This paper presents a novel wearable antenna sensor based on localized surface plasmons (LSPs) for communication and non-invasive sweat monitoring. The sensor is made up of corrugated plasmonic structures based on the conventional printed monopole antenna, which achieves multi-band and miniaturization. The physical dimensions of the antenna sensor are 35 × 34 mm ² , with a thickness of only 0.13 mm. Simulated and measured results demonstrate that the proposed antenna sensor covers triple operating bands, including 2.4 GHz and 5.8 GHz ISM bands, as well as high frequency ultra-wideband ranging from 7.89 GHz to 9.56 GHz. The antenna sensor exhibits a good radiation pattern with a peak gain of 3.02 dBi and a high quality factor (Q) up to 35. The use of polyimide as a dielectric substrate enables the antenna sensor to achieve flexibility and conformality, maintaining stable operating states even when bent and deformed. The specific absorption rate (SAR) values in three frequency bands are simulated and evaluated to ensure its safety for human health. Moreover, the resonant frequency of antenna sensor significantly shifts with the volume and concentration of sweat, indicating that the proposed sensor is highly sensitive to sweat volume and concentration with a sensitivity of 120 MHz/1mm and 4.57 MHz/1, respectively. The proposed wearable antenna sensor is a promising candidate for a sweat monitoring system for athletes or patients, allowing for health monitoring at any time and place.

Electromagnetic radiation from transmission lines is an important topic in electromagnetic compatibility. Thus, this paper aims at developing an analytical technique to evaluate radiated electric field and shielding effectiveness (SE) of shielded cable. The induced voltages and currents on the screen are modeled by the surface transfer impedance with Kley's method. Then, based on the Hertzian dipole technique, the radiating transmission line is decomposed into small-length hypothetical dipoles and the total electromagnetic radiation can be replaced by the summation of the dipoles. After that, the SE expression of shielded cable is obtained according to the electromagnetic calculation results, which is defined by using transfer impedance. Finally, numerical simulations are carried out by using a commercial software computer simulation technology (CST) to validate the proposed approach. The expressions give a way of allowing fast parametric analysis of radiation and SE during the design phase of the electrical and geometrical configuration of shielded cable.

This work proposes an element with 1-bit phase resolution that operates in both reflection and radiation modes. The 1-bit phase responses in two operating modes can be realized by switching the states of three integrated PIN diodes. The array composed of the elements can be excited as both a reflectarray (RA) by the external feed in space and a phased array (PA) without phase shifters by the integrated feeding network at its bottom. Drawing inspiration from the RA, the feeding network introduces initial phase distributions irradiated by a hypothetical spatial feed above the PA to mitigate the grating lobes of the 1-bit PA. An electronically reconfigurable array antenna prototype composed of 8 × 16 elements was manufactured and measured to verify its performance. The experimental results indicate that the designed array antenna can realize dynamic beam scanning in the range of ±45° in E-plane and ±30° in H-plane within less than 3 dB gain loss, verifying its feasibility for both RA and PA applications.

In this communication, a novel hybrid decoupler is proposed to reduce mutual coupling for an extremely compact wideband stacked patch MIMO array antenna. The hybrid decoupler consists of a dielectric surface and a metasurface. By using a well-designed dielectric surface, the mode of mutual coupling current on the unexcited antenna can become orthogonal to its polarization mode. Moreover, the electrical distance of coupling wave propagation between two elements is prolonged. Antenna decoupling is naturally achieved. Then, the metasurface, which can reject coupling wave propagation, is a complementary method to further improve isolation. Dielectric rod array is designed by partially hollowing the dielectric surface, which can realize optimized dielectric constant of slab and better combine two decoupling methods. A broadband stacked patch array antenna is chosen as a demonstration to prove that this idea can achieve wide isolation improved bandwidth, as well as high isolation improved degree. Measured results reveal that isolation enhancement ranges from 6 to 21 dB in the frequency band from 1.83 to 2.17 GHz.

In order to improve the efficiency and accuracy of antenna optimization, an adaptive evolutionary neural network (AENN) based optimization design method for wideband dual-polarized antenna is proposed. The proposed AENN is composed of two networks. The first network is used to predict the structural parameters of the antenna, and the second network uses the structural parameters as input to verify the results of the first network. This method only needs a small number of data set to pre-train the network, and then, through the advanced workflow, while updating the data set, the two networks can evolve iteratively, and finally the antenna structural parameters under the expected electromagnetic response can be obtained. Taking two wideband dual-polarized antennas as numerical examples, this method is compared with other advanced antenna optimization methods, and the effectiveness of this method is verified.