Low-profile, Electrically Small Meander Antenna Using a Capacitive Feed Structure

The present paper describes a capacitive feed (C-feed) for small, low-profile linear antennas. A meander line, which is the radiating element, in such antennas with a metallic back conductor electromagnetically couples a metallic feed plate placed between the meander line and the back metal (ground). This antenna has a very small leakage current on the outer surface of the coaxial cable and can control the imaginary part of the input impedance. The impedance characteristics and the antenna gain of -10dBi are discussed based on simulated and measured results, which demonstrate successful achievement in the impedance and antenna gain for a RFID tags etc.