电磁晶体 meaning in English
electromagnetic crystals
Examples
- A patch antenna with air holes in the substrate has been designed . the finite - difference time - domain ( fdtd ) method together with the perfectly matched layer ( pml ) boundary treatment has been used to study the performance of the antenna . it is shown that the surface waves are significiently suppressed , the frequency bandwidth is improved , the sidelobe levels are reduced and consequently the gain in the forward direction is improved by 14 db ( about 4 db higher than the value reported previously )
设计了一种基底钻周期圆孔结构的电磁(光子)晶体贴片天线，用fdtd方法并结合pml吸收边界条件对该天线进行了研究，结果表明本文所设计的基底钻孔型电磁晶体贴片天线取得了多方面的性能改善，与普通天线相比，基底中的表面波受到很大抑制，天线的带宽增加，远场方向图上天线的旁瓣和背瓣被明显削弱，向前辐射的增益由原来的12db增加到26db ，增加了14db ，比文献上报道的gonzalo等人的研究结果提高了4db 。 - The performance of the pbg antenna using the new pbg cover together with a pbg substrate is studied by the fdtd method together with the pml boundary treatment . the numerical results show that a more focused beam radiated in the broadside direction is achieved . the gain of the pbg patch antenna in the forward direction is improved by about 6 db . the radiation directivity is improved significantly and reaches 11 . 5 db , which is 0 . 4 db less than the maximum value that is allowed physically for this size of the antenna ( this difference is about 4 . 1 db less than the difference achieved by thevenot et al . ,
用fdtd方法并结合pml吸收边界条件，我们对加了这种新的覆层结构并且基底钻孔的复合结构电磁(光子)晶体贴片天线的性能进行了研究，结果证明加了这种新的电磁晶体覆层结构以后，天线的波束收拢很多，并且向前辐射的增益大大提高，与普通天线相比，天线的e面和h面方向图上向前辐射的增益均提高了约6db ，另外，该复合结构天线的方向性系数达到了11 . 5浙江大学博士学位论文db ，与该物理尺寸天线的方向性系数的理论极限值( 11 . 9db )相差0 . 4db ，该差值比thevenot等人设计的电磁晶体覆层天线的相应差值减少了约4 . 1db ，比qiu等人设计的电磁晶体天线的相应差值减少了约1 - A patch antenna with etched holes on the ground plane is also studied . the performance of the antenna at the resonant frequency is analyzed by using the fdtd method together with the pml boundary treatment . the results show that the surface waves are suppressed greatly , the bandwidth is improved and a 1 odb reduction on the sidelobe level is achieved at the 110 and 260 directions in the e plane
全面地研究了地面腐蚀周期圆孔结构的电磁晶体贴片天线在基波频率处的性能，用fdtd方法并结合pml边界处理技术对该天线所取得的研究结果显示，本文设计的地面腐蚀型电磁晶体结构抑制了贴片天线中的表面波，增加了天线的带宽，并有效地削弱了旁瓣，使天线的e面方向图上110和260方向的两个旁瓣被削弱了10db 。