Low-loss Bandpass Filter 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.

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).

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).

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.

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

Microstrip ring resonator bandpass filters using ceramic substrate

AbstractThe miniaturization of ring bandpass 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 bandpass filters. Moreover, the fundamental characteristics of newly developed compact square‐ring resonators have also been described and applied to the design of bandpass filters. In this paper, the designed square‐ring resonators structures are simulated using an IE3D simulator. The responses of the fabricated bandpass filters using Al2O3 (εr = 9.7, tan δ = 0.000036) and 0.875Mg0.95Zn0.05TiO3‐0.125Ca0.8Sm0.4/3TiO3 (εr = 23.5, tan δ = 0.000021) ceramic substrates are designed at the center frequency of 2.4 GHz. This compact size, low loss bandpass filter should be useful in many wireless communication systems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 218–220, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24847

Fully integrated low-loss band-pass filters for wireless applications

Fully integrated low insertion loss micromachined band-pass filters are designed and fabricated on the silicon substrate (ρ = 10–20 Ω cm, εr = 11.9) for UHF applications. Filters are made of silver, which has the highest conductivity of all metals, to minimize the ohmic loss. A detailed analysis for realizing low insertion loss and high out-of-band rejection filters using elliptic magnitude characteristics is presented, and a comprehensive model to take into account inductive parasitics of the interconnects is developed. Temperature characteristics of the filters are measured and show stable performance. The presented filters are different from the previously reported lumped element filters in that all filters are fully integrated on silicon substrate and occupy a remarkably smaller die area. Two filters are fabricated using the silver micromachining technique with center frequencies at 1.05 and 1.35 GHz. The filters have a constant 3 dB bandwidth of 300 MHz (28.6% and 22.2%) and an insertion loss of 1.4–1.7 dB. The low insertion loss and CMOS compatibility make the presented filters suitable candidates for radio frequency integrated circuits.

구형 공진기와 계단 임피던스 개방 스터브를 사용한 고효율 광대역 대역 통과 필터 특성

본 논문에서는 구형 공진기와 SIOS(Step-Impedance-Open-Stub)를 사용하여 삽입 손실이 적고, 차단 특성이 아주 좁고, 광대역 특성을 갖는 대역 통과 필터를 연구하였다. SIOS는 일반 <TEX>$0.25\;{\lambda}$</TEX> 개방 스터브보다 약 30 %의 길이를 줄일 수 있고, 또한, SIOS의 길이에 따라 임피던스 값을 조정함으로써 필터의 특성 개선에 적용할 수 있다. 본 논문의 객관성을 입증하기 위해서 이중 모드 구형 공진기를 사용한 최적화된 광대역 대역 통과 필터를 구현하였다. 전송 선로 모델을 사용하여 계산한 주파수 특성 결과는 실험값과 아주 잘 일치하였다. 본 논문에서 구현된 필터의 주파수 특성은 필터의 3 dB 대역폭은 51.75 %(3.206 GHz)이고, 삽입 손실은 0.44 dB, 30 dB 차단 특성은 저 주파수 대역에서 221 MHz(<TEX>$4.326{\sim}4.587\;GHz$</TEX>), 고주파수 대역에서 181 MHz(<TEX>$7.739{\sim}7.954\;GHz$</TEX>)이다. 최대 차단 특성은 저주파 대역에서 -61.8 dB, 고주파 대역에서 -76.3 dB이다. This paper presents a compact, low insertion loss, sharp rejection and wide band microstrip band pass filter that is composed rectangular loop resonator and Step-Impedance-Open-Stub(SIOS). The SIOS can be reduce length about 30 % more than general 0.25 <TEX>$\lambda$</TEX> open stub. And the stub can the advantage of tuning impedance magnitude. In order to demonstrate agrement of this paper prove, the optimized wide band pass filters are realized and experimented. A transmission line model used to calculate the frequency response of the new filters shows good agreement with measurements. The filter has 3 dB fractional bandwidth of 51.75 %(3.206 GHz), an insertion loss of better than 0.44 dB from 4.587 GHz to 7.793 GHz, and two rejection of greater than 30 dB within 221 MHz(<TEX>$4.326{\sim}4.587\;GHz$</TEX>) at low frequency band, 181 MHz(<TEX>$7.739{\sim}7.954\;GHz$</TEX>) at high frequency band. Maximum rejection characteristics of the filter are -61.8 dB at low frequency and -76.3 dB at high frequency.

Novel Folded Waveguide Resonator Filter Using Slot Technique

This letter presents a primary investigation into developing a compact and low-loss bandpass filter using novel folded-waveguide resonators with a footprint reduction. A slot coupling between adjacent resonators is introduced, which is characterized using full-wave electromagnetic simulations and verified experimentally. Two two-pole folded-waveguide resonator filters of this type have been designed, fabricated and tested. Simulation and measurement results are presented to validate the design and to show the advantages of this type of filter.

Reduced‐size wideband microstrip bandpass filter with low loss and high selectivity

AbstractA reduced‐size low‐loss high‐selectivity wideband microstrip bandpass filter is proposed using three λg/4 short‐circuited stubs and folded λg/2 connecting lines between them. The filter has 2n − 1 poles within the passband, whereas it consists of only n resonators. The 3‐dB bandwidth of the filter is about 92% at 2.1 GHz. The insertion loss is around 0.8 dB within the passband. The filter is verified by both simulation and measurement. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 147–148, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20751

Low-loss bandpass filter using higher mode strip line for millimetre-wave integrated circuits

A technique to construct a low-loss printed bandpass filter was demonstrated by using a higher mode strip line at 30 GHz. A three-pole, 0.1 dB Chebyshev ripple bandpass filter with a 2% relative bandwidth was designed and fabricated. The insertion loss was found to be 0.7 dB.

Reduced-size dual-mode slotted patch resonator for low-loss and narrowband bandpass filter applications

A compact, low-loss and narrowband dual-mode microstrip filter is proposed using degenerate modes of a microstrip patch resonator loaded with two narrow slots. The resonator structure is fed by inset lines connected directly to the centre of adjacent edges of a microstrip patch with two notches. The dual-mode filter is verified by both simulation and measurement.

Surface-acoustic-wave devices for the 2.5–5 GHz frequency range based on longitudinal leaky waves

The recently discovered “longitudinal leaky” surface acoustic wave on YZ-cut lithium niobate has been used to implement low-loss bandpass filters operating in the 2.5-GHz Bluetooth frequency range. The filter is of the ladder type, employing synchronous resonators as building blocks. Resonator Q-values above 300 have been measured. The filter features a center frequency of 2491 MHz, a minimum insertion loss of 3.5 dB, and a fractional 3-dB bandwidth as wide as 6.2%.