The objective of this paper is to develop a wearable circular UWB MIMO antenna array, consisting of four elements, that is capable of detecting and locating tumor cells within a heterogeneous breast phantom. The antenna element operates within a bandwidth from 2.4 GHz to 10.6 GHz when FR4 is used as the substrate, and extends from 2.57 GHz to 12.6 GHz when a Dacron fabric is used instead. The antenna is fabricated and measured, yielding highly similar results to the simulated outcomes. In the suggested detection system, one antenna is used for transmission, while the other antennas receive the transmitted signal. The employed antenna demonstrates gains of 5.49 dBi, 9.87 dBi, 11.9 dBi, and 14.7 dBi at resonant frequencies of 2.84 GHz, 3.87 GHz, 5.83 GHz, and 8.24 GHz, respectively, when a Dacron fabric is used as the substrate. Moreover, the proposed antenna exhibits a flexible shape with minimal vertical and horizontal bending effects across the entire operating frequency band. The antenna has a compact size of 42.85 × 42.85 mm² and is printed on an FR4 substrate with a dielectric constant of 4.5 and a thickness of 1.6 mm for testing purposes. The S-parameters of the suggested system can effectively identify and precisely locate small tumors. Furthermore, the SAR findings indicate that the amount of power absorbed by the breast phantom tissues complies with the IEEE standards, thus confirming the suitability of the recommended antenna for the early detection and localization of breast cancer.

In this paper, a tunable plasmonic absorber composed of an elliptically grooved metallic film sandwiched between two dielectric layers is presented. To understand the optical response of the structure, its absorption spectrum and resonance modes profiles are numerically calculated using computer simulation technology microwave studio. It is shown that the proposed device can provide two absorption peaks, in the near-infrared region, with absorption coefficients dependent upon the polarization angle of the incident light. Therefore, using a Faraday rotator and applying a variable external magnetic field, the device can be converted into a tunable magneto-optic modulator. From a different point of view, the proposed device is applicable as a sensor to measure mechanical rotations from 0 to 90 degrees. Besides, it is discussed that by adding a graphene layer to the structure, a tunable dual band modulator is realized, by which two absorption bands can be adjusted independently. Simulation results show that modulations of absorption per graphene Fermi energy, about 73.33% eV ⁻¹ and 69.54% eV ⁻¹ are achieved for the first and the second peaks, respectively. Taking advantage of the above mentioned effects, the proposed device can be used in several applications including magneto-optic modulation, rotation detection, electro-optic modulation and spectral selective tunable absorption.

The growing interest in reconfigurable intelligent surfaces (RIS) for wireless communications is evident, particularly in addressing challenges beyond the normal incidence condition of electromagnetic waves. This paper introduces an innovative approach to achieve beam steering in reflecting-type array structures, specifically reflectarrays, through the use of Reconfigurable Electro-Mechanical Reflectarray (REMR) technology. The REMR structure, equipped with a cam-shaped actuator beneath each unit cell’s ground plane, serves as the basis for this design. The proposed design involves multiple reflective strips at variable heights, enabling significant adaptability to incident waves at various angles. By incorporating a cam-shaped actuator beneath the ground plane of each unit cell, a mechanical phase shifter acts as a continuous modifier of phase for incident waves, resulting in the realization of the REMR effect. The REMR structure demonstrates consistent phase and amplitude responses, facilitating efficient beam steering. Simulation and measurement results show a remarkable unwrapped phase shift range of \(\sim 200^\circ \) and beam steering over a broad spectrum of incidence angles from \(0^\circ \) to \(70^\circ \). Additionally, the REMR structure maintains stability even when powered off in the “defined gradient mode” due to a memory function preserving gradient states. The fabrication process utilizes 3D printers, offering flexibility and ease of customization. This comprehensive approach holds significant potential for advancing RIS technologies.

A novel low-cost 3D-printed reflectarray is proposed based on a spatial phase-shifting technique. It consists of a layer of patches and a 3D-printed under-layer covered by copper tape that acts as a ground plane. As part of this study, a lowcost fabrication technique is used to design a reflectarray for 5G millimeter-wave frequencies. At 35 GHz, far-field patterns for various radiation angles have been observed, alongside the achievement of reflection magnitude and phase characteristics spanning the frequency range from 20 GHz to 42 GHz. A good agreement is observed between the simulated and measured radiation patterns for the fabricated prototypes. The proposed reflectarray structure is more than 70% efficient.