Florence Sonnerat

Design of traditional and a novel space-efficient antenna-coupling elements for lower LTE/GSM mobile phones

The mobile phone antennas exhibit a very low real impedance value especially in lower LTE (698-787MHz) and GSM (824-960MHz) bands, since the antennas are electrically small compared to operating wavelengths at these bands. Obtaining sufficiently low reflection coefficient and high TRP in a considerable bandwidth from such an antenna is very challenging without exciting proper currents on the PCB of the device. So the main trend for mobile handset antennas has moved toward using an electrically-small coupler plate to excite those PCB currents. In this way, the input impedance of the coupling element-chassis combination has a relatively high real part and the quality factor of the system is now much more lower than traditional resonant antennas, enabling higher bandwidth potential with the help of a proper matching network. In this paper, this approach is followed to cover lower LTE (698787MHz) and GSM (824-960MHz) standards with a novel hollow coupling element antenna while keeping space available around and inside the antenna, for additional components or even another higher band antenna (DCS/PCS and UMTS).

Wideband LDS antenna using two radiating elements

In this paper, an innovative 4G antenna solution operating in the 698-960 MHz band, is presented. It is composed of two radiating elements recombined in a single feed antenna-system using an integrated power divider/combiner, synthesized thanks to five lumped components. Simulations using realistic SMD (Surface Mount Devices) components allow reaching a matching better than -6 dB, confirmed by measurement and an average total efficiency of 30% over the full frequency band. These results are benchmarked with the performance of measured commercial handset antennas, demonstrating a key improvement of the achievable bandwidth and total efficiency. Proposed solution seems promising in order to address 4G wideband antenna design challenges.

Innovative 4G mobile phone LDS antenna module using plastronics integration scheme

An innovative LDS 4G antenna solution operating in the 698-960 MHz band is presented. It is composed of two radiating elements recombined in a single feed broadband antenna system using a diplexer. This circuit is realized thanks to lumped components, assembled directly on the plastic piece which supports the antenna. Corresponding measurements show a 260 MHz wide bandwidth (for S11@-6dB) and close results when diplexer integration is made onto FR4 PCB. It validates the plastronics integration scheme for innovative antenna module solutions.

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.

Innovative tunable antenna solution using CMOS SOI technology

This paper describes a tunable matching network, fully integrated in STMicroelectronics 130 nm CMOS SOI technology. It is able to correct, on the 2500-2690 MHz band, the antenna mismatch of a cellular phone due to the user interaction (for example the hand impact):any VSWR of 5:1 can be reduced to a value lower than 2:1.