生物医用冲激脉冲辐射聚焦天线的设计与优化

Design and Optimization Research of Impulse Radiating Focusing Antenna Used in Bioelectric Applications

ps级电场脉冲的宽度远小于生物组织的细胞核膜与细胞膜的充电时间常数(几十纳秒和几百纳秒),且具有丰富的超宽带频谱(几乎从直流到GHz),因而具有很高的时间分辨率和空间分辨率。文章提出一种由同轴TEM馈电的圆锥结构与椭球面反射器组成的超宽带冲激脉冲辐射天线,通过冲激脉冲辐射天线将高强度皮秒电场脉冲传输至生物组织浅层靶点位置形成有效的聚焦。仿真分析了4种模型在不同条件下聚焦区域的电场分布,并对天线结构进行了优化选择。结果显示该天线在焦点区域的电场分布保持了输入脉冲的冲激特性,电压驻波比小于2,且具有稳定的增益和场方向图,x轴方向电场分布的半峰带宽小于20mm,y轴和z轴方向小于10mm。

Picosecond pulses is much smaller compared to the membrane and nuclear membrane charging time of biological tissue（tens of nanoseconds and a few hundred nanoseconds）,and it owns a rich spectrum of ultra wide band（almost from DC to GHz）,which indicates high temporal resolution and spatial resolution.A wideband impulse radiation antenna（IRA） system was developed,which was composed of a cone structure with TEM coaxial feed and a prolate spheroidal reflector.It can focus the electromagnetic energy on a special target effectively.The E-field distributions of four kinds of models under different conditions were simulated,which could provide some optimal choices for the antenna design.The results shows that gain and field pattern of the antenna are stable,and voltage standing wave ratio is less than 2.At the same time,the pulse of focusing region maintains the input impulse characteristics,while the full width at high maximum of the electric field distribution generated in x-axis direction is less than 20mm,with y-axis and z axis 10mm.