This article proposes a 3.1-5 GHz ultra-wideband antenna, defined by a -1 dB return loss.The simplified planar antenna structures, compact size, and low profile make it profitable to the application of the embedded antenna in wireless universal serial bus dongle devices. The slit shape on the monopole radiator is tuned for miniature antenna size. A parasitic stub on the ground is adopted to increase antenna bandwidth for achieving 3.1-5 GHz impedance bandwidth. To reduce manufacturing cost and practical fabrication, we also propose a simplified rectangular antenna structure. It is found that wideband characteristics of the simplified rectangular structure antenna are similar to that of semicircular base structure. Finally, the antenna prototypes are fabricated and the antenna characteristics are measured. The radiation patterns are omnidirectional in azimuth cut. Moreover, the S-parameter of antenna characteristics has been measured. The consistency between the simulated results and the measurement results confirms the practicability of these techniques.
Microwave and Optical Technology Letters 52(5), pp. 1013-1016