A controllable compact dual-band bandpass filter using loaded open-loop resonators

Abstract

Abstract:A compact composite open-loop resonator based dual-band band-pass filter (BPF) with high selectivity is presented. The outer openloop and inner open-loop are corresponding to the first and second frequency passbands, respectively. The middle ring is used as the couping ring. The analysis of these open-loops has also been performed to indicate the resonance condition of the proposed filter. To demonstrate the proposed concept, the filter is fabricated with a compact size, which is 10.20 mm × 18.32 mm. The microstrip line filter is validated and measured with two passbands centered at f 1 = 3.00 GHz and f 2 = 5.34 GHz. The simulation and measured results are in good agreement.

Dual-/Tri-Wideband Bandpass Filter with High Selectivity and Adjustable Passband for 5G Mid-Band Mobile Communications

“…Using resonators of a filter cell as I/O ports for the other filter cells is an improvement of this method. Due to the embedded structure, the resulting multi-band BPFs usually have compact size [28,29] and adjustable passbands [30,31].…”

Individually controllable dual-band bandpass filter with multiple transmission zeros and wide stopband

“…Dual-band bandpass filters (DB-BPFs) with controllable dual-passbands and wide stopband play an important role in low interference and multiservice wireless communication systems, and up to now, many design methods have been proposed with insert a bandstop performance resonators [1,2], consist of two different size or type resonators with common feed structure [3,4,5,6,7], stepped-impedance resonators (SIRs) [8,9,10,11], stub-loaded resonators (SLRs) [12,13,14,15,16,17,18,19,20,21], other types multi-mode resonators (MMRs) [22,23,24,25], and substrate integrated waveguide (SIW) structures [26,27]. In [1], a synthesizing method is presented to design dualband by consist of a wideband bandpass filter and a stopband filter.…”

“…It is improved the controllable of the two passbands, but the circuit size is relatively large. A more compact DB-BPF using a pair of composite open-loop resonators is reported in [19]. However, weak coupling exists between the outer and inner open-loops which leads to a smaller attenuation in stopband.…”