Periodically Slotted Coupled Mode Leaky Coaxial Cable with Enhanced Radiation Performance

A novel technique to periodically modulate the aperture of a coupled mode leaky coaxial cable (LCX) is presented in this communication. The surface wave (monofilar mode) over the cable is modulated by periodically slotted aperture, converting it to a leaky wave. This leaky wave due to periodic modulation complements the leaked bifilar mode, thus enhancing the radiation efficiency of the LCX. The numerical results obtained through CST simulation are presented to prove the coexistence of a complex surface wave and a leaky wave over the surface of periodically modulated cable. As a proof of concept, a periodically slotted LCX operating at 4.5 GHz is designed and fabricated. Parametric studies are performed to observe the influence of the key parameters on the radiation performance. The measured results reasonably agree with the simulations.