Microstrip Dual-mode Resonator Research Articles

A novel compact microstrip dual-band bandpass filter with independently controlled center frequencies based on dual-mode resonators concept

This letter presents a novel ultra-compact microstrip dual-band bandpass filter (DBBPF) with independently controlled center frequencies, and high Q-factor. The recommended DBBPF is realized by combining two different microstrip dual-mode resonators. One is a short-end stub-loaded resonator used to produce the first passband and the other one is an open-end stub-loaded resonator operating at the second passband which serves as part of the feed lines for the lower passband. To validate the performance of the proposed configuration, a novel compact DBBPF with center passband frequencies of 2.4 and 3.55 GHz is designed, simulated, fabricated and tested. A good agreement has been found between the simulation and measurement results. The designed microstrip DBBPF occupies a small area which is only about 0.19 λg × 0.15 λg. The presented microstrip DBBPF has many advantages in terms of compact size, low insertion loss, good frequency selectivity, easy fabrication, and high selectivity.

Miniaturized Quarter-Mode SIW Filters Loaded by Dual-Mode Microstrip Resonator With High Selectivity and Flexible Response

A novel miniaturized multilayer quarter-mode substrate integrated waveguide (QMSIW) filter with high selectivity and wide stopband is proposed. First, an innovative multilayer dual-mode microstrip resonator is proposed to couple the QMSIW resonators located at the upper and lower substrate layers. The combination of the dual-mode resonator with the two QMSIW cavities leads to a fourth-order filtering response. Then, the coupling iris is opened at the position, where the magnetic field distribution in the QMSIW cavity achieves a peak value. Finally, sharp skirt is obtained by composing the modified box-like topology. In addition, different responses could be achieved by changing the position of the coupling iris, resulting in a wide stopband and flexible response. The size of the filter is also reduced through the multilayer QMSIW configuration and miniaturized multilayer dual-mode microstrip resonator.

8-order filter based on 2-D photonic crystal with dual-mode microstrip resonators

The design of 8-order band-pass filter based on 2-D photonic crystal is suggested. Strip conductors in all dual-mode resonators are in the form of «irregular» rectangular frame with a gap and are connected at certain points with the ground. At optimal placement of such resonators on a substrate attenuation pole is observed on the amplitude-frequency characteristic of the filter, near low and high bandwidth slope that significantly improves its frequency-selective properties. The change of gap between input and output resonators allows to control the frequency of these poles.

Design of Dual-Mode Dual-Band Superconducting Filters

This paper presents a synthesis design method for superconducting dual-mode dual-band filters. A low-pass to dual-band bandpass frequency transformation is proposed based on lossless lumped-element dual-mode resonator circuits. Formulas for extracting the coupling coefficient $k$ and external quality factor $Q_e$ of dual-mode microstrip resonators are derived using the coupling matrix theory and the proposed frequency transformation formula. This makes the design process of dual-mode dual-band filters similar to that of the single bandpass filter. For the demonstration, four dual-band superconducting filters with different dual-mode resonator structures, such as stepped-impedance, stub-loaded, and embedded resonators are designed and fabricated. The measured results match well with the simulations.

Planar dual-mode dual-band bandpass filter using a modified rectangular split-loop resonator loaded by an open-circuited stub

A compact planar dual-band bandpass filter using a new microstrip dual-mode resonator has been proposed in this article, which is based on a modified rectangular split-loop resonator loaded by an open-circuited stub. The implemented filter with two passbands has shown an excellent performance, including three transmission zeros disturbed nearby the two passband edges and between the passbands, by which a high selectivity is obtained for the proposed filter. Also, the measured results agree well with the simulated ones.

Compact substrate integrated waveguide transversal filter with mixed source–load coupling

This study proposes a compact implementation of substrate integrated waveguide (SIW) transversal filter with mixed source and load coupling. One dual-mode microstrip resonator, etched on the top metal layer of SIW cavity, is utilized to achieve transversal topology. Therefore, four transmission zeros can be obtained by introducing mixed sourced and load coupling, which is realized by inter-digital slot structure. A third-order SIW transversal filter sample is fabricated using printed circuit board technology, and its measured S-parameters have good agreements with the simulated ones.

BAND-NOTCHED ULTRA-WIDEBAND BANDPASS FILTER USING DUAL-MODE RESONATOR LOADED SLOTLINE

In this article, a novel band-notched ultra-wideband (UWB) bandpass fllter based on hybrid microstrip/slotline structure is proposed. A quad-mode stubs-loaded slotline resonator is fed by two orthogonal microstrip lines and ultra-wideband bandpass characteristic is excited. A stub-loaded dual- mode microstrip resonator is externally loaded to the quad-mode slotline resonator, and a notched band with sharp roll-ofi characteristic is achieved. The circuit model for the dual-mode microstrip resonator loaded slotline is given and analyzed. The proposed fllter is designed and fabricated. Simulated and measured return losses are i12dB/i18dB and i18dB/i10dB in lower and higher passband. The return loss in the notched band is greater than 15dB.

A novel compact configuration for dual-mode microstrip resonators and dual-band bandpass filter applications

In this article, a novel compact dual-mode resonator formed by a square loop having folded arms and mitered bends is proposed.Degenerate modes can be excited by shifting the gaps between the folds. Thus, the center frequency can be arranged at a fixed value because the total electrical length of the proposed configuration is not changed. A novel compact dual-mode dual-band bandpass filter is also designed by locating the one resonator within the other. Additionally, to suppress the harmonic of the first passband, open-circuited stubs are connected to the end of the feedlines. Two dual-mode dual-band bandpass filters with the elliptical and linear phase filtering characteristics for both passbands have been designed, fabricated, and tested. Calculated, simulated, and measured results are in a good agreement. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:775–779, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27444

A miniature dual-band filter based on microstrip dual-mode resonators

A microstrip dual-band bandpass filter (DBF) with an original miniature design is described. The filter consists of thee microstrip dual-mode resonators, which are rendered dual-mode by splitting their regular strip conductors from one end by longitudinal slots. The formation of one passband of the DBF involves the resonances of even modes of each microstrip double-mode resonator, while the other passband is formed by the resonances of odd modes. The proposed device is simple to manufacture and allows the central frequencies and widths of each passband to be tuned within broad limits. A method of DBF tuning has been developed. Good prospects of the proposed microstrip DBF are confirmed by the high characteristics of its working prototype.

COMPACT HALF-MODE SUBSTRATE INTEGRATED WAVEGUIDE (HMSIW) FILTER WITH DUAL-MODE MICROSTRIP RESONATOR

Abstract—A novel fourth-order half-mode substrate integrated waveguide (HMSIW) filter with dual-mode microstrip resonator is presented. The dual-mode resonator is etched on the top metal layer of HMSIW cavity, so the size can be reduced greatly. The filter has compact size and wide stopband in comparison with conventional SIW filters. Microstrip resonators and cavity resonators are integrated in one filter to achieve the goal of smaller size and better performance. Two filter samples are designed and fabricated, with good agreement between the measured and the simulated S-parameters.

A compact microstrip dual-mode filter

A novel structure of a compact microstrip dual-mode resonator is proposed for a dual-mode filter application.The proposed dual-mode resonator is miniaturized using an interdigital capacitor and stepped impedance structure. In addition, the proposed dual-mode resonator provides two transmission zeros in the stopband. The dual-mode filter application is designed for 2.4 GHz wireless local area network (WLAN) with three transmission zeros. An additional transmission zero is generated in the filter application using a cross coupling capacitor between input/output ports. Experimental measurements are also presented to validate the theory. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2368–2371, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26279

DUAL-MODE SPLIT MICROSTRIP RESONATOR FOR COMPACT NARROWBAND BANDPASS FILTERS

A straight split dual-mode microstrip resonator is proposed. The frequencies of the two flrst oscillation modes in the resonator may be brought closer together by adjusting a split parameter whereas the frequency of the third mode remains approximately equal to the doubled average frequency of the flrst and the second modes. It is shown that formulas derived within 1D model give qualitatively true relations between the resonant frequencies and the structure parameters of the resonator. Examples of narrowband bandpass fllters of the fourth and the sixth order are described. Transmission zeros below and above the passband substantially improve the fllter's performance. The simulated frequency response of the three-resonator dual-mode fllter is compared with the measured response of the fabricated fllter.

Harmonic-rejected compact bandpass filter using dual-mode microstrip resonator with additional open stub

In this article, a compact dual-mode λg/2 bandpass filter with the characteristic of harmonic rejection is designed and implemented.The second and third harmonics of the suggested bandpass filter are rejected by using the additional open stubs of the T-type equivalent circuit for the quarter wavelength line. Also, the J-inverter is investigated as functions of the impedance and electrical length of the open stub of dual-mode λg/2 resonator. From the results, the lower impedance of open stub of dual-mode λg/2 resonator is better for the good performance of the dual-mode λg/2 bandpass filter. The harmonic-rejected dual-mode λg/2 bandpass filter shows the characteristic of suppression of harmonics until 8 GHz and the insertion and return losses of 0.96 and 18.89 dB, respectively, at the center frequency of 2.43 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2288–2291, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25457

Compact Substrate Integrated Waveguide Transversal Filter with Microstrip Dual-Mode Resonator

A compact substrate integrated waveguide (SIW) transversal filter using microstrip dual-mode resonator is proposed, with its coupling scheme given to predict its desired performance. The microstrip dual-mode resonator is introduced to achieve compact size, which is etched on the top metal layer of the SIW cavity. An additional transmission zero, contributed by bypass coupling due to the higher order mode of SIW cavity, is used to suppress its first spurious passband. A filter sample was fabricated using standard printed circuit board (PCB) technology, with good agreements obtained between its measured and simulated S–parameters.

EXTENDED DOUBLET BANDPASS FILTERS IMPLEMENTED WITH MICROSTRIP RESONATOR AND FULL-/HALF-MODE SUBSTRATE INTEGRATED CAVITIES

Two extended doublet bandpass fllters with compact size and good spurious suppression characteristic are proposed. One is built up by a dual-mode microstrip resonator with a full-mode substrate integrated cavity, while the other is composed of a microstrip resonator and a half-mode cavity. The relationship between the location of their transmission zeros and the impedance ratio of the microstrip resonator is analyzed theoretically. Our proposed fllters only occupy the areas of 0:69‚ 2 =r and 0:51‚ 2 =r, and they also have wide upper stopband. The predicted performances are demonstrated by the reasonable agreement obtained between their simulated and measured S-parameters.

Compact Dual-Mode Open Loop Microstrip Resonators and Filters

A novel compact microstrip dual-mode resonator and filter are proposed. The characteristics of the dual mode resonator are investigated. It is found that the filter response exhibits a desirable stopband response where the first spurious passband naturally occurs at 3f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Finally, methods of miniaturizing such resonators and filters are discussed. The proposed structure was able to achieve 60% size reduction.

Dual-mode microstrip filters with adjustable transmission zeros

A new type of dual-mode microstrip square-loop resonator that produces asymmetrical frequency responses is proposed. The coupling between degenerate modes of the proposed dual-mode resonator is discussed depending on the perturbation size. The effect of non-orthogonal input/output feed lines located along a straight line on the frequency response is investigated using full-wave electromagnetic simulations. Two second-order bandpass filters using this type of dual-mode microstrip resonator are designed, fabricated and measured to demonstrate the dual-mode microstrip filters exhibiting transmission zero (TZ) shifting property. The one of the second-order filters produces a filter characteristic with two TZs in the upper stopband, whereas the other one has two TZs in the lower and upper stopbands. The shifting property of one of the TZs from one side of the passband to the other side is realised by only changing the perturbation size. The fourth-order filters of this type are also investigated. Both simulated and measured results are presented.

Performance improvement and size reduction of microstrip dual-mode bandpass filter

A novel miniaturised dual-mode bandpass filter with multi-arc resonators is proposed. The size of the dual-mode filter can be reduced significantly by using the microstrip dual-mode resonator consisting of multi-arcs; meanwhile insertion loss and spurious response suppression are improved. A prototype filter is designed and implemented at 3.6 GHz with 2.8% fractional bandwidth, which shows a low passband insertion loss of 1.02 dB and a wide stopband with rejection better than 20 dB up to about 8.5 GHz.

Miniature Dual-Mode Microstrip Filters

In order to reduce the size of dual-mode microstrip filters by keeping excellent performance, novel filter geometry is proposed. The novel filter includes a dual-mode resonator based on a meander structure. The effect of input/output feed lines located along a straight line on filter response is investigated for the dual-mode filter. The coupling between degenerate modes of the proposed dual-mode microstrip resonator is discussed depending on the perturbation size. The two dual-mode microstrip bandpass filters with real axis and imaginary axis transmission zeros (TZs) are designed, fabricated, and measured to document the validity of the description of the positive and negative coupling coefficient

Dual-Mode Reconfigurable Filter With Asymmetrical Transmission Zeros and Center Frequency Control

A reconfigurable bandpass filter with asymmetrical responses is demonstrated using a dual-mode microstrip resonator. The proposed topology introduces several fixed and switchable perturbations to control the center frequency and the location of the transmission zeros of the filter. The tuning mechanism consists of capacitively loading the edges of a modified square patch resonator, in order to manipulate the current distribution of the degenerate modes. This operation results in asymmetrical responses with a center frequency tuning ratio of 10% at X band, and angular transmission zero displacement of Deltaomega <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">z </sub> = 3.5rad/s or greater in both a lower and higher side of the passband