Miniaturization of Planar Monopole Antennas for Ultrawide-Band Applications

A significant 40% reduction in size has been realized for LTCC based beveled planar monopole antenna for UWB applications by simply exploiting its structural symmetry. The miniaturized antennas exhibit wider impedance bandwidth, higher cross-polar radiation, and slightly lower gain at higher frequencies as compared with their unminiaturized counterparts. These effects of miniaturization are confirmed with measurements of both unminiaturized and miniaturized beveled monopole antenna. The final miniaturized beveled monopole antenna of size 17times10times1 mm3 achieved impedance bandwidth of 8.25 GHz from 2.85 to 11.1 GHz, gain from -5.6 to 2.3 dBi, and broad patterns. In addition, both frequency domain and time domain characteristics of the beveled monopole antennas were also carefully investigated with a normalized measured transfer function. They all proved the feasibility of the miniaturization and applicability of this miniaturized beveled monopole antenna in UWB radios.