Capacitive coupling of discrete micro-sized gaps for radiofrequency applications

This study investigates the performance of a passive thin metallic object containing micro-sized gaps exposed to a plane wave excitation. This study has potential applications for emerging antenna fabrication techniques where the conducting sections are made from discrete metallic sections. This includes antennas composed of nanomaterials and conventional inkjet-printed antennas. Electromagnetic simulations showed metallic sections separated by a micro-sized gap were found to capacitively couple. The coupling can be enhanced by reducing the size of the gap, increasing the width of the metallic object or by filling the gap with a permittivity greater than unity. It should be noted that the DC value of parallel plate capacitor is not strictly valid at radiofrequencies - however, this study shows that the DC value of capacitance is a reasonable approximation and is useful to understand the behaviour.