On Controlling the Passband and Stopband of UWB Band-Pass Filter

In this article, the passband, and stopband of quarter wavelength stubs-based Band Pass Filter (BPF) are controlled by a straightforward and new method. This method depends on inserting an attenuation pole and tuning the passband by a Circular Slot Ring Resonator (CSRR) and rectangular slot beneath the BPF’s stubs. Hence, controlling the passband width without any further area usage is achieved. The stop-band rejection level and bandwidth are controlled by inserting Band Stop Filter (BSF) after the BPF such that the used rectangular slots beneath the stubs control the stop-band bandwidth. For verification, third-order Chebyshev BPF and Butterworth BSF filters are used. The proposed filter passband is chosen to cover the sub-6 GHz different 5G bands. The proposed BPF has an ultra-wide 3 dB passband of 2.97 GHz (2.35 GHz-5.32 GHz) and a 20 dB stopband of 4.59 GHz (6.18-10.77 GHz). The proposed BPF filter is fabricated, measured, and the results are in good agreement with their simulated counterparts.