Compact Dual-Band Bandpass Filter Based on Stub-Loaded Rectangular Loop Stepped Impedance Resonator (original) (raw)
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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.
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.
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).
A compact microstrip dual-wideband bandpass filter using ladder stub resonator
Microwave and Optical Technology Letters, 2009
In this article, we present a novel compact dual wideband bandpass filter (BPF) by using a new structure of ladder stub resonator (LSR). The proposed LSR can produce attenuation poles to form low loss and dual-wideband bandpass response. By tuning the structure parameters of LSR, the dual-band characteristic can be controlled. The measured 3 dB fractional bandwidth (FBW) at first and second passbands are 41.5% and 25.7%, respectively. The experiment results of the fabricated filter agree well with the electromagnetic (EM) simulation. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1391–1393, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24392
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.
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.
Microwave and Optical Technology Letters, 2009
used in the circuit simulation. Figure 4 shows comparison between the EM-simulated, circuit-simulated, and measured performances of the ring-like resonators with (a) W ϭ 0.2 mm (150 ⍀) and (b) W ϭ 8 mm (20 ⍀). It is clearly observed that the EM-simulated, circuit-simulated and measured performances are matched closely for the ring resonator with W ϭ 0.2 mm. However, when W ϭ 8 mm, the circuit-simulated frequency is slightly higher than EMsimulated and measured frequency. The difference between the EM-simulated and circuit-simulated performance becomes larger when the width of the ring increases, indicating the proposed analyzed technique using the transmission-line analysis is not suitable for the patch resonator. However the difference is 6% even the width and impedance are so different for W ϭ 0.2 mm (150 ⍀) and W ϭ 8 mm (20 ⍀). The result indicates the analyzed technique using the transmission-line analysis is workable for most of the ring-like resonators. Moreover, the equivalent circuit model of the microstrip ring resonator with different widths have been investigated, thus performance o the ring-like resonator can be predicted when integrating with the other active devices on the same substrate to be RF-SOC. 4. CONCLUSIONS In this article, we used the simple parallel GLC lumped element circuit to model the equivalent circuit of the ring-like resonator with different impedance and then investigated the equivalent lumped elements. An analyzed technique using the transmissionline analysis is presented in this article, with help of the EM simulator. It is found that the circuit simulated results from the extracted element values are in good agreement with the full-wave simulation results and the measured results. The result indicates the analyzed technique using the transmission-line analysis is workable for most of the ring-like resonators.
Journal of Telecommunication, Electronic and Computer Engineering, 2017
This paper presented a design to realize a compact dual-band bandpass filter using a pair of coupled symmetric stepped impedance resonator (SIRs) and U-shaped microstrip structure for wireless communication applications. To obtain its compact size, the symmetric SIR was bent like an L-shape. The U-shaped microstrip structure was designed and integrated into the SIR to achieve notch bandstop response so as to produce the specified dual-band bandpass filter. For the resonant frequency and attenuation, the U-shaped microstrip structure was designed at 3GHz and greater than 60dB respectively. Based on the simulation and experimental results, it was verified that this proposed design produced two passbands centered at 2.5GHz and 3.5GHz with the fractional bandwidth of more than 16%. The return loss and insertion loss are better than 15dB and 1dB respectively. The simulated and measured results are both presented and showed a good agreement. This proposed dualband bandpass filter is benef...