An ultra‐wideband multiple‐input multiple‐output antenna with dual band‐notched characteristics

Abstract

In this paper, an ultra-wideband multiple-input multiple-output antenna with dual band-notched characteristics is proposed. The radiating element is an octagonal structure using a tapered microstrip line to feed. A multimode resonator is introduced on one side of the microstrip feed line to achieve dual band-notched characteristics, which eliminates the interference of wireless local area network band and X satellite communication frequency band. By using a diamond-shaped defect ground structure and extending a parasitic branch at the centre axis of the ground, the mutual coupling of the antenna is reduced to À20 dB. The proposed antenna has a compact size of 30 Â 35 Â 0.8 mm 3 . The measured results are in good agreement with the simulation results. The proposed antenna covers 3.1-10.6 GHz with dual notched-band characteristics and the mutual coupling below À20 dB. The antenna has a good diversity performance as the envelope correlation coefficient <0.03. The antenna is suitable for ultra-wideband communications. K E Y W O R D Smultiple-input multiple-output (MIMO), notch band, ultra-wideband (UWB) | INTRODUCTIONUltra-wideband (UWB) technology has been widely used because of its high transmission rate, high security, and low power consumption, since the Federal Communications Commission (FCC) approved 3.1-10.6 GHz for low-power transmission in 2002. 1 However, UWB technology also faces problems like multi-path fading, and due to the limitation of power density, UWB technology is only used for shortrange communications. The combination of UWB system and multiple-input multiple-output (MIMO) technique can not only improve the multi-path fading, but also greatly increase channel capacity, signal transmission rate and improve communication quality. 2 In addition, there are many narrow bands that have been put into use in the operating frequency band of UWB technology, like the worldwide interoperability for microwave access (WiMAX), wireless local area network (WLAN) and the X satellite communication frequency band. In order to eliminate