No abstract

Based on a recent study of the ways a phone is held (a grip study), CAD models of the human hand have been generated, and antenna proximity effects for both talk and data modes in mobile phones have been investigated using an FDTD code. The simulation results showed that the hand, and especially the index finger, exhibited a major contribution in determining the total loss when compared to the upper torso alone. The influence of the position of the fingers on the handset was found to be more important when close to the antenna. The palm-handset gap and the index-finger location were the main factors for both absorption and mismatch loss. Different data-mode hand phantoms and configurations were investigated, showing that both "overlapped" and "interlaced" grip styles similarly influenced the antenna's communication performance.

No abstract

In full-duplex radio communication systems like e-UTRAN, CDMA-2000, the radio transmitter (Tx) is active at the same time as the radio receiver (Rx). The Tx and the Rx will be using separate dedicated frequency bands and the Tx-Rx isolation is ensured by duplex filters. However, agile duplexers required for multiband operation are almost nonexistent while dedicating a bank of narrowband filters is bulky and incurs considerable switching losses. In this paper, we propose an approach that dramatically reduces the complexity of the RF frontend, first by replacing the duplex filter with a spatial filter and second, by codesigning the filtering antennas and the RF frontend. The spatial filter is synthesized by equipping the Tx with redundant antennas. By properly weighting the Tx antennas, the Tx signal is selectively attenuated in the Rx direction. The spatial filter can be tuned to different frequency bands as long as the antennas are made tunable. Moreover, the spatial filter may directly benefit from the balanced architecture of the power amplifiers (PAs) thus reducing the total system complexity and insertion loss. Finally, simulation and initial measurement results are provided in a challenging low-frequency band, serving as a proof-of-concept.

No abstract