Compact and high performance lowpass filter using complementarily combined characteristics of slot and open stub

摘要

The invention proposes a low-pass filter having an excellent cut-off (cutoff) characteristic of a stop band UWB using a parallel open stubs of the slots in the ground plane and the front and class. A pair of ssang open stubs of the ground plane formed on the front slot and the class forms a periodic stop band. Slot portion and the open stub portion size is the other of the stop band of the other locations in the frequency band of the pass band to form a one of a slot and the open stubs. The slot unit electromagnetic length is formed microstrip line open stub part electromagnetic length long slot portion first attenuation pole ahead of microstrip lines open stub first attenuation pole portion than is the structure that determines the low-frequency characteristics of the entire Filter . When positioned to increase the width of the slot adjacent to the two slots, due to the coupling between the slot has a attenuation pole can be obtained a very excellent cut-off characteristics, go to the low frequency band. Further, if the deformation the coupling gap is formed in a meander line shape it can be obtained a low cut-off frequency and further improved cut-off characteristics.