Compact tapped stepped impedance open stub dual‐band bandstop filters with sharp rejection characteristics (original) (raw)
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Compact dual-wideband bandstop filter using a stub-enclosed stepped-impedance resonator
AEU - International Journal of Electronics and Communications, 2016
A compact, wide dual-band bandstop filter (DBBSF) based on a stub-enclosed stepped-impedance resonator (SE-SIR) is proposed. The second order filter is employed to obtain two transmission zeros in each stopband for better selectivity. The proportional tuning of both center frequencies is achieved by proportionately varying the electrical length of the enclosing stub with that of the high impedance section of the stepped-impedance resonator. Additionally, the second center frequency is tuned independently only by varying the electrical length of the enclosing stub. Two center frequencies at 4.7 and 6.64 GHz are reported, corresponding to the rejection of 35.1 and 26.23 dB and the fractional bandwidth of 31.02 and 23.93%, respectively at −3 dB. The size of the proposed filter is achieved to be 0.38 g × 0.07 g. The experimental results demonstrate its potential application in C-band communication systems.
Compact dual-band open-stub bandstop filter with suppression of spurious passbands
In this article, by replacing the series quarter-wavelength connecting line of conventional open-stub bandstop filter (BSF) with the equivalent P-shaped line, a compact dual-band BSF is proposed and designed. Furthermore, it suppresses a lot of spurious passbands of the open-stub BSF. Design equations of P-shaped line are achieved by ABCD matrixes. To validate the design concept, two full-wave electromagnetic simulators are used and the proposed filter is fabricated. The simulate results are in excellent agreement with measurement results. The circuit area of the dual-band BSF is only 50% of the conventional open-stub BSF.
International Journal of Microwave and Wireless Technologies, 2016
bukuru denis, kaijun song and fan zhang A compact dual-band bandpass filter using stub-loaded stepped impedance resonator (SLSIR) with cross-slots is presented. The symmetric SLSIR is analyzed using even-and odd-mode techniques. Design equations are derived and they are used to guide the design of the circuits. Two passbands can be easily tuned by cross-slots and open stubs. Transmission zeros among each passbands are created, resulting in high isolation and frequency selectivity. An experimental circuit is fabricated and evaluated to validate the design concept. The fabricated filter is compact with 19.76 × 12.7 mm 2. The measurement results are in good agreement with the full-wave simulation results.
Design of Triband Bandstop Filters Using a Stub-Loaded Stepped-Impedance Resonator
Progress In Electromagnetics Research Letters
A stub-loaded stepped-impedance resonator is proposed. Its input impedance is derived, and its resonant conditions are found. First order and second order triband bandstop filters are designed using this resonator. Simulations on both filters show that they generate three attenuation poles at 0.5, 1.2, and 2.1 GHz. The second order filter is also fabricated and characterized using a microwave vector network analyzer. Simulation and measurement results on the second order filter show good correlation.
Compact Dual-Band Bandpass Filter Based on Stub-Loaded Rectangular Loop Stepped Impedance Resonator
International Journal of Electromagnetics (IJEL)
This work presents a compact dual-band bandpass filter (BPF) based on stub-loaded rectangular loop stepped impedance resonator (SLRLSIR). The proposed SLRLSIR consists of two outer open-circuited and two inner open-circuited stubs, which are designed to the central sides of the rectangular loop resonator. Owing to its symmetry, even-and odd-mode analysis methods are applied to deduce the equivalent-circuit equations and to justify the structural design. The second passband can be easily tuned by changing the two inner open-circuited stubs when the first passband is fixed at a desirable frequency. The upper stopband is improved by a pair of additional open-circuited stubs stepped impedance resonators at the I/O ports. Transmission zeros are generated between passbands and stopbands. A SLRLSIR prototype dual-band BPF with central frequencies of 2.42/4 GHz is fabricated and systematically studied. The measurement results agreed well with the simulation results.
Bandpass and bandstop filters based on open stubs with ground plane slots
Microwave and Optical Technology Letters, 2012
This work reports on a modified version of k/2 open stubs bandpass filters (k/2-OSBPFs) and k/4 open stubs bandstop filters (k/4-OSBSFs) for wide/narrow bandwidth operation. When wide bandwidths (for k/2-OSBPF) or narrow bandwidths (for k/4-OSBSF) are required, conventional microstrip implementation of this kind of filters is not possible owing to unattainable high stub characteristic impedance values, which lead to extremely narrow strips. To overcome this drawback, we propose the introduction of slots under the stubs along the grounded backside of the substrate. This provides additional flexibility for the width of the strips printed on the upper side of the substrate, which can be much wider than without the slots. To avoid undesired resonances of the slot mode and radiation problems, printed narrow strip short circuits are distributed along the slotted regions. It is shown that the presence of these strips does not meaningfully affect the filter performance while suppresses the undesired slot mode effects.
A novel compact quad-band microstrip bandstop filter design using open-circuited stubs
2013 IEEE MTT-S International Microwave Symposium Digest (MTT), 2013
A novel compact quad-band microstrip bandstop filter design is presented. Input and output ports of the filter are connected with a high impedance transmission line. Proposed filter is designed by using open-circuited stubs attached to the input and output ports. Thus, based on the f r-3f r harmonic property of the stub-loaded resonators, four stopbands at 1.15-2.22, 2.94-4.56, 4.95-6.98 and 8.26-8.96 GHz are obtained. Insertion losses of all stopbands are better than 15 dB inside the stopbands. Under the even and odd mode excitations, resonance conditions of the structure are also investigated. For the experimental verification of the simulated results, proposed filter has been fabricated. Simulated and measured results are in a good agreement. Index Terms-Bandstop, quad-band, open-circuited stubs.
Small Size Dual-Band Bandpass Filters with Multiconductor Transmission Lines and Shunt Open Stubs
2018 48th European Microwave Conference (EuMC), 2018
A dual-band bandpass filter consisting of multiconductor transmission lines (MTL) and shunt stubs has been designed. The used topology, based on the interconnection of two identical MTL and a shunt open stub, has a frequency response that can be modelled by using the generalized Chebyshev functions. A prototype of a 4 fingers-MTL is manufactured and measured and a good agreement between analytical and measured results is obtained. Furthermore, it is easy to get a design criterion that enables getting good responses varying just a few parameters.
APPLICATION OF STUB LOADED FOLDED STEPPED IMPEDANCE RESONATORS TO DUAL BAND FILTERS
Progress In Electromagnetics Research, 2010
In this paper, a folded stepped impedance resonator (SIR), modified by adding an inner quasi-lumped SIR stub, is used as a basis block for a new implementation of dual-band bandpass filters. The main advantage of the proposed filter is to make it possible to independently control the electrical features of the first and second bands. The behavior of the first band basically depends on the geometry of the outer folded SIR. The second band, however, is strongly influenced by the presence of the inner stub. Additional design flexibility is achieved by allowing the inner stub to be located at an arbitrary position along the high impedance line section of the main SIR. The position of the tapped input and output lines can be Corresponding author: M. D. C. Velázquez-Ahumada (velazquez@us.es).