Coaxial Waveguide Based Left-Handed Transmission Line

In this letter, a new realization of left-handed transmission line (LHTL) is presented; the proposed structure is realized by periodically loading the coaxial waveguide with gaps in the inner conductor and wires between the inner and outer conductors, the gaps and wires act as series capacitors and shunt inductors. The dispersion characteristic of this new LHTL is analyzed by means of high frequency structure simulator (HFSS) eigenmode simulation and microwave network theory, which exhibits LH behavior over a 60% bandwidth. A backward wave behavior is unambiguously demonstrated from HFSS driven modal simulation. The phase front is observed to be in the opposite direction with respect to the energy one for a finite nine-unit cell prototype.