In this paper, an extremely low-profile ferrite dipole antenna operating on the VHF band (30–300 MHz) is proposed. The design antenna consists of 44 plate-type ferrite cells arranged into two stacked ferrite layers: a bottom ferrite layer with 2 × 12 grid cells and a top ferrite layer with 2 × 10 grid cells. The antenna is excited by an electric loop feeding structure and maximum gain performance is achieved when the loop feeding structure has five loops. To validate the performance of the proposed antenna, an antenna prototype is fabricated and tested at an outdoor range. The antenna weighs 1.45 kg and has electrical dimensions of approximately 0.0636 × 0.0112 × 0.0008 λ L 3 at the lowest operating frequency of 30 MHz. The measured realized gain varies from −31.48 to −2.44 dBi within the VHF band. Reasonable agreement is also obtained between the measurement and simulation results. To assess the performance of the proposed antenna, it was mounted on the integrated mast of an offshore patrol vessel (OPV) model. The antenna on the OPV was also simulated and the results discussed.
Effect of lattice mismatch on magnetic properties of acicular spinel iron oxide particles with crystallized cobalt ferrite layer
