High-Order Superconducting Dual-Band Differential Bandpass Filter Using Symmetrical Composite Right-/Left-Handed Resonator With Wide Stopband

In this letter, a newly dual-mode composite right-/left-handed (CRLH) resonator with fully symmetrical structure is proposed to design high-order high-temperature superconducting (HTS) dual-band differential bandpass filter (BPF). Based on the conventional CRLH unit cell, a dual-mode symmetrical CRLH resonator is developed for constructing dual-band differential BPF. The resonant properties of the proposed dual-mode resonator are investigated by building differential-mode (DM) and common-mode (CM) equivalent circuits (ECs) and their lumped ECs (LECs). Finally, a fourth-order dual-band HTS differential BPF with two DM passbands that operate at 2.45 and 4.94 GHz is designed. Good agreement between the simulated and measured results validates the proposed structure and the design method.