Balanced Single- And Dual-Band BPFS Using Ring Resonators

Abstract

Abstract-This paper presents new balanced single-and dual-band bandpass filters (BPFs), both of which are constructed using two ring resonators. For each BPF, open-circuited stubs are added to one of the two resonators so that the transmitted common-mode (CM) signals can be attenuated, and source-load coupling is established so that two transmission zeros are generated near the edges of each desired differential-mode (DM) passband to sharpen the passband selectivity. The measurement agrees well with the simulation. For the single-band BPF, the measured minimum DM insertion loss is 1.4 dB in the DM passband, in which the CM suppression is larger than 41.6 dB. For the dual-band BPF, the minimum DM insertion losses are 1 and 1.35 dB in the first and second passbands, respectively, in which the CM rejections are larger than 29 and 22 dB.

Compact Step-Impedance Ring Resonator for Quad-Band Band-Pass Filter

“…Therefore, multi-band bandpass filters (BPFs) have been investigated aggressively to satisfy the newly developed multi-service system and the commercial products. Multi-mode ring resonators, step-impedance resonators (SIRs) and stub-loaded resonators (SLRs) are popular for the design of multi-band BPF [1][2][3][4][5][6][7][8][9][10][11]. However, most previous work mainly focused on the design of dual-band and tri-band BPFs.…”

Compact Split Ring Sir Bandpass Filters With Dual and Tri-Band

“…Currently, with the rapid development of modern wireless communications, bandpass filters with dual-band [1][2][3][4][5][6][7] and tri-band [8][9][10] even quad-band [11] operation become more and more important in communication systems for the multifunctional and miniaturization requirement of portable equipment. The traditional microstrip parallel-coupled halfwavelength resonator bandpass filters have narrow stopband between the fundamental response and the first spurious response, so the stepped-impedance resonator (SIR) [6][7][8] was presented in the past years not only to restrain the spurious responses, but also to shorten the resonator size.…”

“…SIR also can be used to design tri-band even multiband filters for tuning the higher order resonant modes conveniently. The deficiency of this kind of resonator is its resonant frequencies are dependent, and transmission zeros are difficult to implement, especially for the fundamental SIR Commonly, there are the following methods for dual-and multiband filter design: the first is using cascade resonators including the stepped impedance resonator [7,8,12], the second is using two sets of different resonators with two-path coupling [3], the third is using new resonator [2], and the fourth is using dual-mode [1,2] or multimode resonator. In this paper, split ring tri and quad-section SIR bandpass filters with dual-band operation are presented, and compared with dual-band filters with two sets of different resonators or two paths coupling, the new filter sizes are greatly reduced.…”

Stopband-Extended Balanced Filters Using Both Λ/4 and Λ/2 Sirs With Common-Mode Suppression and Improved Passband Selectivity

“…Basically, those balanced circuits designed with careful DM operation concepts [1] have good immunity from CM noises, cancellation of even-harmonic signals, elimination of via holes and etc.. Therefore, RF/Microwave components, such as antennas [2,3], mixers [4][5][6], BPFs [7][8][9][10][11][12][13][14][15], and so on, are realized by their balanced counterparts. Among the conventional mobile devices, the SAW filters are usually employed in front-end modules with operation frequency not exceeding several gigahertzs (roughly around 3 GHz) because of their physical nature.…”