Shielding Effectiveness of “Pigtail” Connections

The shielding effectiveness of a “pigtail” connection between a coaxial transmission line and a ground plane is treated rigorously by the method of moments, as a function of the type and number of pigtails and frequency. The type of pigtail connection is shown to be crucial with regard to radiation and shielding effectiveness, even though the pigtail itself does not radiate significantly. All pigtails are not equal, even though they may be short electrically. A short pigtail is significantly better than a longer one. A long pigtail connection may actually enhance radiation. Finally, multiple pigtails yield significant improvement over the single pigtail only for short pigtails. Results have been compared with the experiment, resulting in good agreement.