A Basic Study on a Resonance Characteristics of the Whispering Gallery Mode on a Layered Dielectric Disks Resonator

我们的研究课题是在毫米波带通滤波器中应用由窃窃廊模式操作的层状介质盘谐振器。上（下）盘与下（上）盘之间隔着一段长度为d的气隙。2001年，我们在微波区的实验表明，上述结构适用于带通滤波器。2002年，我们的研究取得了进展。也就是说，我们可以从滤波器的设计理论中估计耦合的两个介质盘之间的耦合系数和外部Q值。通过研究发现，只要给定一个中心频率和带宽，就可以实现理想的带通滤波器。在电磁理论中，我们采用了本研究负责人提出的近似分离变量法来计算耦合两个介质盘的耦合系数。从这些测试中，我们可以确定气隙长度d和从圆盘到用于激励圆盘的矩形介质波导的距离s。我们还进行了实验，以证实我们的分析在毫米波波段的有效性和充分性。这项科学研究补助金的一部分用于这些实验中使用的毫米波源模块。由于窃窃私语通道模式谐振器有许多共振频率，在上述结构中，在期望的带通宽度附近存在杂散带通宽度。然后，我们提出了另一种结构来抑制杂散带通宽。在新的结构中，从上（下）盘不同的盘代替气隙。实验结果表明，该结构可有效抑制带通强度约20dB。（请参阅下一页第一篇文章）

A subject of our research is to apply a layered dielectric disks resonator operated by Whispering Gallery Modes to a band pass filter in millimeter wave band. Upper (lower) disk is separated from lower (upper) one by an air gap length d.In 2001, we concluded from experiments in microwave region that the above stated structure was applicable to the band pass filter. In 2002, we had been progressing in our research. Namely, we could estimate a coupling coefficient between coupled two dielectric disks and external Q value from a design theory for filter. It was found from our investigations that we could realize a desired band pass filter by giving a center frequency and band width. In electromagnetic theory, we used an approximated separation variables method, which had been proposed by the head investigator of this research, to calculate the coupling coefficient of coupled two dielectric disks. From these examination, we could decide the air gap length d and a distance s from the disk to a rectangular dielectric waveguide which was used to excite the disk. We had also performed experiments to confirm our analytical usefulness and adequacy in millimeter wave band. A part of this Grant-in-Aid for Scientific Research was spent on a millimeter wave source module which was used in these experiments.As the whispering gallery modes resonator has many resonance frequencies, spurious band pass widths exist near the desired band pass width in the above stated structure. Then, we proposed another type of structure to suppress the spurious band pass widths. In new structure, different disks from the upper (lower) disk were substituted for the air gap. We confirmed experimentally that the new structure suppresses the spurious band pass strength about 20dB. ( Refer the first article in next page)