Microstrip-Fed Semi-Elliptical Dipole Antennas for Ultrawideband Communications

A microstrip-fed semi-elliptical dipole antenna (MFSEDA) is proposed and designed for ultrawideband (UWB) communications. The antenna has large bandwidth covering the frequency band from 3.1 to 10.6 GHz, radiation patterns similar to those of a conventional dipole antenna, and small size with the dimension of only about one third of the wavelength instead of half wavelength for the lower frequency. With simple and proper modification of the radiation patches, a frequency-notched antenna based on the MFSEDA is also designed and good band-notched performance from 5.0 to 6.0 GHz can be obtained. Measured results show that these MFSEDAs are suitable for UWB applications due to their high performances.