Tunable active filters having multilayer structure using LTCC

Kageyama, Kensuke; Saito, Keizo; Murase, Hiromu; Utaki, H.; Yamamoto, Takashi

doi:10.1109/mwsym.2001.967174

Cited by 13 publications

(11 citation statements)

References 2 publications

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“…the i th element of the ladder circuit prototype C capacitance C i , C s i th self-capacitance C i,i+1 , C m i th mutual capacitance θ min minimum midband electrical length C t total capacitance S/H gap ratio in a coupled line W/H shape ratio in a coupled line x distance from the clamping point t thickness of a single piezoelectric layer L × W × T cantilever dimensions h distance between the laser source and the PSD detector d reference distance that result from the calibration D cantilever deflection τ F tunability factor f 0 center frequency of the frequency agile component at no bias f Vmax center frequency of the component at the maximum applied bias S 21 transmission coefficient of a filter S 11 reflection coefficient of a filter Q loaded loaded quality factor S 21 (f 0 ) transmission coefficient of the filter at the mid-band frequency f 0 Q unloaded unloaded quality factor K nm mutual-coupling between lines n & m L i inductance of the transmission line (i) R a filter ohms and dielectric losses R s cantilever ohmic losses …”

Section: List Of Abbreviationsmentioning

confidence: 99%

“…Particularly noticeable are varactor diodes [6], paraelectric capacitors [7], and micro electromechanical system (MEMS) capacitors [8]. A specific characteristics of a varactor diode is its depletion region capacitance which can be varied by the applied bias voltage [9].…”

Section: State Of the Artmentioning

confidence: 99%

“…Therefore, circuits requiring high Q values, such as wide tunable bandpass filter, do not rely on this sort of varactor. Kageyama et al [11] have developed a tunable active filters with multilayer LTCC structure. The tunability was attained with the help of varactor diodes.…”

Section: State Of the Artmentioning

confidence: 99%

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Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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This work treats design and fabrication issues associated with innovative tunable front-end components which combine two different ceramic technologies, namely multilayer ceramic circuit boards (low temperature cofired ceramics or LTCC) and piezoelectric actuator technology within a single device. The need for such components is particularly arising due to the increasing number of wireless services and associated frequency bands in the range between 0.5 and 2.5 GHz. This has led in the past to the concept of software-defined radio (SDR) which would provide a cost-efficient solution by treating signals digitally and software-controlled up to the highest possible frequencies and as close as possible towards the transmit antenna, while the final analogue section at the antenna comprises only few high-performing and frequencyagile, tunable components. However, as a consequence of demanding component specifications, SDR has not yet found noticeable application in consumer markets despite ongoing search for suitable device concepts and fabrication technologies.Similar to the known micro-electromechanical (MEMS) approaches for tuning and switching, this work presents a modified parallel plate capacitor with high-permittivity dielectric and piezoelectrically movable top electrode as a tuning element. Like in MEMS solutions, there is no tunable dielectric material required for tuning as for example paraelectric material, which would introduce additional losses. The proposed device therefore has the potential for a high quality factor. Contrasting MEMS, piezoelectric actuators exhibit proven reliability and lifetime. Also sticking of contact surfaces can be overcome by the actuator force. The size of the actuator in the order of several millimeters is not impedimental in the present context, since it compares well to the size of planar integrated filters in the frequency range mentioned.The vertical movement of the electrode opens an air gap above the dielectric film which allows for substantial lowering of the effective dielectric constant and capacitance. When applied as a shunt capacitor in a coupled microstrip lines LTCC bandpass filter, the center frequency of the filter is tuned from 1.1 GHz to 2.6 GHz (tunability of 135%) with 200 V control voltage and low insertion loss of value 4 dB (at zero-bias) to 2 dB (at the maximum bias). For a more compact size, one electrode of the piezoelectric element is simultaneously used as the center microstrip line of a filter employing three coupled lines. Its equivalent circuit has been used to explore the change of the capacitor parameters across the entire tuning range. The capacitor varied from 7 pF to 1.35 pF with a quality factor between 60 and 160. The quality factor could be improved by a factor of 7 when the metallization of the piezoelectric actuator, changes from 80 nm to 500 nm.This thesis discusses also the effects of tuning mechanism on the overall quality factor, return loss, insertion loss, and the relative bandwidth at the mid of the band as a function of ...

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Section: List Of Abbreviationsmentioning

confidence: 99%

Section: State Of the Artmentioning

confidence: 99%

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Wide piezoelectric tuning of ltcc bandpass filters

Alahmad

Mäenner

Matz

et al. 2005

IEEE MTT-S International Microwave Symposium Digest, 2005.

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“…For Re{ r } ϭ 4.2, 5.9, 7.8, and 8.4, the materials are the low-temperature co-fired ceramics (LTCCs). It is known that LTCCs show excellent highfrequency performance, including low insertion loss and good loss tangent characteristics [13][14][15][16]. In Figure 4, as r decreases, the V-shaped microstrip line becomes less dispersive.…”

Section: Change In Rmentioning

confidence: 99%

Dispersion characteristics of V‐shaped microstrip lines

Guo

Dong

Wang

et al. 2003

Micro & Optical Tech Letters

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“…Because LTCCs have excellent high-frequency performances, they have been widely used as substrates or superstrates in high-density interconnects and packaging systems [10,11]. This paper is organized as follows: in section 2, the geometry of a LTCC CPW is shown, and some formulas to determine the dielectric loss, radiation leakage loss and ohmic loss are introduced.…”

Section: Introductionmentioning

confidence: 99%

Lossy effects on the transient propagation in LTCC coplanar waveguides (CPWs)

Wang

Guo

Dong

et al. 2003

Micro & Optical Tech Letters

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The effects of dielectric, radiative leakage and ohmic losses in CPWs on the propagation of Gaussian and sinusoidally modulated Gaussian pulses are investigated. These CPWs are assumed to be fabricated on a single‐layer low‐temperature co‐fired ceramic (LTCC) substrate. It is shown that, based on the improved empirical formula for accurate prediction of the ohmic attenuation constant presented by Liao et al., the lossy effects in LTCC CPWs are dominated by the ohmic loss of the center and ground conductive planes in the frequency range up to 40 GHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 94–97, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11137

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Tunable active filters having multilayer structure using LTCC

Cited by 13 publications

References 2 publications

Wide piezoelectric tuning of ltcc bandpass filters

Wide piezoelectric tuning of ltcc bandpass filters

Dispersion characteristics of V‐shaped microstrip lines

Lossy effects on the transient propagation in LTCC coplanar waveguides (CPWs)

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