Silicone rubber-nanoceramic composites for 5G antenna substrates

Here, the eligibility of silicone rubber-nanoceramic composites as flexible substrates for sub-6 GHz 5G antennas is investigated. Two different composites are prepared using the solution mixing method, namely mono and hybrid composites. The reflection and transmission coefficient (S-parameters) of composites are measured using a rectangular waveguide-based transmission line technique in conjunction with a Vector Network Analyzer (VNA) at C-band frequencies (4-8 GHz). The Nicolson-Ross-Weir (NRW) algorithm is adopted to extract the complex permittivity and loss tangent of the material under test. Due to the synergetic effect, the silicone rubber hybrid composite (0.12BiVO4+0.12LaNbO4) exhibits the advantage of a lowered loss tangent while retaining a good dielectric constant at 5.78 GHz. A rectangular microstrip patch antenna is designed and simulated with CST software using 0.12BVO/0.12LNO/0.76SR composite as a substrate. Moreover, based on the simulation, the antenna with the proposed substrate has acceptable performance at 5.78 GHz with the return loss, directivity, and gain of -25.05 dB, 5.46 dBi and 2.74 dBi, respectively. As a result, the composite material's ability to act as a suitable substrate for a 5 GHz Wi-Fi antenna is confirmed.