A novel approach for the design of a bandpass filter with attenuation poles using a linear relationship

In this paper, a novel design method for bandpass Alter with attenuation po les (BAP) is presented. The changed inverter element values due to insertin g either capacitors or inductors can be optimized using the linear relation ship between inverter element values of a conventional bandpass Alter (BPF) and those of the BAP using the Touchstone program. A 1800-1825 MHz bandpas s Alter with attenuation poles for duplexer lj is designed and fabricated u sing coaxial dielectric resonators. The validity of this design approach is demonstrated by a computer simulation. The resonators are simulated equiva lently as shorted lossy transmission lines. The measured results of center frequency, bandwidth, and attenuation pole frequencies closely agree with t he design values.