天线阻抗的实时检测及自动校正系统设计

摘要

设计个低成本、全集成的天线阻抗自动校正系统以实现最大的功率传输及最好的链路性能.该系统包含2个独立的环路:第1个环路通过对并联LC调谐网络的控制实现对阻抗实部的实时检测与自动校正,而第2个环路通过对串联LC调谐网络的控制实现对阻抗虚部的实时检测与自动校正.在这2个环路中,调谐元件采用的是与标准CMOS 工艺兼容的MOS可变电容,以实现单片集成和连续调节.在第1个环路中,除了检测阻抗的实部信息外,还检测虚部的正负特性作为第2个控制准则来确保环路的稳定性.在不同的天线阻抗下,对该系统的性能进行仿真验证.研究结果表明:对于不同的天线阻抗,都能快速地校正到目标阻抗50Ω;调谐网络的插入损耗低于1.5 dB;与固定阻抗匹配系统相比,传输功率可高达3.7 dB.%A low cost and fully integrated automatic antenna impedance correction system was presented to realize the maximum power transfer and the best link quality, which consists of two independent loops. The first loop realizes real-time measurement and automatic correction of resistance by controlling a parallel LC tuning network, whereas the second loop achieves automatic reactance compensation by controlling a series LC tuning network. In both loops, MOS which are compatible with standard CMOS processing were applied as tunable elements to realize monolithic and sequential tuning. For the first loop, besides the intermediate resistance, the sign of the intermediate reactance was also detected as the second control criterion to enforce operation into a stable region. The performance of the proposed system was verified for different antenna impedances. The results show that all matched impedances are clustered around the target impedance 50 Ω quickly. The insertion loss of the tuning network is less than 1.5 dB. The power improvement can be up to 3.7 dB compared with the fixed impedance matching system.