Abstract: Provided is a biodegradable resin including a urethane bond generated by a reaction of a polyester polymer with a polyvalent isocyanate used as a chain extender. Particularly, provided is a method of preparing a biodegradable resin using a limited amount of the chain extender and having excellent properties, and a biodegradable resin in which nitrogen content is controlled. Therefore, the biodegradable resin which can reduce the use of a harmful component to the human body and environment in the process of preparing the biodegradable resin and can be safely used for packing materials for food or medicine is provided.

Abstract: Provided is a distributed constant type filter. In a stacked body formed by stacking a plurality of printed circuit boards, signal line coil patterns on adjacent printed circuit boards face each another and are electrically connected together at both ends, and ground line coil patterns on adjacent printed circuit boards face each other and are electrically connected together at both ends. Accordingly, the distributed constant type filter has an attenuation characteristic superior to conventional distributed constant type filters while having an equivalent circuit completely different to the conventional distributed constant type filters. In addition, attenuation characteristics can be obtained without being greatly affected by a deviation upon a manufacturing process, and a process of manufacturing the filter is simple.

Abstract: Provided is a distributed constant type filter. In a stacked body formed by stacking a plurality of printed circuit boards, signal line coil patterns on adjacent printed circuit boards face each another and are electrically connected together at both ends, and ground line coil patterns on adjacent printed circuit boards face each other and are electrically connected together at both ends. Accordingly, the distributed constant type filter has an attenuation characteristic superior to conventional distributed constant type filters while having an equivalent circuit completely different to the conventional distributed constant type filters. In addition, attenuation characteristics can be obtained without being greatly affected by a deviation upon a manufacturing process, and a process of manufacturing the filter is simple.