Low-loss Bandpass Research Articles

A Low-Loss Bandpass Filter With Stacked Double-Layer Structure Using Glass-Based Integrated Passive Device Technology

In this letter, a third-order low Insertion loss bandpass filter (BPF) is proposed by using a stacked double-layer structure through the technologies of the glass-based integrated passive device (IPD) and the through glass vias (TGVs). First, a stacked multi-layer structure was introduced to create a 3D-inductor of large inductance with a high Q factor. Then, an air cavity Metal-Insulator-Metal (MIM) structure was used to upgrade the Q factor of the capacitor. Therefore, a third-order low-loss small-sized bandpass filter can be generated by utilizing these LC elements of high Q factors. Experimental results show that the proposed BPF’s size and insertion loss is 0.018λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.013λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and 0.81 dB, respectively. In comparison with the existing design, the proposed BPF shows the superior advantages of smaller size and lower insertion loss.

Miniaturized Low-loss Band Pass Filter Based on Coupling Effect of Defective Structures for Ultra Broad Band Applications

Miniaturized Low-loss Band Pass Filter Based on Coupling Effect of Defective Structures for Ultra Broad Band Applications

Compact dual‐band bandpass filter with flexible passband frequencies and sharp skirt using cross coupling and mixed magnetic and electric coupling

This paper presents the design of a compact dual-band bandpass filter (DB-BPF) with flexible passband frequencies and sharp skirt. A pair of stub loaded stepped-impedance resonators (SL-SIRs) together with two different tri-section stepped-impedance resonators (TS-SIRs) constitute this DB-BPF. The low impedance sections of two SL-SIRs and one TS-SIR are realized by ring structure, on the one hand to acquire two independent resonant modes of SL-SIRs, and on the other hand to let the harmonic mode of TS-SIR be away from the upper passband. The cross coupling, the canceling effect of mixed electric and magnetic coupling (MEMC), and the virtual ground introduce the TZs, resulting in the sharp skirt property of proposed DB-BPF. Step-to-step design process is given to guide the DB-BPF design. As an example, a 0.9 / 1.8 GHz DB-BPF is designed and fabricated. The fabricated sharp skirts DB-BPF has a compact size of 0.079λg × 0.193λg, low passband loss of 0.84 / 0.98 dB and high band-to-band rejection of better than 40.6 dB.

Metamaterial-inspired multilayered structures optimized to enable wireless communications through a plasmasonic region

Radio frequency blackout is a well-known phenomenon that happens when a plasma forms around a plasmasonic vehicle traveling through an atmosphere. This paper examines an electromagnetic metamaterial-based approach to mitigate the communication losses through the blackout plasma. A paired epsilon- and mu-negative layered meta-structure is developed that is matched to the epsilon-negative plasma, creating a low-loss passband window through it. Its ideal performance is first characterized analytically. Metamaterial inclusions are then developed to attain the required single-negative layers. Numerical simulations of the resulting realizable meta-structure verify its efficacy, confirming the analytical results and the viability of using it to achieve reasonable signal strengths through representative plasma thicknesses.

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New low-loss tunable microstrip band-pass filter with two transmission zeros

In this paper, a low-loss tunable microstrip band-pass filter with two transmission zeros (TZs) around the pass-band edge is proposed. Making use of exactly same structure, three different fractional-bandwidth variations (i.e. constant fractional bandwidth, decreasing fractional bandwidth and increasing fractional bandwidth) can be realize by adjusting the amount of coupling between microstrip pairs. A prototype filter with constant fractional bandwidth is fabricated on a er = 3.38, 32 mil Rogers substrate. The center frequency of the fabricated filter is tuned from 770 to 1300 MHz by two varactor diodes. The constant relative bandwidth and insertion loss of the filter are 11 ± 0.2% and less than − 2.2 dB respectively. S-parameters and performance of the proposed filter are measured by Agilent VNA which show a good agreement with simulation results.

A Low-Loss Bandpass Filter using Edge-Coupled Resonator With Capacitive Feeding in (Bi)-CMOS Technology

In this Letter, a flexible approach for low-loss on-chip bandpass filter (BPF) design in CMOS technology is presented. The proposed approach takes the advantages of a combination of an edge-coupled electromagnetic structure, namely resonator, and a pair of metal–insulator–metal capacitors for BPF implementation. To demonstrate the insight of the approach, the designed resonator is analyzed in details by means of a simplified equivalent LC-circuit model. Then, the impact on the BPF design due to the variations of the feeding capacitance is investigated. To prove the concept, both the resonator and BPF are fabricated in a standard 0.13- $\mu \text{m}$ CMOS technology. The measured results show that the designed resonator can generate a notch with 20-dB attenuation at 59.4 GHz, while the BPF has a center frequency of 35.4 GHz with an insertion loss of 1.7 dB. The chip size of both devices, excluding the test pads, is only 0.039 mm2 ( $0.15 \times 0.26$ mm2).

Design of Compact Bandpass Filters Using Novel Dual-Mode Dielectric Patch Resonator

This paper introduces a new dual-mode dielectric patch resonator (DPR), which consists of a thin square dielectric patch with high permittivity and a low-permittivity substrate with bottom ground plane. A pair of TM11 degenerate modes can act as the dominate mode by fusing the dielectric patch and the substrate with the ground plane, whose resonant frequency is derived by using the combination of mixed magnetic wall method and mirror theory. It can be found that the constructed dual-mode DPR owns both merits of the planar transmission line and the dielectric resonator at the same time, i.e., low-profile configuration and high unloaded quality factor (Q u ). Based on the proposed dual-mode DPR, a single-ended bandpass filter (BPF) and a differential BPF is designed respectively. Good agreement can be observed between their respective simulated and measured results. Both of them showcase several advantages such as low passband loss, low profile, and compact size.

A Compact and Low-Loss Bandpass Filter Using Self-Coupled Folded-Line Resonator With Capacitive Feeding Technique

This letter proposes a compact and low-loss on-chip bandpass filter (BPF) design in (Bi)-CMOS technology. The proposed BPF consists of a self-coupled folded-line resonator and a pair of metal–insulator–metal capacitors. The proposed resonator has a property of flexible self-resonant frequency to form a transmission zero, which is analyzed in detail by a simplified LC equivalent circuit. Moreover, the parametric studies of the feeding capacitance for the proposed BPF design have been performed to demonstrate the tenability of the resonant frequency. For verification, the proposed BPF is fabricated in a standard 0.13- $\mu \text{m}$ (Bi)-CMOS technology. The measured results show that the proposed BPF has a notch with 25.4-dB suppression at 65 GHz and an insertion loss of 1.66 dB in the passband. The chip size of the device, excluding the test pads, is only 0.009 mm2 ( $0.11\times 0.086$ mm2).

High‐performance bandpass filter using HTCC stepped‐impedance resonators

Here, a novel rectangular bar stripline stepped-impedance resonator (SIR) using the multilayer high-temperature co-fired ceramic (HTCC) technology is constructed for designing a high-performance bandpass filter (BPF) with enhanced design flexibility. The properties of the HTCC SIR are investigated, so that its quality factor ( Q u ) can be improved. In the design process of comb-stripline filter, two transmission zeros (TZs) on both sides of the passband can be synthesised using the equivalent model for enhancing the passband selectivity. Thus, the resultant filter produced by the high dielectric constant material has several advantages, such as low passband loss, high selectivity, and compact size, which are verified by the simulation and measurement. In the demonstration of the fourth-order BPF centred at 2.25 GHz, two TZs are located at 2.05 and 2.54 GHz, showcasing a sharp roll-off. The insertion loss is <;1.8 dB in the passband. The BPF has a smaller size, when compared with the counterparts using other technologies. The occupied area of the BPF is 4.84 × 6.96 mm 2 .

Self-Packaged, Low-Loss, Planar Bandpass Filters for Millimeter-Wave Application Based on Printed Gap Waveguide Technology

A new concept of printed planar technology is introduced for the realization of low-loss bandpass filters in millimeter band. The new technology is self-packaged, and the insertion loss shows meaningful improvement compared to microstrip (MS) filters. The designs are based on the ridge gap waveguide (RGW), which is composed of printed parallel-plate waveguide surrounded by beds of mushrooms that suppress the signal around the waveguide. Several examples are designed, optimized, and measured. All-pole bandpass filters and filters with finite transmission zeros are proposed and studied. The performance of the proposed designs is compared to MS filters with different packaging options. In addition, an efficient transition from MS to printed RGW is designed and used in the circuits. The proposed circuits are low-cost and realizable using conventional printed circuit board technology. Measured results show good agreement with the analyses.

A compact low insertion loss bandpass filter based on meandered self-coupled ring resonator

The traditional structure of dual mode bandpass filter is formed by a circular or rectangular resonator, which causes excessive circuit areas to be occupied. A 5.2 GHz bandpass filter, based on the triple-branch self-coupled ring resonator, is designed to achieve most essential features such as low insertion loss, compact size, and wide stopband. The coupling of each coupled branch introduces the even- and odd-mode perturbation, which produce sharp bandpass and wide stopband responses due to the generation of band-edge transmission zeros. The simulation and measurement in this paper are respectively verified by using IE3D electromagnetic simulator and Agilent's HP8722C network analyzer. Experimental results show that the filter has 19.2% bandwidth centered at 5.2 GHz, 1.2 dB insertion loss, 25 dB stopband rejection from 6 to 9 GHz. Moreover, the circuit size in this paper has been down to 9×6 mm 2 and can be applied to communication of microwave applications.

A Fully Canonical Bandpass Filter Design Using Microstrip Transversal Resonator Array Configuration

This paper proposes a new and simple microstrip bandpass filter structure for the design of a fully canonical transversal array filter. The filter is constructed by the parallel arrangement of microstrip even-and odd-mode half-wavelength resonators. In this filter, transmission zeros (TZs) are not produced by cross couplings used in conventional filter designs, but by an intrinsic negative coupling of the odd-mode resonators having open ends with respect to the even-mode resonators with shorted ends. Thus, the control of the resonant frequency and the external Q factor of each resonator makes it possible to form both a specified passband and TZs. As an example, a fully canonical bandpass filter with 2-GHz center frequency, 6% bandwidth, and four TZs is synthesized with a coupling-matrix optimization, and its structural parameters are designed. The designed filter achieves a rapid roll-off and low-loss passband response, which can be confirmed numerically and experimentally.

Low-loss tunable tri-pole band-pass filter using crossed resonator

A low-loss tunable tri-pole band-pass filter is presented in this study. To achieve tri-pole response, the tri-mode crossed resonator is adopted in the design. Resonant property is analyzed based on the transmission line theory. Analysis reveals that the first three resonant frequencies and two inherent transmission zeros (TZs) of the proposed resonator can be tuned by the suitable loading capacitances. To decrease the passband insertion loss, the varactor diodes and dc block capacitors are in series connected between the feeds and resonator. Furthermore, to achieve high skirt selectivity, source-load coupling is also introduced to create a TZ near the lower edge of the passband. A demonstration tunable tri-pole filter is designed, fabricated, and measured. The measured results show that the new filter has the wide passband frequency tuning range of 33.3%, low insertion loss of less than 1.6 dB, and high selectivity.

Suspended stripline low‐loss bandpass filter with four transmission zeros

A novel fifth-order suspended stripline (SSL) low-loss bandpass filter with four transmission zeros is proposed. The technique of utilising only one cross-coupling structure introduces four transmission zeros to provide high selectivity. By adjusting the parameters of the coupling open loop, the performance of out-of-band of the filter can be changed. A detailed discussion of this effect of the coupling open loop is given. The highest out-of-band rejection of the filter is more than 70 dB. An SSL bandpass filter is designed, fabricated and measured. The measured results are in good agreement with the simulated results.

Design of Small-size and Low-loss LTCC Filters on Capacitively Loaded Cavities

Design of microwave filters for portable electronics is complicated by conflicting requirements to be met simultaneously such as high selectivity, low insertion loss and compact size. Substrate integrated waveguide (SIW) technology allows designing low-profile high-Q resonators and low-loss bandpass filters based thereof. However, SIW filters are not well-suited for telecommunication applications because of remarkably large size in plane. The size of a SIW cavity can be dramatically reduced by a capacitive loading. Capacitively loaded cavities (CLCs) operating in the TM110 mode can be as small as 1/8 of the guided wavelength and even smaller, i.e. comparable in size with lumped-element resonators. Although the unloaded Q-factor decreases proportionally to cavity size, miniaturized CLCs can exhibit much higher Q-factor than that of lumped-element resonators. This paves the way for designing small-size and low-loss filters for wireless communications and different applications. Miniaturized capacitively loaded SIW cavities are favorably implemented by means of the low temperature co-fired ceramics (LTCC) technology. The goal of the paper is to demonstrate manifold possibilities and flexibility offered by the LTCC technology to the design of advanced microwave filters on CLCs. Different design and manufacturing aspects are considered. Various design examples of high-performance LTCC resonators and filters for single- and dual-band wireless applications are presented. The designed resonators and filters were manufactured using the commercial DuPont Green Tape 951 LTCC system. The LTCC filters on miniaturized CLCs are shown advantageous with regard to small size, low loss, and absence of spurious response over a wide frequency range.

MNG 메타 인공 물질을 이용한 T-SRR 및 저손실 대역통과 필터의 설계

In this paper, the T-SRR (Triple Split Ring Resonator) using MNG (mu-Negative) meta-material adapted in a low-loss bandpass filter with 3-stages is suggested. The size of the T-SRR in the proposed bandpass filter with low dielectric constant PCB can be easily controlled. And the  transmission line theory is applied. The proposed T-SRR and filter have the center frequency of 10 GHz with QL value of 184 for military-satellite communication system in I band. The experimental results of the filter show that the insertion and return losses are 1.44 dB and 17.3 dB with bandwidth of 10 %, respectively. The proposed filter will be redesigned by IPD material etc. Abstract should be placed here. These instructions give you guidelines for preparing papers for JICCE.

Low-loss W-band CPW bandpass filter using annular CPW branch-line coupler with open load stubs

A W-band coplanar waveguide (CPW) low-loss annular branch-line bandpass filter for planar integrated millimeter-wave circuits is presented. It is designed by using the annular branch-line coupler as a transversal filtering section by loading the coupled ports of the coupler with suitable open load stubs and taking the isolated port as the output node. The proposed W-band bandpass filter shows very good performance, insertion-loss of 0.7 dB with a 14.9% of 3 dB relative bandwidth at center frequency of 94 GHz and return loss is better than −27 dB at the center frequency. The designed and fabricated bandpass filter exhibits the good performance for monolithic integrated millimeter-wave circuit applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2400–2403, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26264

Band-pass filters using high-permittivity ceramics substrate

The miniaturization of ring band-pass filters by employing high-permittivity ceramic substrates (with respective dielectric constants of 9.7 and 23.5) are investigated. Microwave dielectric ceramics with high-permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high-permittivity ceramics can be used as the substrate for band-pass filters. Moreover, the fundamental characteristics of newly developed compact ring resonators have also been described and applied to the design of band-pass filters. In this article, the designed ring resonators structures are simulated using an HFSS simulator. The responses of the fabricated band-pass filters using Al2O3 (εr = 9.7, tanδ = 0.0001) and 0.875Mg0.95Zn0.05TiO3-0.125Ca0.8Sm0.4/3TiO3 (εr = 23.5, tanδ = 0.000083) ceramic substrates are designed at the center frequency of 2.4 GHz. This compact size, low loss band-pass filter should be useful in many wireless communication systems. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2344–2347, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25439

Analysis and Design of a Chip Filter With Low Insertion Loss and Two Adjustable Transmission Zeros Using 0.18-$\mu{\hbox{m}}$ CMOS Technology

This paper presents the structure of a high-selectivity bandpass filter that is fabricated on low-resistivity silicon substrate with a commercial CMOS technology. The filter is constructed using crossed coplanar waveguide (CPW) lines and metal-insulator-metal capacitors to ensure that it has the desired passband characteristics. An adjustable capacitor between the input and output ports is employed to form a capacitive cross-coupled path, yielding two transmission zeros in the lower and upper stopbands, respectively. Additionally, the coupling mechanism can be modified by turning on or off the gate of an nMOS transistor to adjust the positions of the transmission zeros by applying an externally controlled voltage. To obtain a low passband loss and to minimize the chip size, high-impedance CPW transmission lines are adopted. Our analysis indicates that the CPW line possesses more advantages than the preferred stacked-ground CPW line for constructing the proposed filter. A very compact X -band experimental prototype with a size of 0.88 × 0.54 mm2 was designed and fabricated. The measurements reveal an insertion loss of less than 3.2 dB in the passband, which is from 10.6 to 12.7 GHz, and rejection levels greater than 35 dB at the designed frequencies of transmission zeros. Moreover, the lower and upper transmission zeros can be shifted from 5 to 6.5 GHz and from 18 to 21.4 GHz, respectively, by changing the controlled voltage.