Phase-Variable and Matching-Tunable Smart Antenna Using Flexible PDMS Cavity for Adaptive Wireless Communications

Fast-growing Internet of Things (IoT) has drawn intensive attention and massive applications, leading to high demand for wireless communications in complex environments. Hence, this article introduces a novel adaptive antenna with a reconfigurable cavity mitigating the impact of environmental interference. The flexible air cavity is implemented by combination of printed circuit boards (PCBs) and polydimethylsiloxane (PDMS) technologies. By dynamically adjusting the cavity height through air injection and extraction, the coupling between the radiator and the feeding aperture can be precisely tuned, so as to the matching and radiation. This innovative design enables the manipulation of both the magnitude and phase of radiated and reflected signals, effectively minimizing antenna impedance mismatch. Specifically, an antenna prototype achieves a phase shift of 152.22° for the reflected signal whereas 58.54° for the radiated signal, as well as improving the impedance matching by minimum 3.89 dB when various obstacles exist. Furthermore, the radiation gain can be increased by 2.77 dB at 9.4 GHz, reducing the interference effect by up to 96.52%. This adaptive antenna provides phase shift capability and improved performance against environmental interference with low power consumption, demonstrating significant potential for wireless communication systems in complex environments.