This section provides background information related to the present disclosure which is not necessarily prior art.
Wireless application devices, such as laptop computers, cellular phones, etc. are constantly being redesigned to reduce their sizes and costs while improving their performance. Laptop computers, for example, have generally become sturdier and more visually pleasing as a result of design improvements. In anticipation of consumer demand for thinner, ultra-low-voltage devices, many laptop providers have begun to replace plastic covers with metallic ones. Many laptop covers are currently being fabricated, e.g., from magnesium/aluminum alloy materials. To allow laptop antennas to radiate freely in a tight environment, laptops have traditionally been provided with “antenna windows” for antenna ground clearance. Because a metallic cover can absorb energy and detune the impedance during laptop use, optimal placement of antennas in such a laptop becomes more complicated.
FIG. 1 illustrates a conventional laptop antenna configuration 20. A cover 24 includes a bezel (not shown) for a display panel 28. An antenna 32 is mounted next to the display panel 28. Plastic laptop covers commonly include the antenna configuration 20. Typical return loss and efficiency for the configuration 20 when used in a plastic cover were computer-simulated by the inventors and are shown respectively in FIG. 2 and FIG. 3. As shown in FIG. 3, peak total antenna efficiency is approximately −2 decibels (dB). If the antenna configuration 20 is used in a metallic cover, there may be considerable degradation in return loss and efficiency. For example, computer-simulated return loss and efficiency for the configuration 20 when used in a 96% alumina cover are shown respectively in FIG. 4 and FIG. 5.