Double resonance L-C trap for dual-band dipole antenna

L-C trapped dipole has been a popular dual-band antenna for several decades. Its basic operating principle relies on a couple of parallel resonant circuits that cut-off a part of the dipole branches at a specific design frequency. In this paper a double-frequency (series and parallel) resonant circuit has been designed to operate as a trap and it has been experimentally tested. The advantage of this solution is that it makes the antenna input impedance more uniform in the sub-bands, improving its matching performances.