This paper presents a metamaterial-based flexible wearable ultra-wideband (UWB) antenna for breast imaging and wireless body area network (WBAN) applications. The wearable antenna is required to be a planar and low-profile structure using flexible materials. The proposed antenna comprises two layers of denim (10 × 10 mm²) and felt (10 × 15 mm²). The antenna was integrated with six metamaterial unit cells using a modified grain rice shape within a split ring resonator to enhance the bandwidth, gain, and directivity and reduce the specific absorption rate value to less than 2 W/kg. The proposed antenna operates within a broad bandwidth range (6.5 GHz–35 GHz) with the maximum gain and directivity of 8.85 dBi and 10 dBi, respectively, and a radiation efficiency of more than 70% over its operating frequency band. The results verified good agreement between the simulation and measurement of the proposed technique in detecting an existing tumor with a diameter of 4 mm from any location inside the breast. The results convincingly proved the capability of the proposed wearable UWB antenna system for both WBAN and breast imaging applications.

A low-profile Multiple Input Multiple Output (MIMO) antenna showing dual polarization, low mutual coupling, and acceptable diversity gain is presented by this paper. The antenna introduces the requirements of fifth generation (5G) and the satellite communications. A horizontally (4.8–31 GHz) and vertically polarized (7.6–37 GHz) modified antipodal Vivaldi antennas are simulated, fabricated, and integrated, and then their characteristics are examined. An ultra-wideband (UWB) at working bandwidths of 3.7–3.85 GHz and 5–40 GHz are achieved. Low mutual coupling of less than −22 dB is achieved after loading the antenna with cross-curves, staircase meander line, and integration of the metamaterial elements. The antennas are designed on a denim textile substrate with ${\epsilon }_r$ = 1.4 and h = 0.5 mm. A conductive textile called ShieldIt is utilized as conductor with conductivity of 1.8 × 10⁴. After optimizing the proposed UWB-MIMO antenna’s characteristics, it is increased to four elements positioned at the four corners of a denim textile substrate to be employed as a UWB-MIMO antenna for handset communications, 5G, Ka and Ku band, and satellite communications (X-band). The proposed eight port UWB-MIMO antenna has a maximum gain of 10.7 dBi, 98% radiation efficiency, less than 0.01 ECC, and acceptable diversity gain. Afterwards, the eight-ports antenna performance is examined on a simulated real voxel hand and chest. Then, it is evaluated and compared on physical hand and chest of body. Evidently, the simulated and measured results show good agreement between them. The proposed UWB-MIMO antenna offers a compact and flexible design, which is suitably wearable for 5G and satellite communications applications.

Trapping parameters can be considered as one of the important attributes to describe polymeric materials. In the present paper, a more accurate charge dynamics model has been developed, which takes account of charge dynamics in both volts-on and off stage into simulation. By fitting with measured charge data with the highest R-square value, trapping parameters together with injection barrier of both normal and aged low-density polyethylene samples were estimated using the improved model. The results show that, after long-term ageing process, the injection barriers of both electrons and holes is lowered, overall trap depth is shallower, and trap density becomes much greater. Additionally, the changes in parameters for electrons are more sensitive than those of holes after ageing.