Metal covers give mobile handsets rigidity and strength while enabling thinner devices with bigger displays. Metal also provides an effective dispersion of generated heat. Unfortunately, most antennas do not perform adequately in an all-metal cover. For proper antenna performance, plastic is therefore used to cover the antenna portion of the handset. Now, however, a capacitive-feed antenna has debuted that can be enclosed in an all-metal mobile-handset case. This antenna can be used in mobile phones that operate at 900, 1800, 1900, and 2100 MHz. It is compatible with several antenna manufacturing approaches, such as flexible printed wiring board, laser direct structuring (LDS), and molded interconnect device (MID) technologies.
Essentially, this antenna's radiator is placed at the outside surface of the phone chassis and fed by a capacitively coupled feed circuit. The company claims that all available antenna functionality is utilized with no loss of signal performance. This antenna can be used either as a standalone component or integrated, for example, with the all-metal cover. Because there's no need to coat the antenna with plastic, the metal shell and antenna can be constructed as a single unit. The metallic appearance can be applied to the antenna area or the metal cover. In addition, the metal cover can be decorated with paint, leather, or other materials without affecting antenna performance.
Pulse, a Technitrol Co., 12220 World Trade Dr., San Diego, CA 92128; (858) 674-8100, FAX: (858) 674-8262, Internet: www.pulseeng.com.