14] Note that when the MIMO operation is operated with as many smartphone antennas as possible, high-speed data throughput much higher than the current fourth-generation (4G) communications can be obtained, 3 which will be demanded for the fifthgeneration or future mobile communications.…”

“…However, it is noted that the available MIMO antennas reported for the smartphone application are not capable of covering the UWB of 3300$6000 MHz. [6][7][8][9][10][11][12][13][14] This is owing to the very limited space available inside the smartphone, which makes the UWB MIMO antennas to have compact size and low correlation a great design challenge. This motivates the present study to develop decoupled compact UWB MIMO antennas to cover 3300$6000 MHz for the fifthgeneration mobile and 5GHz-WLAN operations in the future smartphone.…”