Stepped-impedance Resonator Bandpass Filter Research Articles

Novel Stepped Impedance Microstrip Bandpass Filters for Radar Applications

In this paper, the design and realization of A Novel Microstrip Stepped Impedance Resonator Bandpass Filters with two selected center frequencies (f0) 12GHz and 16GHz presented. For The design of Band pass Filters “Rogers 6035HTC" substrate material with relative dielectric constant of 3.55, Standard thickness of 0.020” (0.508mm), thickness of pec is 0.035mm and simulated on High Frequency System Simulator (HFSS). Both the designed filters performances are discussed and compared with literature. The designed Stepped Impedance microstrip BPFs have insertion loss of <1dB with the optimal average performance of 37% and 32% FBW, and return losses are 47 dB and 32dB, which is reported better when compared with the reference designs.

Design and analysis of clover leaf‐shaped fractal antenna integrated with stepped impedance resonator for wireless applications

SummaryA novel multi‐band clover leaf‐shaped fractal antenna with integrated filtering to reduce higher order harmonics has been proposed. Existing microstrip filtering antennas endure limited gain, narrow impedance bandwidth, and undesired frequency radiations. The proposed antenna is designated to operate simultaneously in following operating bands: 3.35–3.6 GHz for WiMAX, 5.156–5.825 GHz for WLAN, 5.7–6.4 GHz for Intelligent Transport Systems (ITS), and 7.7–8.5 GHz for ITU‐R applications. The proposed patch is realized by combining two semi‐fractal ring microstrip patches like the geometry of a three‐leaf clover with dual‐layered stepped impedance resonator (SIR) integrated at bottom layer of the second substrate. The SIR bandpass filter exhibits odd and even modes suppresses higher order harmonics and undesired radiations. An aperture coupled feeding in the proposed patch offers better bandwidth and impedance matching. The number of iterations is increased to get the desired multiband characteristics. The proposed microstrip fractal antenna has the geometrical dimensions of 50 × 50 × 2 mm3. It is observed that both the simulated and measured results offers peak gain of >5 dBi and better return loss (S11), that is, 3.3–3.6‐GHz band offers S11 of −33.73 dB, 5.15–5.825‐GHz band offers S11 of −36.69 dB, and 5.795–6.4‐GHz band shows the S11 of −36.25 dB, and for 7.725–8.5 GHz, the return loss is −33.209 dB. Harmonics at 6.42 GHz (1.8f0), 7.37 GHz (1.5f0), and 9.04 GHz (1.73f0) has been suppressed and shows linear polarization in the WLAN band and circular polarization in the ITU‐R and WiMAX bands.

Design of dual-mode SIR bandpass filter based on shorting pin for wireless communication applications

<p id="docs-internal-guid-6a9909c3-7fff-4ac4-3e3a-a2f823e1246f" dir="ltr"><span>A new design of microstrip dual mode band-pass-filter (BPF) by using stepped impedance resonator (SIR) based on shorting pin is proposed. The designed structure use two U-shaped tri-sections SIR resonators coupled to each other and a two coupled line feeding ports each of 50 ohm impedance. Shorting pins are used to excite the upper frequency passband in the re sponse of the filter due to current distribution perturbation at the locations of the shorting pins. For demonstration, WLAN (5.2-5.7 GHz) and GSM (1.85-1.99 GHz) and Advanced Wireless Services (AWS) (1.71-1.755 GHz). The return losses are -32.469 dB and -26.18 dB respectively at the operating frequencies of the filter. The results of insertion losses of the filter is 0.37 and 0.24 dB during the operating bands and more than 25 dB which consider a good out-of- band rejection. </span></p>

A New Synthesis and Design Approach of a Complex Termination Impedance Bandpass Filter

A new synthesis for the design of a bandpass filter (BPF) with arbitrary real and/or complex termination impedances is presented in this paper. The proposed BPF can be terminated with arbitrary complex termination impedances simply by adding series transmission lines (TLs) to the first and the last coupled resonators. For design freedom, the characteristic impedances of the additional TLs can be chosen arbitrarily. Moreover, the proposed filter can be designed in either even- or odd-ordered stages using a $\lambda $ /4 stepped impedance resonator (SIR). For the validation of the proposed filter, two- and three-stage $\lambda $ /4 SIR BPFs with $Z_{S} = 30 + j10\,\,\Omega $ , $Z_{L} = 50 \,\,\Omega $ , and $Z_{S} = 50 \,\,\Omega $ , $Z_{L} = 100 + j100 \,\,\Omega $ , respectively, were designed and fabricated at the center frequency ( $f_{0}$ ) of 2.6 GHz. The measured results are consistent with the simulation results.

New Dual-/Tri-Band Bandpass Filters and Diplexer With Large Frequency Ratio

To satisfy the simultaneous requirements of future wireless communication systems on short-range high-speed data transmission and long-distance basic coverage, the coexistence of the millimeter-wave and microwave technologies becomes the inexorable trend. However, it is difficult for the existing dual-/ tri-band filter configurations to achieve a frequency ratio larger than three. In this paper, the new use of aperture coupling mechanism is proposed to combine two bandpass elements for dual-/tri-band operation with large frequency ratio but comparable sizes. For this purpose, a microwave BPF with wide stopband up to millimeter-waveband is implemented based on the complementary frequency response characteristics of the stepped-impedance resonator bandpass filter and low-pass filter. The millimeter-wave BPF can be simply designed using the air-filled substrate-integrated waveguide circular cavities, which exhibit the natural low-frequency cutoff characteristics. Based on the proposed design concept and two BPF elements, the dual-/ tri-band bandpass filters with frequency ratio up to 12.59 and 12.7 were designed, fabricated, and measured. Owing to the independence of the two elements, a diplexer with large frequency ratio can be simply implemented based on the previous dual-band filter. All the simulation and measured results are in good agreement, validating the proposed structures.

Wideband and Low-Loss High-Temperature Superconducting Bandpass Filter Based on Metamaterial Stepped-Impedance Resonator

This paper presents a wideband and low-loss high-temperature superconducting (HTS) bandpass filter (BPF) using a composite right/left-handed (CRLH) stepped-impedance resonator (SIR). The filter resonates at 2.6 GHz for LTE2600 application. The structure is designed in an entirely printed circuit technology based on the CRLH theory and its equivalent circuit. For the same center frequency, fractional bandwidth and stop-band attenuation, the presented CRLH SIR BPF proves to surpass its conventional counterpart in terms of size without degradation in performance. The CRLH SIR BPF is also significantly more controllable in its dimensions and response due to the fact that more elementary parameters are available in the CRLH configuration. The proposed filter is simulated and measured, and the measurement results match well with the simulation results. Good properties of low in-band insertion loss, good out-band rejection, and compact size have been achieved and verified. Intermodulation distortion (IMD) and the transmission properties at different temperatures are used to investigate the nonlinearity of the HTS filter. IMD can also clarify the power-handling capability of the filter.

A coupled line bandpass filter using a novel SIR with intentional coupled length

ABSTRACTA novel stepped impedance resonator (SIR) and its design formulas for the coupled line bandpass filter (BPF) are proposed. The proposed SIR can provide tight coupling by intentionally extending the length of a coupled line. In addition, it forms the second passband much farther away compared to the conventional SIR. To show the validity of the proposed SIR and its application to the coupled line BPF, the three‐pole SIR BPF is designed and fabricated. The measured and simulated results are in very good agreement. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1259–1262, 2015

Miniaturized Composite Right/Left-Handed Stepped-Impedance Resonator Bandpass Filter

In this letter, a microstrip Stepped Impedance Resonator (SIR) bandpass filter (BPF) based on Composite Right/Left-Handed (CRLH) transmission lines is presented for the first time. Supported by theory, full-wave simulations and measurements, operational principle of the filter is explained and results are analysed. Also, comparison is made between this filter and its conventional right-handed (RH) counterpart. For the same centre frequency, fractional bandwidth and stop-band attenuation, the CRLH SIR BPF presented here proves to surpass its conventional counterpart in terms of size, being about 80% smaller, without degradation of performance. The CRLH SIR BPF is also significantly more controllable in its dimensions and response due to the fact that more elementary parameters are available in CRLH configuration.

Miniature bandpass filters with stepped‐impedance resonators

AbstractIn this article, a new configuration of higher selectivity bandpass filter using miniature open‐loop stepped‐impedance resonator (SIR) is designed and fabricated. The central frequency of the filter is 2.45 GHz and the bandwidth is 8%. Using miniature open‐loop SIR resonator, we design filter based on cross‐coupling and input and output external quality factor. A single transmission zero is realized by the cross‐coupling in the structures, which can improve the skirt selectivity of the filter. The circuit size of a miniature open‐loop SIR bandpass filter reduces to 50% of the square open‐loop resonator bandpass filter. The results of measurements are in good agreement with the full‐wave simulation results. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1167–1170, 2012

Design of cross-coupled stepped-impedance resonator bandpass filter using low-temperature cofired ceramic technology

A novel compact half-wavelength cross-coupled stepped-impedance resonator filter using low-temperature cofired ceramic (LTCC) technology is presented. The filter not only has good selectivity due to the controllable transmission zeros but also has a small size by the virtue of LTCC structure. Based on the theory of cross-coupled stepped-impedance resonators and 0° feed structure, a bandpass filter with the center frequency of 1.25 GHz has been designed and fabricated. Good agreement between measured and simulated results is observed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2201–2204, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26243

Method of determining feed positions in coupled half-wavelength stepped impedance resonator bandpass filter

In this study, the input impedance of coupled half wavelength stepped impedance resonator bandpass filter with directly tapped feed structure is deduced, and the method of determining the feed positions in the filter is proposed by using the concept of impedance matching. Two microstrip bandpass filter examples are described for demonstrating the procedure. The simulated and measured results indicate that the proposed method is an effective way for designing similar filters.

A compact pseudo-interdigital SIR bandpass filter with improved stopband performance

A pseudo-interdigital stepped impedance resonator (SIR) bandpass filter (BPF) using tapped I/O is designed and fabricated. By using a pseudo-interdigital structure and the SIR, the proposed BPF gains advantages of compactness and high selectivity. In this paper, the first and second spurious responses are shifted to higher than 3f0 (the designed center frequency) due to the SIR effect and the effect of using the tapped I/O, and fast passband-edge attenuation is obtained as a result of the transmission zeros in the passband edge created by interstage coupling. The experimental results of the fabricated filter show good agreement with the simulation results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 462–464, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21200

Stepped impedance resonator bandpass filters using tapped‐line for controlling spurious response

AbstractA stepped impedance resonator bandpass filter was designed and implemented, combining with the tapped‐line structure. The measured bandpass filters at the center frequency of 2.0 GHz has the characteristics: the insertion loss S21 = −2.98 dB, BWR is 15.1%, and the transmission zeros occurred at 2.62 GHz with −48.5 dB. Especially, the wider rejection of −20 dB can be obtained form 2.4 to 8.2 GHz from the proper position of tapped‐line I/O. The designed filter shows the excellent abilities to shift and suppress the spurious response by properly designing the structure of the resonator. The proposed filter was designed and fabricated, and the performances closely matched the simulation results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 481–484, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20010

Microstrip stepped impedance resonator bandpass filter with an extended optimal rejection bandwidth

Bandpass filters with an optimal rejection bandwidth are designed using parallel-coupled stepped impedance resonators (SIRs). The fundamental (f/sub o/) and higher order resonant harmonics of an SIR are analyzed against the length ratio of the high-Z and low-Z segments. It is found that an optimal length ratio can be obtained for each high-Z to low-Z impedance ratio to maximize the upper rejection bandwidth. A tapped-line input/output structure is exploited to create two extra transmission zeros in the stopband. The singly loaded Q(Q/sub si/) of a tapped SIR is derived. With the aid of Q/sub si/, the two zeros can be independently tuned over a wide frequency range. When the positions of the two zeros are purposely located at the two leading higher order harmonics, the upper rejection band can be greatly extended. Chebyshev bandpass filters with spurious resonances up to 4.4f/sub o/, 6.5f/sub o/, and 8.2f/sub o/ are fabricated and measured to demonstrate the idea.