Broadband and Miniaturized Structure Loaded With Lumped Capacitors for Parasitic Current Reduction

A broadband and miniaturized structure for parasitic current reduction induced on the outer conductor of electrically coaxial cables is presented. The structure consists of a metallic sheet with 10 pairs of symmetrical L-shaped slots embedded. Lumped capacitors are loaded to miniaturize the entire size. The operation of the entire structure is similar to a series of parallel LC resonators. When the parasitic current flowing on the outer conductor of the coaxial cable, the equivalent parallel LC circuit can suppress the current efficiently at the broad bandwidth. Experimental and simulation results are presented and discussed. The structure can suppress the parasitic current at the 250-400-MHz band for a -10-dB transmittance.