Coupled transmission line resonator band-pass filter with transversely rotated resonators for improved selectivity

摘要

A radio frequency, coupled transmission line, band-pass filter composed of a cascade of transversely rotated electro-magnetic resonators along the length of a conducting tube providing for both adjacent and non-adjacent couplings so as to create real frequency transmission zeros and hence a more selective band-pass response together with an in-line configuration.The present invention uses a hollow conducting tube of polygonal or circular cross section and in line cascade of resonant rods all of which lie in a common centre line extending along the length of the tube. Any one of the cascade of resonant rods may be rotated by specified amounts, in the plane of the conducting tubes cross section, so as to create not only coupling to its most immediate neighbour but also to non-adjacent resonant rods further along the cascade.