FILTER WITH IMPROVED INTERMODULATION DISTORTION CHARACTERISTICS AND METHODS OF MAKING THE IMPROVED FILTER

摘要

Multi-stage electric filters with improved intermodulation-distortion characteristics and a method for designing such electric filters is provided. In general, the invention may include a multi-resonator electric filter in which one or more of the resonators have been intentionally designed to have a different IP and/or Q than the other resonators in the electric filter. In one case, the electric filters include a 4-resonator Chebyshev narrow pass-band filter with at least the first resonator (1105) having a Q and/or IP different from at least one other resonator (1110) in the filter. The filter thereby has improved IMD power over conventional designed filters while maintaining high Q. In a preferred embodiment the filter may include a superconducting material. The relative Q and IP of the respective resonators in the improved filter may depend on the relative strength of in-band and out-of-band signals. The performance and cost of the electric filter may be optimized by designing the filter to have a relative Q and IP required by the particular application.