出版社：Society for Microwave Technique, Technologies and Systems, Serbia and Montenegro IEEE MTT-S Chapter
摘要：Microstrip planar waveguides are popular and widely used passive components. They play an important place in microwave hybrid integration (MIC). Microstrip, as a planar technology, is, also, compatible with microelectronic technology and has a future in microwave monolithic integration (MMIC). Passive components at microwave frequencies, especially at lower bands, are still large and occupy a lot of space. One of the main goals for all passive components, including that in the microstrip technology, is miniaturization. Solution for the miniaturization of the microstrip structures can be a periodical variation of the characteristic impedance, ZC, along the microstr ip signal line. It forms a photonic bandgap (PBG) structure. PBG structures, as it is known, exhibit slow-wave characteristics in the pass-band near bandgap [1]. The structure can also exhibit an additional slow-wave effect owing to decrease of the propagation velocity (L`C`)-1/2. It is based on increasing both distributed inductance L`and capacitance C`along the microstrip line. At the same time, the average ratio of the inductance and capacitance should remain relatively constant (usually around 50 .) for matching input and output lines (usually 50 .lines). Previous solution for the microstrip periodic strictures was etching in the ground plane [2]. The etched ground plane must be far enough from any metal plate, which causes packaging problems. The packaging problems are with space, cooling, and mechanical strength. Also, there is a technological problem with etching of the both sides of the substrate. Next solution is to modify only the microstrip line without etching in the ground plane [3].
