Dielectric Waveguide Band-Pass Filters with Broad Stop Bands

Techniques for the design of band-pass filters using dielectric waveguide gratings are discussed. Direct-coupled-resonator filter theory is applied to synthesize a prescribed pass band having a Chebyshev or maximally flat characteristic, and at the same time a broad, absorptive stop band is provided through the use of parallel-coupled gratings. Experimental results are also presented which show good agreement between theoretical and measured results.