A novel fractal for improving efficiency and its application in LTE mobile antennas

In this article, we apply a novel fractal in arms of an antipodal dipole for antenna miniaturization that uses the Chu's sphere very effectively to keep antenna efficiency very high in comparison with its counterparts like Koch dipole/monopole. Then, a formula is extracted to determine the first resonance of the dipole. We used this method to design a mobile antenna at LTE13 band (746–787 MHz) which is well known for leading the size of a common dipole antenna to be very large for a handheld mobile. The proposed design shows 40% size reduction in comparison with a common dipole while antenna efficiency is better than 79.28% with S11 greater than 10 dB. It also covers LTE band2 (1850–1990 MHz) with S11 and efficiency better than 6 dB and 78.91%, respectively. The overall size of the printed antenna is 62 × 115 × 1.6 mm3. The simulation and measurement results verify the presented calculations very well. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2429–2434, 2015