Incorporated substrate integrated waveguide filters in propagative and evanescent mode: Realization and comparison

The study presents the results of using the incorporated substrate integrated waveguide (ISIW) technique for realization and comparison of propagative and evanescent mode H-plane filters. The basic SIW filter of resonant cavities is compared with filters loaded with circular dielectric resonators, either in propagative or evanescent mode. The results show that the ISIW technique can be used to implement the evanescent mode filter as well as the propagative mode one. The control of the central frequency and the bandwidth of the evanescent mode ISIW filter, which has been presented in this paper, is more convenient than the propagative mode one and achieves only with the change of one parameter. The use of ISIW technique is claimed to reduce the size of the filter, required precision in designing process and the cost of manufacturing process, at the cost of increasing the losses. The ISIW filters have been manufactured with the standard printed circuit board (PCB) process and fairly compared with each other. The size reduction in evanescent mode ISIW filter is impressive and the frequency response characteristics have been improved. Good agreement with the simulated and measured results has been shown.