Multistub multimode resonating structure for microwave multiband band‐pass filtering applications

This article proposes a design, analysis, and characterization of multistub resonator with its multimode characteristics for band‐pass filtering applications. First, the principle of resonating structure is explained with related mathematical explanations. Next, the proposed multimode structure is introduced with simple technique to analyze resonating frequency behavior by related mathematics. Through mathematical analysis, it has been presented that the number of resonating frequency and their position can be individually controlled by structural parameter. As a result, the proposed resonating structure can be utilized to design different microstrip band‐pass filters (BPFs). For validating the concept, an ultra wide band (UWB) BPF with −3 dB impedance bandwidth of 4.6 GHz (1.9–6.5 GHz) and a dual band BPF with −3 dB impedance bandwidth of approximately 1.5 GHz (2.7–4.3 GHz) for the first band and around 2.1 GHz (6.2–8.3 GHz) for the second band; have been implemented on Neltec substrate with dielectric constant 3.38, thickness 1.52 mm, and loss tangent 0.0016 and characterized on Keysight vector network analyzer N9918A. All the measured and simulated results are in good agreement with each other.