Insertion Loss Of Filter Research Articles

Method for improving ladder bulk acoustic wave filters rejection

This paper address design guidelines for improving the rejection of ladder bulk acoustic wave filters. An overview of the bulk acoustic wave filters technology enables to outcome the principal features of ladder filters. The lack of out-of-band rejection is currently an important weakness of this topology. The design technique presented enables to improve bulk acoustic wave ladder filters rejection by using their input/output bonding wires. Finally, the technique is used for design and fabrication of a bulk acoustic wave ladder filter for application in W-CDMA reception (2.11---2.17 GHz) front-ends. The filter measurement results show a significant improvement on the filter rejection at the transmission band (from ?19 to 34 dB) and on the return loss (from ?10 to ?16 dB) without considerable modification of filter insertion loss and selectivity.

Modified maximally flat parallel‐coupled lines for band‐pass filter applications and miniaturizations

AbstractThe modified configurations of maximally flat parallel‐coupled lines (MF‐PCL) structure are introduced to improve the performance of the conventional MF‐PCL resonator. To obtain a higher rejection (−39 dB), symmetry response, wider band (BW about 32%), and less insertion loss (−0.4 dB) filters at central frequency 5.78 GHz, the modified MF‐PCL resonators by using enhanced coupling techniques are proposed herein. The size reduction of 50% is achieved. Results including surface current distributions and frequency responses are presented and discussed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 902–906, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23243

A Novel Compact Degenerate Dual-Mode Square Patch Filter using Cross H-Shaped Defected Ground Structure

A new degenerate dual-mode cut corner square patch resonator filter with defected ground structure (DGS) is investigated. The patch resonator is analyzed using full wave IE3D simulator. It has been shown that etching cross H-shaped slots in the ground beneath the square patch reduces significantly the patch area. Area saving of more than 80% can be easily achieved using the proposed structure. Compact size with low insertion loss and wide stopband filter is designed, analyzed, and tested. Simulation and experimental results agree well.

A compact bandpass filter with enhanced stopband characteristics by an asymmetric cross-shape defected ground structure

In this paper, we present an effective technique to enhance stopband bandwidth for a bandpass filter by using an asymmetric, cross-shape defected ground structure (CSDGS). A single CSDGS can provide a higher attenuation rate near passband and broader stopband bandwidth. Moreover, with the asymmetric CSDGS, two different resonant frequencies can be excited and controlled independently, resulting in synthesizing a passband. The synthesized bandpass filter can be modeled by parallel LC resonant circuits in connection with T-networks. The bandwidth and insertion loss of this bandpass filter at 4.2 GHz is 28.6% and -1.44 dB, respectively, and 20 dB rejection in the stopband is up to four times the central frequency. All the synthesized bandpass filters have been measured and are in good agreement with simulated results.

A Fully Embedded 60-GHz Novel BPF for LTCC System-in-Package Applications

In this paper, a novel LTCC stripline (SL) 60-GHz band-pass filter (BPF) composed of transitions to coplanar waveguide (CPW) pads for monolithic microwave integrated circuit integration is presented. For low-loss interconnection with active devices, a CPW-to-SL vertical via transition integrating air cavities and a CPW-to-CPW planar transition using internal ground planes are proposed and implemented. The fabricated transition shows an insertion loss of 1.6 dB and a reflection loss below -20 dB at the passband of the filter. The implemented SL BPF using dual-mode patch resonators shows a center frequency of 60.4 GHz, 3.5 % bandwidth, and reflection losses below -15 dB at the passband. Excluding the insertion loss of the transitions, the filter insertion loss reveals 4.0 dB

Terahertz Band-Pass Filter Fabricated by Multilayer Ceramic Technology

We fabricated a terahertz (THz) band-pass filter using multilayer ceramic technology. The filter design is based on an interference multilayer filter composed of three resonant cavities. The filter exhibited insertion loss as low as 1.5 dB at a center frequency of 0.15 THz. The bandwidth of the passband was modified by changing the optical length of the cavity. A demonstrated tuning of the full width at half maximum (FWHM) ranged from 12.5 to 6.9%. No significant change in transmission intensity was observed when the optical length of the cavity was changed. At a frequency of approximately 0.8 THz, filter insertion loss increased from 1.5 to 6 dB. The influence of dielectric losses of the ceramic materials on the filter insertion loss is also discussed.

Influence of monitor passband width on the layer thickness determination during deposition of a dense-wavelength-division-multiplexing filter

The monitor passband width of an optical monitor is an important parameter for the fabrication of a dense-wavelength-division-multiplexing (DWDM) filter. The peak insertion loss and transmittance of one-cavity narrow-bandpass filters (NBPFs) were analyzed by using different passband widths. The simulation monitoring curves of the last layer of the first, second, third, and fourth cavities of a five-cavity DWDM filter with different monitor passband widths were investigated. The last layer of each cavity is very sensitive to the monitor passband width, showing that the monitor passband width of an optical monitor should be less than half the designed passband width. This analysis demonstrates the successful fabrication of a five-cavity DWDM filter.

정렬에 무관한 마이크로옵틱 마하젠더 간섭계형 필터

광섬유형 콜리메이터와 광 진행 경로의 수직 방향으로 삽입된 주기적으로 식각된 줄무늬(stripe) 평판에 의해 진행하는 빔의 일부에 광 경로차를 유도하는 마이크로 옵틱형 마하젠더 간섭형 필터를 제안하고 구현하였다. 제안된 마이크로 옵틱 필터는 주기적으로 식각된 줄무늬(stripe) 구조의 평판을 빔 경로에 삽입하여 측방향 정렬에 무관하게 특정 소멸비 값 이상의 특성을 구현할 수 있으며, 식각된 박막의 두께를 조정함으로써 원하는 대역폭 및 주기의 전달특성을 가지는 필터를 구현할 수 있다. 네거티브 포토레지스터인 SU-8을 기반으로 줄무늬(stripe) 구조의 주기적으로 식각된 평판을 제작하였으며 이를 이용하여 구현된 필터의 소멸비는 측방향 정렬에 무관하게 30 dB이상의 값을 가진다. 제작된 필터의 FSR(Free Spectral Range)은 장파장 대역에서 약 237 nm이고 그리고 삽입손실은 2 dB 미만의 값을 가진다. 통과대역에서의 PDL(Polarisation Dependent Loss)값은 0.15 dB 미만이다. A novel alignment-free micro-optic MZI filter has been demonstrated. The filter is composed of two fiber-pigtailed collimators and a beam-splittingplate with a periodically etched stripe pattern. We fabricated the plate through a standard lithographic formulation process by using a pyrex substrate glass with SU-8 resist coating on its one of the surfaces. The maximum insertion loss of the implemented filter was less than 2 dB over 1000 nm to 1600 nm and the extinction ratio was larger than 33 dB. The measured PDL within the 3-dB pass band of the filter was less than 0.15dB and the maximum extinction ratio variation was less than 2 dB even when the worst alignment error occured.

超伝導アンテナとフィルタのレーザトリミングによる特性改善

Improvements in superconducting device characteristics using laser-etching trimming is examined. A KrF excimer laser (248 nm) was used. As an example, improving the bandwidth of a superconducting patch antenna with gap-coupled resonators and that insertion loss of a 3-pole hairpin-type superconducting filter were studied. We found that laser-etching trimming is quite useful for improving the antenna and filter properties; increasing the bandwidth and reducing return loss with the antenna, and reducing loss with the filter.

Reduction of insertion loss of thin film filters embedded in PLC platforms

We propose and experimentally demonstrate a method of reducing insertion loss of a thin-film-filter-embedded planar-lightwave-circuit platform for a triplexer transceiver module. Significant loss reduction was achieved by adding horn waveguide elements at the interfaces between the thin film filter and the output-port (transmission and reflection) waveguides.

AN HTS FILTER SUBSYSTEM FOR 800MHz MOBILE COMMUNICATION SYSTEM

In this paper, we present a high temperature superconducting (HTS) Filter subsystem, which consists of a 14-pole HTS filter, a low noise amplifier (LNA), a Stirling Cooler and an electronic control system. The HTS filter has a 2.1% fractional bandwidth at 814MHz. It was fabricated on MgO substrate which was double sides coated with YBCO thin films. The insertion loss of the HTS filter is less than 0.2 dB , the gain of the subsystem is 22 dB at 60K . In this subsystem, the out-of-band rejection is better than 70 dB and the steepness of the band-edges is larger than 25 dB/MHz at 60K .

Contributions of the surface resistance of high-temperature superconducting films to the insertion loss of the microwave filters

In this paper it is shown that the influence of the surface resistance of the high_temperature superconductors (HTS) on the insertion losses of the microwave filters with various poles and central frequencies was analyzed using simulat ion software for the electrical circuits. It is shown that HTS thick films or HT S thin films with relatively high surface resistance can be used to construct lo w insertion loss microwave filter with a few poles or with low central frequency . But high_quality epitaxial thin films must be used to construct low loss microwave filter with many poles (more than 8-poles) or with high central frequency (higher than 6GHz).

Fabrication of an X-Band Dual Mode Bandpass Filter Using Low Cost FR4 Substrate

SUMMARY The investigation presents a low cost and low insertionloss X-band dual mode bandpass filter (BPF) based on inexpensive com-mercial FR4 substrate. The proposed filter at a central frequency f 0 of11.3GHz has high filter performance filter with a fractional bandwidth of14%, the insertion loss of −2.7dB, and two transmission zeros. The de-signed procedures are presented in this letter and the fabricated filter veri-fies the proposed designed concept. key words: dual-mode, transmission zero, ring resonator, FR4 1. Introduction Miocrowave communication systems are expanding rapidlyto higher frequency such as C-band or X-band since they canprovide many advantages over conventional wireless links,for example the larger bandwidth and smaller device size.Waveguide components are widely used at these frequenciesand offer very good performance. However, they result inhigh production costs and bulky systems. Conventional pla-nar filter structures suffer from radiation from the resonatorsinto the substrate and from high ohmic loss, and there-fore give high insertion loss and poor filter rejection. Re-cently, the micromachined techniques have been providedand shown to enhance filter performance by removing thedielectric material up to a thin membrane that suspends theplanar filters, therefore reducing of the radiation, ohmic,and dielectric losses of resonators [1],[2]. However, thereis still a challenge in cost down of the commercial RF mi-cromachined device since the devices are fabricated in thesemiconductor-like process.In this letter, we have succeeded to fabricate an lowcost and low loss X band dual mode BPF by using inex-pensive commercial FR4 GD (Glass-Epoxy Double Sided)substrates with thickness of 0.4mm and original relative di-electric constant e

Optical demultiplexer filtering to increase the uncompensated reach of 10-Gbit/s directly modulated lasers

Significant uncompensated reach extension of highly chirped 10-Gbit∕s directly modulated lasers is demonstrated by use of optical filtering provided by optical demultiplexers at the link end. Narrowband filtering narrows the optical spectrum of the chirped signal to minimize dispersion effects when the filter's center wavelength is appropriately adjusted relative to the laser wavelength. We show that an equivalent reach improvement is obtained with a dense wavelength division multiplexing (DWDM) demultiplexer as the filtering agent with optimal filter-laser alignment. Experimental uncompensated reach lengths of greater than 100 km of Corning LEAF® fiber are demonstrated, without the need for forward error correction. This represents a reach improvement of up to 50% in comparison with nominally unfiltered signal transmission. We also examine the correlation of performance with the filter insertion loss derivative.

Effects of Si 3N 4 and DLC passivation layers on characteristics of SAW filters

Silicon nitride (Si 3N 4) and diamond-like carbon (DLC) passivation layers were deposited on Surface Acoustic Wave (SAW) filters with Al inter-digital electrodes formed on LiTaO 3 substrates. The adhesion of the DLC film to LiTaO 3 substrate has been enhanced by introducing SiO 2 interlayer. Si 3N 4 passivation layer is found to be capable of minimizing the variations of both insertion loss and bandwidth of the SAW filters during power durability test (PDT), while DLC layers show little effect on these variations.

An m‐derived ladder high‐pass SAW filter

AbstractSince excellent characteristics can be realized in the gigahertz range with a small size, SAW filters have been used widely as RF (radio frequency) filters for mobile communications terminals. In particular, since the insertion loss of the RF filter impacts the receiving sensitivity and transmitting power efficiency of the terminals, the demand for lower loss is substantial. In this paper, a one‐port SAW resonator is used as the series element and a series circuit consisting of a capacitor and an inductor is used as the shunt element in an m‐derived ladder filter. Its configuration, design procedure, and design and test results are presented. In spite of a simple circuit configuration, this filter can realize a low loss characteristic. The fabricated filter for 900 MHz exhibited excellent properties with an insertion loss of less than 1 dB and an out‐of‐band attenuation of more than 33 dB. The effectiveness of this filter is therefore demonstrated. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 27–36, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20091

Low Loss Intermediate-Frequency Resonator Filter Using Shear Horizontal Type Leaky Surface Acoustic Wave on α-Phase Heavy Metal Film/Quartz

By applying a new shear horizontal (SH)-type leaky surface acoustic wave (LSAW) excited by interdigital transducers (IDTs) and reflectors made of Ta or W on an ST-cut 90°X-propagation (direction perpendicular to X-axis) quartz substrate, we succeeded in fabricating very small resonator filters (1/5–1/4 of conventional device sizes). However, the Ta and W films used in our filters were β-Ta and β-W, which have resistances higher than that of an Al film. α-Ta and α-W films with very low resistivities have been successfully deposited in place of β-Ta and β-W films. The insertion loss of resonator filters consisting Ta- or W-electrode/ST-90°X quartz has been improved by 1.5–8 dB using the α-Ta or the α-W film electrode.

The dispersion properties of surface acoustic wave devices on AlN/LiNbO 3 film/substrate structure

Highly c-axis oriented aluminum nitride (AlN) films were deposited on z-cut LiNbO 3 substrates by reactive rf magnetron sputtering. The crystalline properties investigated by X-ray diffraction (XRD) revealed that AlN film with (0 0 2) preferred orientation was improved by an increase of the deposition time within the experimental range. However, the surface morphology of AlN film measured by scanning probe microscopy (SPM) showed that the roughness was getting worse with increase of deposition time. Surface acoustic wave (SAW) properties, measured by a network analyzer in the structure consisting of highly c-axis AlN films on z-cut LiNbO 3 substrates, were investigated. The phase velocity (V P) was significantly increased by the increase of h/ λ, where h is the thickness of AlN film and λ is the wavelength. However, the insertion loss (IL) of SAW filters was also increased by the increase of h/ λ. Experimental results on the temperature characteristics of SAW devices are also presented.

Micromechanical Mixer-Filters (“Mixlers”)

A device comprised of interlinked micromechanical resonators with capacitive mixer transducers has been demonstrated to perform both frequency translation (i.e., mixing) and highly selective low-loss filtering of applied electrical input signals. In particular, successful downconversion of a 200-MHz radio frequency (RF) signal down to a 37-MHz intermediate frequency (IF) and subsequent high-Q bandpass filtering at the IF are demonstrated using this single, passive, micromechanical device, all with less than 13 dB of combined mixing conversion and filter insertion loss. The mixer-filter (or "mixler") RF-to-IF voltage transfer function is shown to depend upon a ratio of local oscillator amplitude and applied bias voltages.

Micromachined 300 GHz high Q resonant slot frequency selective surface filter

The design of a low loss quasi-optical beam splitter which is required to provide efficient diplexing of the bands 316.5–325.5 GHz and 349.5–358.5 GHz is presented. To minimise the filter insertion loss, the chosen architecture is a three-layer freestanding array of dipole slot elements. Floquet modal analysis and finite element method computer models are used to establish the geometry of the periodic structure and to predict its spectral response. Two different micromachining approaches have been employed to fabricate close packed arrays of 460 μm long elements in the screens that form the basic building block of the 30 mm diameter multilayer frequency selective surface. Comparisons between simulated and measured transmission coefficients for the individual dichroic surfaces are used to determine the accuracy of the computer models and to confirm the suitability of the fabrication methods.