Miniaturised slot antenna for biomedical applications

An implantable slot antenna with a miniaturised size of 139.7 mm³ (10 × 11 × 1.27 mm) for biomedical applications is proposed. Operating at the Medical Implant Communications Service (MICS) band, miniaturisation of the antenna is realised by etching a meandered slot on the top metal with one end open. A microstrip line is utilised as excitation with a shorting connected to the radiator. In addition, two U-shaped stubs are adopted to match the feeding impedance to 50 Ω. The antenna is simulated in a one-layer skin model as well as in the arm of a human model and measured in skin-mimicking tissue. Good agreements can be obtained and the measurement results show that a broad bandwidth of 28.3% (from 354 to 469 MHz) for |S₁₁| less than - 10 dB can be achieved.