Compact patch antenna on thick (>800 μm) NiFe2O4 magnetic film

Abstract

In this paper, we demonstrate a thick magnetic film loaded patch antenna which shows great potential in antenna miniaturisation with enhanced performance. First, a microstrip patch antenna is designed on a 3D-printed air substrate which operates at 8.21 GHz with a measured realised gain of 8.2 dBi. Using the solution cast chemical method, we fabricate the nickel ferrite nanoparticle films within the air substrate achieving an estimated film thickness of 875–900 μm. Due to the different film thicknesses, the resonant frequency of the antenna shifts down by 0.75–1.75 GHz, indicating a 9.3%–21.3% of size reduction. At the same time, the bandwidth is improved by 0.16–0.25 GHz. The realised gain and efficiency are increased by 0.6 dB and 6%, respectively, given a good film quality.