STUB TYPE BANDPASS FILTER

摘要

A bandpass filter comprises a line interconnecting input and output terminals. Three stubs are connected to the line at three different locations at a spacing which is 1/8 the wavelength of the centre frequency of the passband. Each stub is grounded at one end and open at the other and each stub has a total length which is 1/4 the wavelength of the centre frequency. The two outer stubs are connected to the line at a position on the stubs which is 1/6 the wavelength from the grounded end. The middle stub may be connected to the line at a position on the stub which is either 1/4 the wavelength of the centre frequency or 1/8 the wavelength of the centre frequency. The filter operates to provide greater rejection of waves double or treble the passband .