Normal mode helical antenna broad-banding using multiple pitches

The concept of non-uniform helixes is further developed into a multiple-pitch helix to create multiple resonances that can be loaded and combined into a broad, matched bandwidth. The design is elaborated using an example of an antenna for a portable handset. The tools used, design conditions, performance and limitations are presented. The key elements in the design are the tuning of the pitches and the loading of the antenna housing material. A good way to design this antenna is by using computer modeling.