A novel modular CSRR-based SLA 3D printed waveguide filter for c-band radar applications: suitable for various substrate thicknesses

The design of filters used in waveguides, which are crucial components of high-frequency communication systems, plays a significant role in improving system performance. In this study, the usage of metamaterials is first proposed, the SLA 3D printing method is used to design and fabricate CSRR meta-resonators-based bandpass waveguide filters (WGFs) with different filter orders for C-band (4-7.5 GHz), and simulated and measured filter performances are compared. Since the proposed novel WG structure is modular, it allows the design of C-band WGFs using different thicknesses of substrate materials. Also, the number of unit elements can be increased and any number of meta-resonators can be inserted to design filters of different orders ranging from 1 to 5. The electrical length of the WGF/WG structure can be changed according to the needs of the applications. The resulting WGFs demonstrated superior RF performance, being 50% lighter than comparable models found in the literature. Over the relevant frequency range, the filter exhibited return losses between 31-43 dB, insertion losses from 0.1 to 0.35 dB, FBW ranging from 12% to 16%, and quality factors between 6.23 and 8.28, depending on the filter order. The obtained experimental results align closely with the simulation predictions, confirming the effectiveness of the design.