Summary

International Symposium on Antennas and Propagation

2010

Session Number:3TA1

Session:

Number:3TA1-2

A Closely-Packed MIMO Antenna for USB Dongle Application at WLAN Band

Wenhui Huang,  Minseok Han,  Jaehoon Choi,  

pp.-

Publication Date:2010/11/23

Online ISSN:2188-5079

DOI:10.34385/proc.52.3TA1-2

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Summary:
A MIMO(Multiple Input Multiple Output) antenna system is a technique to improve the performance of wireless communication systems. In order to design a MIMO antenna system for USB(Universal Serial BUS) dongle application , two or more antenna elements are required to dispose within a small space. Due to the sophisticated and small structure of a USB dongle, the space allowed for antenna is extremely limited. So far, many researchers have been trying to find new techniques for isolation improvement between antenna elements. Mushroom-like EBG structures can suppress the surface wave between antenna elements so that the mutual coupling between antenna elements is reduced[1]. However, mushroom-like structure occupies a huge area. A compact integrated diversity antenna with two feed ports has been introduced[2]. However, the antenna element is too large to be used for USB dongle application. In [3], the mutual coupling is reduced by etching multiple slots on the ground plane to realize a LC band-stop filter. However, such antenna design cannot be utilized for a USB dongle with other electronic units, meanwhile a large ground plane size is needed for sufficient isolation. In [4], the method using lumped circuit networks on the input ports is proposed to decouple two closely spaced PIFAs. However, this technique requires implementations of several capacitors, inductors and significantly increases the cost and complexities. In [5], an additional folded resonator with electrical length of about half a guided wavelength is placed above the two PIFAs, but the return loss achieved is only 12 dB at the desired band. In [6], a metamaterial directional coupler is introduced to improve the isolation. However, the bandwidth is very narrow. In this paper, a compact MIMO antenna for USB dongle application at WLAN band is proposed. The proposed MIMO antenna consists of two identical meander line antennas connected through a common metallic strip. To improve the isolation performance, suspended lines were inserted between the two antenna elements. The suspended line acts as a band stop filter and provides a good isolation between the two ports despite of very close distance. The measured isolation characteristics between the two antenna elements is higher than 18 dB.