The complexity reduction of receivers in ultrawideband (UWB) communication when time reversal (TR) technique is applied makes it suitable for low-cost and low-power sensor systems. Larger antenna dispersion can generally lead to a less stable phase center and will increase the interference in UWB communications based on pulse radio, whereas a higher antenna gain will result in higher channel gain and further larger channel capacity. To find out the trade-off between antenna gain and dispersion, we performed the channel measurements using different antennas in a dense multipath environment and established the distribution of channel capacities based on the measured channel responses. The results show that the capacity loss caused by antenna dispersion cannot be compensated by antenna gain with line-of-sight transmission to some extent, the effect of phase center on the communication system is negligible, and antennas with smaller time dispersion will have a better energy focusing property and anti-interference performance in TR systems.

A W-band slot array antenna based on a substrate integrated waveguide (SIW) for microwave power transmission (MPT) is proposed in this paper. By size optimization, the transition from the rectifier element to the antenna is limited to a small size. It realizes a compact arrangement of the radiating slots, which not only improves the aperture efficiency of the antenna but also makes it easy to integrate into a large-scale array. For antenna testing, a coplanar waveguide–SIW–rectangular waveguide transition structure is added at the end of the antenna, and an antenna with this transition structure is processed by PCB printing technology and measured. The measured reflection coefficient is less than −10 dB at 90–96 GHz, the aperture efficiency is greater than 60% at 93.5–94.5 GHz, the maximum gain is 13.2 dB at 93.5 GHz, and the aperture efficiency is 79%. The test results of the antenna show that the antenna has a good performance and can be applied to the MPT system as a rectenna.