Novel multi-functional and compact waveguide filter based on various meta-resonators for C-band applications

This paper presents the design, fabrication, and performance analysis of a novel, multi-functional WGF for C-band (4.90–7.05 GHz) applications. The novel WR-159 WG structure is precisely fabricated from Al6065 material by the CNC milling method, and also meta -resonator structures designed in different sizes and geometries are fabricated from low-loss Duroid/RT 5880 substrate material with help of LPKF. Thanks to the designed single WR-159 WG structure, the WGF with four different functions is experimentally realized using a set of meta -resonators that can be mounted and dismounted. These four functions are bandpass/bandstop, narrow/medium/wide bandwidth, shifting operating frequency (5.5, 6, and 6.5 GHz), and filter order (n = 1–7). Filter performance has been verified through simulations and measurements with a vector network analyzer (VNA). For each WGF designed for different functions, simulated and measured performance results, such as for center frequency (f 0 ), return loss (RL), insertion loss (IL), fractional bandwidth (FBW), and quality factor (Q) are compared, and they have good agreement with each other. The proposed modular structure offers a low-cost and versatile alternative that can replace commercial filters.