A Small Antenna of High Radiation Efficiency Employing a Ground Radiator

Abstract

This paper introduces the method to utilize a terminal ground as a radiator only using reactive components without an antenna structure. Characteristics of the proposed antenna is compared with that of the meander IFA on the same ground plane(40×20 mm 2 ) for the bluetooth band. From simulation and measurement data, it is found that the proposed antenna using only capacitors provides the highest radiation efficiency. This is because of that the higher inductance reduces radiation resistance of a ground and the capacitor has a lower loss resistance comparing to that of the IFA or the inductor. In spite of the high radiation efficiency, the area (5×2.5 mm 2 ) of the proposed antenna is less than half of the area (12×2.5 mm 2 ) of the IFA.