Combination of two neutralized coupling element antennas for low LTE and GSM mobile phones

An antenna-system covering the LTE700 and GSM850/900 standards is presented. The proposed structure has been designed to fit in generic handheld devices. It has been manufactured using Laser Direct Structuring technology on a plastic piece. The principal design challenge for the antenna is to cover the target band with a short ground plane (75mm). To be able to cover from low LTE (700–787MHz) up to GSM850/900 (824–960MHz) frequencies with this short ground plane, coupling element antennas are optimized in conjunction with matching networks. In this way, one of the antenna ports covers the low LTE standard, while the other port covers the GSM850/900 frequencies. To obtain an acceptable level of isolation between the antenna feeds, the neutralization technique is used. The proposed antenna was manufactured and the reflection coefficient and total efficiency measurements were performed, showing very promising and competitive performance.