Microwave Filter Based on Substrate Integrated Waveguide With Alternating Dielectric Line Sections

A new topology of microwave filter based on substrate integrated waveguide (SIW) with alternating dielectric line sections is presented in this letter. The two alternating sections are waveguides without and with a dielectric material acting, respectively, as the inverters and the resonant sections of the proposed filter. This topology allows to easily design and manufacture compact filters with lower losses and higher rejection band than other available SIW realizations. For validation purposes, a prototype of a four-pole bandpass filter, based on alternating dielectric line sections, has been designed and manufactured, including successful experimental results.