APPLICATION OF STUB LOADED FOLDED STEPPED IMPEDANCE RESONATORS TO DUAL BAND FILTERS (original) (raw)
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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.
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.
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.
Miniaturized dual-band bandpass filter based on stepped impedance resonators
Microwave and Optical Technology Letters, 2017
In this article, we developed a dual-band band-pass filter (DB-BPF) based on stepped impedance resonators (SIRs) using coupled feeding lines input and output ports. The developed filter allows the adjustment of the frequency and the bandwidth of the upper band (3.8 GHz) and the lower band (2.4 GHz). The transmission coefficients of the DB-BPF are improved by maximizing the coupling between the SIRs. Furthermore, the capability of the rejection band is increased and the insertion losses between the two pass-bands are reduced. The experimental results for the insertion loss (S 21) and the return loss (S 11) of the lower band (2.4 GHz) were1.0 and 2.0 dB, respectively while the insertion loss and return loss for the upper band (3.8 GHz) were 23 and 25 dB, respectively. The 3 dB fractional bandwidths obtained for both bands were about 200 MHz and four transmission zeros around the passband edges were created to improve the selectivity of the DB-BPF. The overall size of the DB-BPF was also reduced significantly.
Compact multilayer dual-band filter using slot coupled stepped-impedance-resonators structure
Microwave and Optical Technology Letters, 2009
In this article, a new miniaturized configuration of singleinput-single-output dual-band bandpass filter operating at ISM 2.45 GHz and UNII 5.8 GHz frequency bands using a multilayer structure with stepped-impedance resonators is presented. A coupling aperture is introduced in a common ground to ensure the coupling between the two resonators located in the upper layer and the lower one. The use of stepped-impedance resonators allows tuning the two bands at desired frequencies. Finally, a design prototype was fabricated to validate the proposed concept. The insertion loss and return loss at the central frequency are Ϫ1.35 dB and Ϫ17 dB for 2.45 GHz band, and Ϫ0.98 dB and Ϫ13 dB for the 5.8 GHz band, respectively. There is a good agreement between experimental and full-wave electromagnetic simulation results.
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.
Multiband Bandpass Filter (BPF) based on Folded Dual Crossed Open Stubs
International Journal of Technology, 2014
A compact multiband bandpass filter (BPF) based on folded dual crossed open stubs (DCOS) is designed and analyzed. Two Crossed Open Stubs (COS) are used to generate concurrent sixband BPF, where the center frequency located at 0.95 GHz, 1.85 GHz, 2.65 GHz, 3.35 GHz, 4.375 GHz, and 5.25 GHz. The proposed BPF based on folded Dual Crossed Open Stubs (DCOS) is an expansion of tri-band BPF based on a single COS, where the second COS is used to generate second additional tri-band. To achieve miniaturization structure of proposed BPF, the DCOS is folded. The proposed BPF will be designed and analyzed by using Advanced System Design (ADS). The performances of multiband BPF which characterized by return loss, insertion loss, voltage standing wave ratio (VSWR), and group delay, are conducted by simulation, measurement and analysis. It is shown that the simulation and fabrication results of insertion loss, return loss, VSWR, and group delay of the proposed multiband BPF are satisfied to design requirements. However, the center frequencies of fabricated the proposed multiband BPF are shifted average to 530 MHz lead to simulated results. This is due to some errors in fabricated process including imperfect dimension of fabricated BPF, soldering between connector to substrate and cable losses.
Microwave and Optical …, 2009
In this article, a novel transmission line (TL) shunt stepped impedance open stub configuration has been presented to design a dual-band bandstop filter with impedance controlled center frequencies and bandwidths. Design guidelines are derived using lossless TL model. The high-impedance lines required for TL sections facilitate convenient meandering that makes the geometry compact. To validate theoretical predictions, a prototype filter operating at two bands 1.5 and 3.4 GHz has been fabricated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2274–2277, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24635
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.