This antenna includes a helically formed wire coil having a lower end that is positioned in a connector a solid dielectric material is injection molded into the coil and connector to precisely maintain the coil dimensions and support the coil. An outer cover is injection molded over the coil and dielectric...http://www.google.com.au/patents/US4725395?utm_source=gb-gplus-sharePatent US4725395 - Antenna and method of manufacturing an antenna
