Investigation and design of enhanced decoupled UWB MIMO antenna for wearable applications

Abstract

A lightweight multi‐input multi‐output (MIMO) two‐element wearable ultra‐wideband (UWB) antenna having a port isolation of greater than 21 dB is introduced in this communication. The proposed structure includes wearable jeans cloth as a substrate, wherein two inverted u‐formed stubs are mounted in the middle position located on the backside of antenna and attached to the partially etched ground for enhancing the characteristics of port isolation. The developed UWB MIMO antenna has a size of 50 x 35 mm2 and covers the frequency range operating from 1.83 to 13.82 GHz (~153.2%). The suggested MIMO antenna is inexpensive and functions across a broad frequency range of applications including WLAN (2.4‐2.484 GHz/5.15‐5.35 GHz/5.72‐5.825 GHz), Downlink‐uplink WiMAX (3.2‐3.85 GHz), and C‐band (3.7‐4.2 GHz/5.925‐6.425 GHz). The diversity gain (DG) is found to be greater than 9.9 along with envelope correlation coefficient (ECC) to be less than 0.059 across the entire operating bandwidth. The proposed MIMO antenna's channel power loss is bestowed to be less than 0.35 bit/s/Hz. The SAR results of the proposed UWB MIMO design admits that the antenna performs satisfactorily and is suitable for wearable applications. Simulation and testing fairly proved the output of the proposed antenna as a righteous candidate applicable for UWB MIMO applications.

Super‐UWB MIMO antenna with high isolation

“…(D) shows the S11 versus frequency of the Super‐UWB MIMO antenna with respect to different length sizes of the ground plane. It can be found that the ground plane size influencing the impedance match, which is common case for UWB antennas 2,26–29 . In this design, length of the ground plane (Lg) of 11 mm has a good impedance match with S11 below −10 dB in the entire band of operation.…”

Periodically-Stub-Loaded Microstrip Line Wideband Circularly Polarized Millimeter Wave MIMO Antenna

“…The lowest correlation corresponds to the better MIMO performance. The ECC in far-field for a multi-antenna model is expressed as [17]:…”

“…The required value of the DG for the MIMO system should be around 10dB. The DG is a function of ECC and can be expressed as [17]:…”

Design and analysis of a CPW ‐fed flexible ultrawideband antenna for microwave imaging of breast cancer

“…These contours are assumed to be distributed and represents the power concentration on the phantom model whenever the antenna emits an UWB signal into the phantom. The assessment of SAR values with standard distances available in the literature 12,14,20 are addressed in Table 6. Figure 22 demonstrates that the SAR values on the phantom model for 1 g of body tissue are 0.215, 0.463, 0.710 and 0.930 W/Kg (less than 1.6 W/Kg for 1 g tissue) at frequencies of 3.5, 5.8, 8.4 and 10.6 GHz which makes the suggested antenna totally safe for exposure in humans and ideal for MWI biomedical applications 24,56 …”

“…Nevertheless, they are the most appropriate and compatible antennas for MI of tumor tissues, but tradeoff exists due to limited bandwidth and big-size of the design. Although such antennas have an intrinsic limitation with the narrow bandwidth 4,9 so researchers use different kinds of feeding techniques, 10 such as offset fed patch antennas, 11 introduction of slots on patches, 12 using low-dielectric substrates, 13,14 increasing the thickness of a substrate 15 and so forth. to obtain large operating bandwidth, but with these methods, several performance characteristics degrades.…”