Microstrip dual-band dual-path bandpass filter (original) (raw)
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A dual-band microstrip filter topology based on quarter-wavelength coupled-lines inter-connections
2013 IEEE International RF and Microwave Conference (RFM), 2013
A dual-band bandpass filter topology based on coupled-lines is presented. In the topology, two identical coupledlines are cascaded in series and duplicated in parallel. There are then ended with another two identical coupled-lines. The dualpath structure exhibits a 2 nd order dual-band response with three transmission zeros that separate the passbands from each other, and from the rejection band. The odd-and even-mode impedances of the coupled-lines control the bandwidth, passband and out-of-band responses of the dual-band filter. Finally, to verify the concept, a prototype of a dual-band bandpass filter is designed using EM simulator, fabricated on 1.6-mm-thick FR-4 substrate and measured. The resonant frequencies of the two passbands are centered at 1.82 GHz and 2.38 GHz.
A Compact Dual-Band Bandpass Filter Using Coupled Microstrip Lines
Iete Journal of Research, 2022
A quad-mode resonator is proposed for novel design of dual-band bandpass filters (DBBPFs) with good selectivity and compact size. The symmetrical resonator consists of a pair of coupled line sections (CLSs) and a transmission line section (TLS). Odd-/even-mode method is used to clarify the mode characteristics. Four excited resonant modes are applied to produce two passbands. The frequency ratio range can be adjusted by the CLSs, and the bandwidths can be controlled by the TLS. After installing a pair of U-shape coupling arms, a DBBPF with five transmission zeros (s) around the two passbands are designed and fabricated. The measured results are in good agreement with the simulated results, demonstrating that the proposed filter is feasible in practical use.
Compact dual-band bandpass filter using coupled three-line microstrip structure with open stubs
2011 4th IEEE International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2011
A quad-mode resonator is proposed for novel design of dual-band bandpass filters (DBBPFs) with good selectivity and compact size. The symmetrical resonator consists of a pair of coupled line sections (CLSs) and a transmission line section (TLS). Odd-/even-mode method is used to clarify the mode characteristics. Four excited resonant modes are applied to produce two passbands. The frequency ratio range can be adjusted by the CLSs, and the bandwidths can be controlled by the TLS. After installing a pair of U-shape coupling arms, a DBBPF with five transmission zeros (s) around the two passbands are designed and fabricated. The measured results are in good agreement with the simulated results, demonstrating that the proposed filter is feasible in practical use.
2020
Background and Objectives: Due to the rapid development in wireless communications, bandpass filters have become key components in modern communication systems. Among the microwave filter technologies, planar structures of microstrip line are chosen, due to low profile, weight, ease of fabrication, and manufacturing cost. Methods: This paper designs and simulates a new microstrip dual-band bandpass filter. In the proposed structure, three coupled lines and a loaded asymmetric two coupled line are used. The design method is based on introducing and generating the transmission zeros in the frequency response of a wideband single-band filter. A wideband frequency response is obtained using the three coupled lines, and the transmission zeros are achieved using the novel loaded asymmetric two coupled lines. Results: The proposed dual-band filter is designed and simulated on a Rogers RO3210 substrate for WLAN applications. Dimension of the proposed filter is 11.22 mm × 13.04 mm. The electromagnetic (EM) simulation is carried out by Momentum EM (ADS) software. Simulation results show that the proposed dual-band bandpass filter has two pass-bands at 2.4 GHz and 5.15 GHz with a loss of less than 1 dB for two pass-bands. Conclusion: Among the advantages of this filter, low loss, small size, and high attenuation between the two pass-bands can be mentioned.
A dual-band bandpass filter with wide and highly attenuated stopbands is designed using parallel coupled microstrip line (PCML) and stepped-impedance-resonators (SIRs). The proposed filter is composed of a pair of highly coupled PCML-SIR structure and a central resonator using a low impedance rectangular microstrip. Initially, the wide dual-band performance is achieved by creating a transmission zero between those two bands using a tightly coupled PCML-SIR with a suitable impedance ratio. Then, a low impedance resonator is placed between the pair of PCML-SIR to generate multiple resonant frequencies for a broadband performance. The simulated and measured results of those filters agree very well. The bandwidth of the first band in the developed filters extends from 1.75 GHz to 3.75 GHz with less than 0.3 dB insertion loss at the center of the band. The second band has a bandwidth that extends from 6.95 GHz to 8.75 GHz with less than 0.5 dB insertion loss at the center of that band. The stopband separating those two passband has more than 30 dB attenuation with transmission zero at 5.85 GHz.
A Novel Microstrip Dual-band Bandpass Filter Using Dual-Mode Square Patch Resonators
Dual-mode square patch resonator is well known in the design of a single band quasi-elliptic bandpass filter response. Here, the dual-mode square patch resonator is employed to achieve a dualband bandpass filter. A 6 pole dual-band bandpass filter response with 3 poles at each passband will be presented. The dual-band filter also exhibits a transmission zero between the two passbands. A detailed discussion on the design procedure together with the simulation and experimental results will be presented.
A dual-mode dual-band bandpass filter using a single ring resonator
2009
A dual-mode dual-band bandpass filter is designed using a single stub-loaded slot ring resonator. This resonator is coupled to the two external feed lines at two positions spaced at 135 • along the slot ring through a pair of microstrip-slotline T-junctions. With a proper choice of the degree of external coupling, the first-order degenerate modes are split to make up the first passband with two transmission poles. The second passband is realized by the second-order degenerate modes, which are stimulated by symmetrically attaching four identical stubs along the slotring. The center frequency ratio of the two operating passbands is controlled by the nature and strength of the external coupling, which is determined by the characteristics of the microstrip open-circuited stubs. Finally, a dualband filter with center frequencies at 2.4 and 5.2 GHz is designed and fabricated. Measured results verify the design principle and predicted dual-passband performance. Benefiting from an additional transmission zero brought by the transitions,the upper stopband is expanded up to 12.75 GHz with at least 13 dB of rejection.
International Journal of Microwave and Wireless Technologies, 2011
In this paper a dual-band bandpass filter with sharp rejection is proposed. The filter is realized by using two half-wavelength stepped impedance resonators to operate at the passbands 2.5 and 3.5 GHz. To increase the band width further to about 45 MHz at the lower passband and 115 MHz at the higher passband, interdigital capacitors are introduced between resonator and input and output combining network. Measured insertion loss is about 1.45 and 1.7 dB at first and second passbands, respectively. A finite transmission zero in between two passbands at 2.84 GHz is realized to improve the selectivity of the filter. The design procedure to get highly selective response of the proposed filter is explicitly explained. An equivalent circuit model of proposed filter is developed that matches well with measured results.
A Novel Dual-Mode Wideband Band Pass Filter
─ A novel Wideband (WB) Bandpass Filter (BPF) with improved passband performance using a Defected Ground Structure (DGS) is presented in this paper. The proposed BPF is composed of two novel basic WB resonators and six Dumbbell-Shaped (DS) DGSs. By cascading resonators we can achieve better skirt characteristics, and by using DS-DGSs under interdigital coupled I/O lines we can improve the return loss within the passband. The simulated and measured results are found in good agreement with each other showing a wide passband from 4.93 to 11.62 GHz, a wide upper stopband with around 25 dB attenuation up to 20 GHz, and sharp roll-offs around 0.03 in lower and upper edges.