The design of waveguide filters based on cross‐coupled resonators

Abstract

In this article, two novel microstrip band-stop filters using the gradually variational stepped impedance hairpin resonator with DGS or not are presented. By using the gradually variational stepped impedance hairpin resonator, the filters have remarkable advantages, such as compact size, simple structure, and high selectivity. Two band-stop filters are designed, fabricated, and measured. The measurement results show good agreement with the simulation ones. ACKNOWLEDGMENTSThis work was supported by National Natural Science Foundation of China under Grant 61171051. The authors would like to thank the persons in Agilent Open Laboratory in Beijing, for their technical assistance. ABSTRACT: This article addresses the physical realization of crosscoupled waveguide filters based on electromagnetic (EM) simulations. For this design procedure, the filter structure is simulated by successively adding one resonator at a time. The desired filter response is achieved without the need of a global optimisation on all the mechanical dimensions within an EM simulator. This reduces the design time required for a crosscoupled waveguide filter and allows the possibility of building high-order waveguide filters with complex crosscouplings. A sixth order X-band dual-band filter with a center frequency of 10 GHz and a fractional bandwidth of 1% is designed using this procedure and presented here as an example. Excellent agreement between simulation results and theoretical results from coupling matrix verifies the proposed approach. THE DESIGN OF WAVEGUIDE FILTERS BASED ON CROSS-COUPLED RESONATORS

Design and Optimization of Rectangular Waveguide Filter based on Direct Coupled Resonators

“…1. Calculate the approximate initial dimensions for all the resonators and irises using the equivalent circuit models based on the coupling matrix as described in [1,6,7] 2. Using the coupling matrix values calculated for the entire filter, obtain just the responses for the first resonator [see Fig.…”

“…The dimensions associated with resonator 1 obtained in step 2 should be slightly adjusted to account for the influence of resonator 2. This can be done with optimizations and has a fast convergence due to the final result being close to the optimum [1]. 4.…”

“…Following the development, as shown in Figure 5 (b), the HFSS simulation reaction (in solid lines) approximates its response from the coupling matrix (in dashed lines). The equivalent coupling matrix of the scheme of step three is: V. 4 Step Four:…”

“…Traditionally, the design methods for direct coupled filters have been applied to extract the dimensions for direct coupled filters. This design process usually involves the following four main steps: (i) identify the filter order and filter functions according to specification requirements; (ii) synthesis or optimise the coupling coefficients (Mi,j) and external quality factors (Qe) that can realize the desired filter function; (iii) choose the filter type (waveguide, microstrip, etc), and obtain dimensions which can achieve desired specified Qe and Mi,j from electromagnetic (EM) simulations on one resonator and two weakly coupled resonators; (iv) construct the filter in the simulator to get its initial responses [1,2]. Coupled resonator circuits are of importance for design of RF/microwave filters with any type of resonator regardless its physical structure.…”

Design of X-Bandpass Waveguide Chebyshev Filter Based on CSRR Metamaterial for Telecommunication Systems

“…The gap between the inserted metamaterial and the metallic walls of waveguide is less than 30 µm. The procedure used here to design the waveguide bandpass filter is proposed in [38], which depends on the coupling between cascaded meta-resonators. The first waveguide resonator is run and optimized at 10 GHz as shown in Figure 4, the initial length of the waveguide resonator without inserting metamaterial is 40 mm and with inserting metamaterial is 17 mm.…”