Closely-Packed UWB MIMO/Diversity Antenna With Different Patterns and Polarizations for USB Dongle Applications

Abstract

A closely-packed ultrawideband (UWB) multipleinput multiple-output (MIMO)/diversity antenna (of two elements) with a size of 25 mm by 40 mm is proposed for USB dongle applications. Wideband isolation can be achieved through the different patterns and polarizations of the two antenna elements. Moreover, the slot that is formed between the monopole and the ground plane of the half slot antenna is conveniently used to further enhance the isolation at the lower frequencies and to provide an additional resonance at one antenna element in order to increase its bandwidth. The underlying mechanisms of the antenna's wide impedance bandwidth and low mutual coupling are analyzed in detail. Based on the measurement results, the proposed antenna can cover the lower UWB band of 3.1-5.15 GHz, and within the required band, the isolation exceeds 26 dB. The gains and total efficiencies of the two antenna elements are also measured. Furthermore, a chassis mode can be excited when a physical connection is required between the ground planes of the two antenna elements. Without affecting the performance of the half slot element, the monopole can now cover the band of 1.78-3 GHz, apart from the UWB band. The proposed antenna structure is found to provide good MIMO/diversity performance, with very low envelope correlation of less than 0.1 across the UWB band.Index Terms-Multiple-input multiple-output (MIMO), mutual coupling, pattern diversity, polarization diversity, ultrawideband (UWB) antenna.

A Compact Band-Notched Ultra-Wideband Spatial Diversity Antenna

“…Many studies have been carried out to design UWB diversity antennas [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, the impedance bandwidth of the antennas in [5][6][7][8] cannot cover the whole UWB, and the sizes of the antennas are relatively large in [5,[9][10][11][12][13][14][15][16][17] which are not suitable for some portable devices' applications.…”

“…However, the impedance bandwidth of the antennas in [5][6][7][8] cannot cover the whole UWB, and the sizes of the antennas are relatively large in [5,[9][10][11][12][13][14][15][16][17] which are not suitable for some portable devices' applications. On the other hand, the frequency range for UWB systems between 3.1 to 10.6 GHz will cause interference to the existing wireless communication systems, such as the wireless local area network (WLAN) for IEEE 802.11a operating in 5.15-5.825 GHz, so the UWB diversity antenna with a band-notched function is desired in the design.…”

“…On the other hand, the frequency range for UWB systems between 3.1 to 10.6 GHz will cause interference to the existing wireless communication systems, such as the wireless local area network (WLAN) for IEEE 802.11a operating in 5.15-5.825 GHz, so the UWB diversity antenna with a band-notched function is desired in the design. However, the antennas in [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] do not have the band-notched function to avoid the interference. Recently, some antennas with band-notched function have been reported [22][23][24][25][26][27].…”

Mimo Reference Antennas With Controllable Correlations and Total Efficiencies

“…In fact, this decoupling mode is introduced by the slot. This decoupling slot mode has been studied in [12,13]. In this paper, by adjusting the length of the slot, a proper amount of the decoupling mode will be introduced to control the ECC levels.…”

Triple Band Notched Dg-Cebg Structure Based Uwb Mimo/Diversity Antenna

“…Different techniques are used to decrease mutual coupling between antenna elements, such as novel antenna designs [28,29], using slots in the ground plane [30][31][32] and use of EBG patches [33,34]. The designs in [35][36][37] are not capable of functioning over the complete band unrestricted by FCC.…”