Compact Tri-Band Bandpass Filter Based on Hybrid Resonator With Improved Selectivity Performances

Abstract

Abstract-A novel microstrip tri-band bandpass filter is proposed and implemented using hybrid resonator with independently controllable center frequencies and good in-between isolation. This hybrid resonator is constructed by a stepped-impedance stub resonator and a single end shorted resonator. The stepped-impedance stub resonators are applied to achieve the first and second passband, while the third passband is implemented by single end shorted resonators. By applying the even-odd mode approach, the resonance frequency ratio between even mode and odd mode inside the stepped-impedance stub resonators is attained. Furthermore, the filter with multi-path coupling structure can generate the transmission zeros at the edge of the passband, which can effectively improve the filter passband selectivity. Finally, a tri-band filter operating at 1.91, 2.73, and 3.45 GHz is designed and fabricated. The measurement results accord well with the full-wave electromagnetic designed responses.

Application of multidisciplinary treatment in the diagnosis and treatment of patients with advanced colorectal cancer：a retrospective study in China

“…As the division of hospital departments becomes more and more detailed, it is impossible to provide accurate diagnosis and the best treatment plan for tumor patients by relying only on a certain department [11].The MDT model breaks down the barrier boundaries of the disciplines, coordinates the collaboration and cooperation among disciplines from the level of hospital management, standardizes the behavior of clinicians in tumor diagnosis and treatment, and effectively improves the utilization rate of medical resources. The Institute in the hospital in 2018 by the National Health and Health Commission recognized as the rst batch of digestive tract tumor MDT pilot hospitals in the country, and in July 2021 formally implemented the MDT full coverage of patients with malignant tumors, multidisciplinary diagnostic and treatment services, including the initial diagnosis of malignant tumors, as well as the treatment of patients with cancer whose condition has changed in the course of treatment deviated from the expected.…”

Design of tri‐band bandpass filter using symmetrical open stub loaded step impedance resonator

“…Introduction: With the rapid growth of high-performance heterogeneous wireless communication systems, the use of multiband bandpass filters (BPFs) is increased. In order to meet the multiband specifications, several design techniques are reported in recent years [1][2][3][4][5][6][7]. In [1], a tri-band BPF is presented using a dual-band stub filter with a singleband filter.…”

“…Moreover, the obtained passbands are at low frequencies compared to the previously discussed topologies. In [5], a tri-band BPF is presented using hybrid resonator consisting of stepped impedance stub loaded resonator and single impedance stub resonator. The design topology is compact and shows good filtering response in the first and second passband, however, the last band has high insertion loss which might not be suitable for practical applications working at 3.5 GHz.…”

“…5 shows the fabricated prototype of the proposed tri-band BPF. 1.575/2.45/3.5 0.8/0.9/0.9 0.0416 15.8/3.8/2.5 [4] 1.575/1.8/2.4 0.7/0.9/0.9 0.0252 6.1/3.5/3.1 [5] 1.91/2.73/3.45 0.51/0.69/1.15 0.0182 10.6/3.8/3.4 [6] 2.4/3.5/5.2 1.2/1.1/1.5 0.0677 5/3.7/4.2 this work 0.9/2.45/5.5 0.64/0.68/1.4 0.020 23/10/17…”