Patent ID: 7142837
Filing Date: 2006-11-28
Classification: H01P

Abstract:
1. A multiple-section bandpass filter for filtering broadcast communications, the filter having coupling bandwidths between adjacent filter sections that establish a frequency band for the filter between f L and f H , the filter comprising: a waveguide having a first segment and a second segment adjacent to each other in a direction perpendicular to the signal propagation direction of each segment, and a connecting segment that has a perpendicular orientation to that of the first and second segment and that connects a cavity of the first segment with a cavity of the second segment to form a continuous cavity through which a signal propagates along a substantially U-shaped path, each segment of the waveguide having a predetermined groundplane spacing that creates a lower cutoff frequency f a plurality of resonators located in each of the first and second waveguide segments, each resonator comprising a conductor that extends into the waveguide in a direction substantially perpendicular to the direction of signal propagation, adjacent resonators in each of the first and second waveguide segments having a separation that establishes said coupling bandwidths without the need for a passive decoupling structure being located between them; and a cross coupling conductor connected between the first and second waveguide segments that provides capacitive or inductive coupling between a first resonator of the first waveguide segment and a second resonator of the second waveguide segment, wherein the first and second resonators are not adjacent to each other along the signal path.