Study on distributed constant type common-mode filter using Mn-Zn ferrite particle/organic material composite film

为了开发一种新型的平衡模数字接口共模滤波器，研究了Mn-Zn铁氧体颗粒/聚酰亚胺复合材料的制备和性能。此外，还研制了新型铁氧体基复合材料共模滤波器，并对其信号传输特性进行了评价。(1)Mn-Zn铁氧体磁粉/聚酰亚胺复合材料的制备研究了Mn-Zn铁氧体磁粉与聚酰亚胺介质复合材料作为共模滤波器的可能性。研究了两种制备方法，一种是采用由锰锌铁氧体和聚酰胺酸溶液组成的浆料的旋涂法，另一种是采用浆料的丝网印刷法。在任一种制备方法中，可以通过在300℃左右的低温烧成来制备复合材料。复合材料中铁素体的体积分数约为50%。日 ...更多信息 典型复合材料的静态相对磁导率为5 × 10 - 6，与常规块状Ni-Zn铁氧体的Snoek极限线具有相同的高频特性。相对介电常数在几百兆赫处为50 × 100，这是常规块状Ni-Zn铁氧体的5 × 10倍。(2)共模滤波器的制作采用旋涂和丝网印刷两种方法制作了共模滤波器。在前一种方法中，由于复杂的三维结构很难制作，所以制作的是在同一平面上具有耦合分布线的器件。后一种方法能够制作复杂的多层结构，并通过引入上下面对的耦合线结构，制作出耦合信号线之间具有更高磁耦合的器件。在丝网印刷法制备磁性复合材料时，为了避免磁性复合材料的开裂，采用SiO_2填料和聚酰亚胺作为中间层，制备了一种新型的磁性复合材料。由于磁性复合材料和磁性复合材料具有相同的热膨胀系数，材料的裂纹得到明显抑制。(3)信号传输特性已使用四端口网络分析仪进行了评估制造的共模滤波器。实验结果表明，在GHz频段，共模衰减超过15 dB，在3 GHz时最大衰减可达50 dB。在GHz频段，平衡模衰减小于15 dB。结果发现，新的设备作为一个GHz的共模滤波器具有很大的共模抑制。(4)未来的问题虽然新开发的共模滤波器在GHz频段表现出很大的共模抑制，但平衡模衰减相对较大。为了将其应用于Gbps高级数字接口，平衡模式插入损耗应小于3 dB。目前，我们正在研究一种金属基磁性复合材料作为铁氧体基材料的替代品。由于金属基复合材料的磁导率是铁氧体基复合材料的两倍。在未来的研究中，我们将探讨使用金属基复合材料的共模滤波器。少

In order to develop a new common-mode filter for advanced balance-mode digital interface, fabrication and characterization of the Mn-Zn ferrite particle/Polyimide composite material has been investigated. In addition, the new common-mode filters using ferrite based composite material have been developed, and their signal transmission characteristics have been evaluated.(1) Fabrication method of Mn-Zn ferrite particle/Polyimide composite materialA possibility of the new composite material composed of Mn-Zn ferrite magnetic particle and Polyimide dielectric material for common-mode filter has been investigated. Two fabrication methods, one was a spin-coating method using slurry composed of Mn-Zn ferrite and Polyamic acid solution, the other was a screen-printing method using paste, were investigated. In either fabrication method, it was possible to fabricate the composite material by low temperature firing around 300℃. A volume fraction of the ferrite in the composites was around 50%. Th … More e typical fabricated composite material exhibited a static relative permeability of 5〜6, same tendency of high frequency property as the Snoek's limit line of the conventional bulk Ni-Zn ferrite. The relative permittivity was 50〜100 at several hundreds megahertz, this was 5〜10 times higher than that of the conventional bulk Ni-Zn ferrite.(2) Fabrication of common-mode filterBy using two methods of spin-coating and screen-printing, the common-mode filters have been fabricated. In the former method, a device with coupled distributed lines in the same plane was fabricated, since it was very difficult to fabricate the complicated three dimensional structure. The latter method enabled to fabricate the complicated multilayer structure, and the device with a higher magnetic coupling between coupled signal lines by introducing upper and lower facing coupled line structure was fabricated. In the screen-printing method, in order to avoid the cracking of the magnetic composite material, a new nonmagnetic composite with SiO_2 filler and polyimide as a dielectric interlayer was introduced. Since both magnetic and nonmagnetic composite materials had same thermal expansion coefficient, the crack of the materials was markedly suppressed.(3) Signal transmission characteristicThe fabricated common-mode filters have been evaluated using a four-port network analyzer. From experimental results, the common-mode decay was over 15 dB in GHz band, and the maximum decay was up to 50 dB at 3 GHz. The balance-mode decay was below 15 dB in GHz band. It was found that the new device functioned as a GHz common-mode filter with a large common-mode rejection.(4) Future issuesThough the newly developed common-mode filter exhibited a large common-mode rejection in GHz band, the balance-mode decay was relatively large. In order to apply it to Gbps advanced digital interface, the balance-mode insertion loss should be less than 3 dB. We currently investigate a metal based magnetic composite material as a substitute for ferrite based material. Since the metal based composite material has two times higher permeability than that of ferrite based one. In the future, we will investigate the common-mode filter using metal based composite material. Less