针对遥测胶囊工作在人体消化道中的特点,为遥测胶囊设计了一种新型的微带天线,用于和外部数据接收存储器通信,工作频率为915MHz波段(ISM波段).为了模拟天线在人体消化道内的工作环境,计算模型采用了真实的三维人体数字模型.基于时域有限差分算法,讨论了天线的设计参数,分析比较了天线在自由空间中和人体消化道内的谐振频率、方向图等特性,计算了天线在人体消化道内的比吸收率,求出了最大允许输入功率.结果表明,该天线完全满足遥测胶囊的实际应用要求.
According to the feature of radiotelemetry capsule operating in the digestive tract, a novel microstrip antenna was designed for radiotelemetry capsule communicating with external data recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. A calculation model was constructed by using real three dimension digital model of the human body to simulate the work environment of radiotelemetry capsule. Based on the finite difference time domain method, the design parameters were discussed in detail. Moreover, the characteristics in free space and human digestive tract, such as resonance frequency and radiation patterns, were evaluated. Specific absorption rate computations were also performed to attain the maximum delivered power for the designed antenna. The results indicate that the designed antenna is satisfactory and adequate for radiotelemetry capsule practical use.