Novel Broadband Antennas for Future Mobile Communications

Compact planar antipodal endfire broadband antennas based on novel windmilllike shape are proposed in this paper for future mobile applications. Asymmetric structure of the proposed antennas makes these antennas to radiate in boresight direction, while antipodal structure provides wideband behavior. In the first phase, an ultrawideband antenna is designed using an FR4 substrate with a size of 34 mm x 30 mm, for the frequency range from 4 to 10 GHz and a peak gain of 5 dBi. This antenna is then upgraded to Antenna-II, to shift its frequency band to more than 10 GHz and up to >150 GHz. To improve the performance of Antenna-II, a low-loss substrate Rogers RO4232 is used. The final optimized antenna achieves at least 175% fractional bandwidth in the frequency range from 10 to >150 GHz and exhibits a peak gain of 8.7 dBi while maintaining an overall average gain of 6.4 dBi in the entire frequency range. Design as well as the performance analysis of this antenna is also investigated for low earth orbit-to-low earth orbit intersatellite link applications with its power analysis.