Coupling effects of matematerial on sub-wavelength transmission in waveguide Experimenter & Reporter：Wang Juan Collaborator：Lin Yihua Mentor: Le Yongkang
What did we do Study the coupling effects of matematerial on sub-wavelength transmission in waveguide. The influence of different position and depth of nails inside the waveguide to the transmission of microwave. The microwave absorption of different materials inside waveguide.
sub-wavelength transmission Why do we care about sub-wavelength transmission The limitation of the dimensions of waveguide we use to do experiments. Sometimes we need to realize specific sub- wavelength transmission. 要实现波长较长的电磁波的传播，我们需要截止频率比较小的波导，这就意味着波导的尺寸需要做的很大。但是在实际情况中，这是很不利的，因此这就需要我们用电磁特异介质去改变波导腔对微波的透射性能，从而打破这一限制。并且我们还发现介质片不同的花纹对截止频率以下的微波的透射行为是不同的，因此在实验的基础上我们也用CST数值模拟软件进行了不同花纹透射的模拟，发现透射峰的位置和花纹的形状、大小都有密切的联系，我们通过大量的尝试总结出了一些透射峰位的规律，希望在微波的选频方面有实际的应用，这个也是我们这个实验的意义。这块内容将由我的搭档林逸华同学重点介绍。
Experimental setup Agilent E8362C 网络分析仪 Port 1 Port 2
Hollow waveguide of different length
Using foam to fix metamaterial slabs inside waveguide
Result-20mm waveguide with 1 slab inside
Result-20mm waveguide with 2 slab inside
Result-20mm waveguide with 3 slab inside
20mm waveguide with 4 slab inside
Result-70mm waveguide with 5 slabs inside
Theoretical explanation - TBM Limitation of traditional effective-medium theory(EMT) in this case: It could not explain why there are a number of transmission peaks inside the transparency band and what determines the position of these peaks. It also cannot tell us what happens if the inserted metamaterial layers are arranged non-periodically .
Determine the position of peaks – periodical arrangement
Determine the position of peaks – non-periodical arrangement
Non-periodical result
THANK YOU Acknowledge Lin Yihua Le Yongkang Sun Wujiong