论文标题
通过非线性能量收获的MIMO无线功率传输的优化优化：RF组合与直流的组合
Beamforming Optimization for MIMO Wireless Power Transfer with Nonlinear Energy Harvesting: RF Combining versus DC Combining
论文作者
论文摘要
在本文中，我们研究了多输入和多输出（MIMO）无线功率传输（WPT）系统，以增强矩形的输出DC功率。为此，考虑到多个接收天线，我们重新审视了Rectenna非线性。对接收器DC和RF组合的多个直立的两个组合方案进行了建模和分析。对于DC组合，我们优化了对通道状态信息（CSI）的发射光束形成，以最大程度地提高总输出直流功率。对于RF组合，我们计算最佳传输并接收光束成形的封闭式解决方案。此外，我们提出了使用RF相位变速器和RF功率组合器的实用RF组合电路，并优化了模拟对CSI的光束形成。我们还通过分析得出输出直流功率的缩放定律，这是发射和接收天线数量的函数。这些缩放定律证实了在发射器或接收器上使用多个天线的好处。他们还强调，RF组合的表现明显优于DC组合，因为它更有效地利用了直流的非线性。提供了两种类型的性能评估，基于非线性直流模型，并基于现实，准确的Rectenna电路模拟。评估表明，通过在接收器处使用多个直流，可以线性地提高输出DC功率，并且在输出DC功率水平方面，RF组合与DC组合的相对增益非常重要，在单个Transmit transmit天线tenna ten-ten-ceceive ten-tece-teceige ten-tece-cepeige ten-tex-cepeige ten-tece-tenna天线设置中的相对增益非常重要。
In this paper, we study the multiple-input and multiple-output (MIMO) wireless power transfer (WPT) system so as to enhance the output DC power of the rectennas. To that end, we revisit the rectenna nonlinearity considering multiple receive antennas. Two combining schemes for multiple rectennas at the receiver, DC and RF combinings, are modeled and analyzed. For DC combining, we optimize the transmit beamforming, adaptive to the channel state information (CSI), so as to maximize the total output DC power. For RF combining, we compute a closed-form solution of the optimal transmit and receive beamforming. In addition, we propose a practical RF combining circuit using RF phase shifter and RF power combiner and also optimize the analog receive beamforming adaptive to CSI. We also analytically derive the scaling laws of the output DC power as a function of the number of transmit and receive antennas. Those scaling laws confirm the benefits of using multiple antennas at the transmitter or receiver. They also highlight that RF combining significantly outperforms DC combining since it leverages the rectenna nonlinearity more efficiently. Two types of performance evaluations, based on the nonlinear rectenna model and based on realistic and accurate rectenna circuit simulations, are provided. The evaluations demonstrate that the output DC power can be linearly increased by using multiple rectennas at the receiver and that the relative gain of RF combining versus DC combining in terms of the output DC power level is very significant, of the order of 240% in a one-transmit antenna ten-receive antenna setup.
