Multilayer Low-temperature Co-fired Ceramic Technology Research Articles

Ceramic multilayer technology as a platform for miniaturized sensor arrays for water analysis

Abstract. Ion-selective electrodes (ISEs) have been proven particularly useful in water analysis. They are usually used as single-rod measuring chains in different designs, which are manufactured using precision mechanical manufacturing and assembling technologies. The paper describes a microsystem technology approach for the fabrication of miniaturized electrochemical sensors. The ceramic HTCC (high-temperature co-fired ceramic) and LTCC (low-temperature co-fired ceramic) multilayer technology enables suitable processes for the manufacturing of robust and miniaturized sensor arrays with a high functional density. Design, manufacture, and electrochemical performance of the novel ceramic multilayer-based sensor array are presented in the paper using various examples. An adapted material and process development was carried out for the sensitive functional films. Special thick-film pastes for the detection of the pH value as well as NH4+, K+, Ca2+, and Cu2+ ion concentrations in aqueous solutions were developed. Ion-sensitive thick-film membranes were deposited on a ceramic multilayer sensor platform by means of screen-printing. All ISEs, integrated in the sensor array, showed suitable electrochemical performances including a very quick response (several seconds) combined with a high sensitivity (exhibiting Nernstian behaviour) in the tested measuring range. The obtained sensitivities were around 57 mVper decade: for the pH sensor, 30 mVper decade for calcium, 53 mVper decade for potassium, and 57 mVper decade for ammonium. Depending on the application, different sensitive electrodes on the ceramic sensor array can be combined as required.

Miniaturized tunable bandstop filter using multilayer technology

AbstractA new type of miniaturized tunable bandstop filter (BSF) based on multilayer technology is presented in this letter. One of the transmission zero could be individually tuned by replacing an outer replaceable element, which can be considered as part of the inner resonant cell of the bandstop filter. Thus, a tradeoff between the stopband rejection depth and bandwidth can be conveniently realized according to different applications. A bandstop filter works from 3.1 to 4.2 GHz has been designed and fabricated in a low temperature cofired ceramic (LTCC) substrate to verify the proposed concept. By virtue of the LTCC multilayer technology, the filter occupies a very compact volume of 2.0 mm × 1.2 mm × 0.8 mm.

A compact LTCC semi‐lumped highpass filter with vialess structure

AbstractA new type of semi‐lumped highpass filter (HPF) based on multilayer technology is presented in this letter. Capacitive coupled stripline stubs are utilized as semi‐lumped resonators in the structure without using any means. Hence, undesired parasitic effect in the multilayer interconnections is minimized while high quality factor and stopband rejection are realized simultaneously. In this research, a HPF works from 5.15 to 5.95 GHz has been designed and fabricated on a low temperature cofired ceramic (LTCC) substrate. The proposed topology has been validated through a series of tests. By virtue of the LTCC multilayer technology, the proposed HPF is compact, occupying only a volume of 2.5 mm × 2.0 mm × 1.0 mm.

A Low-profile Ultra-wideband LTCC Based Microstrip Antenna for Millimeter-wave Applications under 100 GHz

In this paper, a low profile ultra-wideband microstrip antenna is proposed for millimeter wave applications below 100 GHz to meet the demands of high data rates in the future wireless communication systems. The proposed antenna consists of a non-uniform hexagon shape radiating element on the top of 13th layer of ceramic. The proposed antenna geometry is designed using Low Temperature Co-fired Ceramic (LTCC) technology for 3D multilayer vertical integration. HFSS and CST Studio are used for design and simulation of this ultra-wideband antenna. This antenna covers a bandwidth of 33.5 GHz that ranges from 62.5 GHz to more than 96 GHz with a peak gain of 5.7 dBi, stable radiation pattern across the bandwidth, and compact size of 3.16  3.2 mm 2. The limitation of the narrow band in microstrip antenna is successfully dispensed by increasing the matching impedance bandwidth to more than 40 %. The proposed microstrip antenna is very useful for modern wireless communication systems because of its capability of covering a very wide bandwidth with favorable impedance matching and a stable radiation pattern at the considered frequency range. This antenna has another advantage in terms of the ability to be directly integrated with other RF chips using LTCC multilayer technology.

A Compact LTCC Decoupling-Network Based on Coupled-Resonator for Antenna Interference Suppression of Adjacent Frequency Bands

A low-temperature co-fired ceramic (LTCC) coupled resonator decoupling network (CRDN) with asymmetric input/output (I/O) couplings for suppressing interference between two adjacent frequency bands is proposed in this paper. Based on LTCC multilayer technology, a second-order CRDN module is realized by strongly coupled semi-lumped LC resonators in a very small volume of 3.2 mm $\times2.5$ mm $\times1.2$ mm. A wide range of mutual admittance and different self-admittances of the CRDN can be realized by adjusting the asymmetric I/O couplings. Thus, a satisfactory decoupling performance covering two contiguous bands, as well as good matching in each band, can be realized without additional matching networks. To prove the concept, two planar inverted-F antennas working in TD-LTE and Wi-Fi frequency bands, along with the corresponding decoupling network, are designed, fabricated, and tested. The measured results have demonstrated that more than 15-dB isolation improvement can be achieved within the two operating bands, showing the feasibility of this ”one-fit-all” integrated solution. More importantly, the design methodology and circuit topology presented in this paper are general and can be applied to practical multi-input multi-output system applications.

Compact 60 GHz low‐temperature cofired ceramic filter with quasi‐elliptic bandpass response

This study presents a 60 GHz quasi-elliptic bandpass filter with a compact and planar structure. The proposed filter was constructed by stacking substrate integrated waveguide (SIW) cavities on the central transverse plane of a shielding SIW cavity. Jerusalem cross (JC) apertures and circular apertures were etched on the metal layers of the stacked SIW cavities to enable dual-mode operation and energy coupling. In the dual-mode cavities, the TM110 cavity mode and JC aperture mode can be excited simultaneously. Cross-mutual couplings exist among the resonant modes, resulting in two finite transmission zeros with each at either side of the passband. Multilayer low-temperature cofired ceramic technology was adopted to manufacture the experimental filter. The measured centre frequency was 60 GHz at a fractional bandwidth of 4.5% with two finite transmission zeros located at 53.7 and 65 GHz, thereby achieving high-frequency selectivity.

Wideband 60 GHz circularly polarised stacked patch antenna array in low‐temperature co‐fired ceramic technology

A wideband circularly polarised (CP) cross-aperture-coupled stacked feed antenna array with the top-metal strip via fence based on multilayer low-temperature co-fired ceramic technology is designed and measured for 60 GHz wireless communication applications. The influence of the large substrate and ground size on the radiation patterns of the proposed CP antenna array is investigated. Considering the 10 dB impedance bandwidth, 3 dB axial ratio bandwidth and 3 dB gain bandwidth, the measured results reveal that a wide operating bandwidth more than 17% at the centre frequency of 61.75 GHz from 56.5 to 67 GHz of the presented CP antenna array is achieved.

A Laminated Waveguide Magic-T With Bandpass Filter Response in Multilayer LTCC

A laminated waveguide magic-T with imbedded Chebyshev filter response is developed in a multilayer low-temperature co-fired ceramic technology by vertically stacked rectangular cavity resonators with highly symmetric coupling structures. The cavities provide even- and odd-symmetric field distributions by simultaneously resonating TE102 and TE201 modes at the center frequency of the magic-T. Thus, the in-phase and out-of-phase responses of the magic-T function are accomplished according to the induced mode. Meanwhile, the filter frequency response is realized by the cascaded cavities with proper coupling strengths according to the filter specification. With the degenerate, but orthogonal cavity modes, a fewer number of cavities are required and the circuit size is further reduced. A third-order bandpass magic-T is designed and fabricated to operate at 24 GHz with 6% fractional bandwidth. The highly symmetric structure of the implemented magic-T provides a low in-band magnitude imbalance ( ±0.25 dB) and phase imbalance (0°-6°). The sum and difference ports also provide an isolation greater than 30 dB in the operation frequency range. Measurement and simulated results are in good agreement, both validating the design concept.

Dual-band UWB filter with LTCC technology

A dual-band UWB bandpass filter with compact size is reported using low-temperature cofired ceramic (LTCC) technology. By coupling a multimode resonator and two short-circuit lines to common input/output feedlines, not only a dual-band UWB filter is obtained, but also four transmission zeros are generated to enhance the out-of-band rejection. A good agreement is achieved between simulation and measurement. Based on the multilayer LTCC technology, the filter occupies only a size of 6.0×6.0×1.92 mm.

An embedded multilayer LTCC band‐pass filter using U‐type stepped impedance resonator

AbstractThis article proposes a compact multilayer band‐pass filter based on low‐temperature co‐fired ceramic (LTCC) technology.The filter is constructed using U‐type stepped impedance resonators (SIR) with microstrip input and output ports. To validate the proposed filter, a three‐order X‐band Chebyshev band‐pass filter is developed and verified by full‐wave simulation. The proposed filter is fabricated using multilayer LTCC technology and measured using vector network analyzer (VNA). Covering area of the fabricated band‐pass filter is only 15.3 × 6.7 mm2 (including via fences). The filter exhibits an insertion loss of lower than 1.8 dB with a 3.2% bandwidth at a center frequency of 9.5 GHz, and the return loss is better than 10 dB in the pass‐band. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1877–1880, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25352

A compact and low‐loss LTCC diplexer with high‐band selectivity and high isolation for dual‐band applications

AbstractThis article presents a compact and low‐loss diplexer for dual‐band applications using a LTCC (low temperature co‐fired ceramic) multilayer technology. This diplexer is composed of the high‐pass filter (HPF) and low‐pass filter (LPF) in order to separate GSM (global system for mobile) and CDMA (code division multiple access) band. For enhancing band selectivity of the diplexer, a shunt capacitor and inductor are designed in the HPF and LPF, respectively. In addition, a transmission zero is designed at the stopband of the LPF using a shunt inductor for improving isolation characteristics. The diplexer is realized in a 6‐layer LTCC substrate with a relative dielectric constant of 7. The size of the fabricated diplexer including CPW pads is 3.45 × 4.0 × 0.7 mm3. A measured insertion loss (IL) and return loss (RL) of the GSM band are less than −0.54 dB and −10.50 dB, respectively. In the case of CDMA band, the IL of −1.13 dB and RL of below −6.16 dB are archived. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1134–1137, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25137

Microchip electrophoresis in low‐temperature co‐fired ceramics technology with contactless conductivity measurement

In this paper a novel micromachined contactless conductivity CE device produced in low temperature co-fired ceramics (LTCC) is introduced. The application of LTCC multilayer technology provides a promising method for the contactless detection of conductive compounds because of its increased dielectric constant compared with glass or plastics. The capacitive coupling of the excitation signal into the microchannel across the LTCC substrate is improved, resulting in better detection sensitivity. Two silver electrodes located externally at opposite sides at the end of the separation channel act as detector. Impedance variations in the channel are measured without galvanic contact between electrodes and fluid. Inorganic ions are separated in less than 1 min with this novel ceramic device. The limit of detection is 10 microM for potassium.

X-band T/R-module front-end based on GaN MMICs

Amplifiers for the next generation of T/R modules in future active array antennas are realized as monolithically integrated circuits (MMIC) on the basis of novel AlGaN/GaN (is a chemical material description) high electron mobility transistor (HEMT) structures. Both low-noise and power amplifiers are designed for X-band frequencies. The MMICs are designed, simulated, and fabricated using a novel via-hole microstrip technology. Output power levels of 6.8 W (38 dBm) for the driver amplifier (DA) and 20 W (43 dBm) for the high-power amplifier (HPA) are measured. The measured noise figure of the low-noise amplifier (LNA) is in the range of 1.5 dB. A T/R-module front-end with mounted GaN MMICs is designed based on a multi-layer low-temperature cofired ceramic technology (LTCC).

A miniature X‐band‐embedded multilayer band‐pass filter using LTCC technology

AbstractThis article proposes a miniature embedded multilayer interdigital bandpass filter (BPF) based on low temperature co‐fired ceramic (LTCC) technology, which is used to suppress fundamental and harmonic components of local‐oscillator signal in a LTCC transceiver module. A practical design methodology corresponding to LTCC multilayer configuration is described. A five‐order Chebyshev interdigital BPF is developed and verified by full‐wave simulation. The proposed filter is fabricated using multilayer LTCC technology and measured using vector network analyzer. Good agreement between simulated and measured response is observed. Covering area of the fabricated BPF is only 8.1 × 7.4 mm2 (including via fences). © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1722–1725, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24432

Three‐pole cross‐coupled substrate‐integrated waveguide bandpass filters based on PCB process and multilayer LTCC technology

AbstractThis letter presents the design, implementation and experiment of planar and multilayer three‐pole cross‐coupled bandpass filters realized by substrate‐integrated waveguide (SIW). The two three‐pole filters centered at 10 GHz with one transmission zero are simulated by using full‐wave electromagnetic (EM) simulator. Then they are fabricated with printed circuit board (PCB) process and with multilayer low‐temperature co‐fired ceramic (LTCC) technology, respectively. By the comparison between the two filters, it is easily seen that the multilayer SIW filter based on LTCC technology occupies a very small area while obtaining good performance. The measured results coincide with the simulated results very well and show the superiority of multilayer LTCC technology. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 71–73, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23972

Dual‐mode filters based on substrate integrated waveguide by multilayer LTCC technology

AbstractThis letter presents the design and experiment of a single‐cavity dual‐mode bandpass filter and a double‐cavity dual‐mode bandpass filter realized by substrate integrated waveguide (SIW) structure. Both the filters are designed and simulated by network theory and high frequency structure simulator (HFSS), and fabricated using multilayer low‐temperature co‐fired ceramic (LTCC) technology. The measured results show good agreement with the simulated results and validate the structures of the proposed dual‐mode filters. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2788–2790, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23829

Design of Vertically Stacked Waveguide Filters in LTCC

This paper proposes four-pole quasi-elliptic function bandpass waveguide filters using multilayer low-temperature co-fired ceramic technology. The vertical metal walls of the waveguide resonators are realized by closely spaced metallic vias. Adjacent cavities are coupled by a narrow slot at the edge of the common broad wall or an inductive window on the sidewall. Two types of vertical coupling structures are utilized to achieve the cross coupling between nonadjacent resonators at different layers. With multilayer capability, there is more flexibility to arrange the cavities of coupled resonator filters in 3-D space. It is demonstrated by both the simulation and experiment that the proposed filter structures occupy a compact circuit area and have good selectivity. The filter with electric field cross coupling occupies a half area of a planar four-pole waveguide filter, while the filter with stacked vias cross coupling has 65% size reduction in comparison with a planar waveguide filter.

LTCC 공법을 사용한 Cellular/SDMB 안테나-다이플렉서 모듈

본 논문은 Cellular 대역과 SDMB(Satellite Digital Multimedia Broadcasting) 대역에서 동작하는 무선 통신 시스템을 위한 송수신 전치단의 소형 안테나-다이플렉서 모듈을 설계하고 구현하는 방법을 제안한다. 제안된 모듈은 이중 공진 안테나와 다이플렉서로 구성되고, 저 손실과 소형화를 동시에 달성하기 위해 다층의 LTCC(Low Temperature Co-fired Ceramic) 기술을 이용하여 제작되었다. 이중 공진 안테나는 소형화를 위해 미앤더 라인을 사용하였고, 임피던스 매칭을 쉽게 이루기 위해 IFA(Inverted-F Antenna) 구조를 응용하여 설계하였으며, 간단한 구조를 지니면서 사양을 만족하는 이득과 대역폭을 갖는다. 다이플렉서는 저역 통과 필터 및 고역 통과 필터를 결합하여 설계되었고, 이들 사이의 상호 간섭을 줄임으로써 높은 격리도를 얻을 수 있었다. 제작된 모듈의 크기는 <TEX>$27.5{\times}12.0{\times}2.2mm$</TEX>이고, <TEX>$813{\sim}902MHz,\;2,586{\sim}2,655MHz$</TEX>의 동작 주파수 대역과 -1.96 dBi(cellular band), -5.43 dBi(SDMB band)의 이득이 측정되었다. 주파수 응답 특성과 방사 특성이 분석되었다. This paper presents an integrated packaging antenna-diplexer module for wireless communication systems in the Cellular and SDMB band. The design and the realization of the proposed one are experimentally analyzed and discussed. It consists of a dual-resonance antenna and a diplexer with a multi-layer LTCC(<TEX>${\varepsilon}_r=7.8,\;tan\;{\delta}=0.0043$</TEX>) technology with integration capability and low loss. The dual-resonance antenna of the proposed module has the meander line structure for size reduction and has the shorting structure of an inverted F antenna to achieve good impedance matching. The diplexer of the proposed module was designed with the combination of low pass filter(LPF) and high pass filter(HPF). Decreasing the mutual interference between them provides a high isolation characteristic. The proposed antenna-diplexer module with dimensions of <TEX>$27.5{\times}12.0{\times}2.2mm$</TEX> operates within a range from 813 MHz to 902 MHz for the cellular band and from 2,586 MHz to 2,655 MHz for the SDMB band. And the measured gain of the fabricated module is -1.96 dBi for Cellular band and -5.43 dBi for SDMB band. The parameters for the antenna-diplexer module are investigated and the several performances are discussed.

A V-band front-end with 3-D integrated cavity filters/duplexers and antenna in LTCC technologies

This paper presents a compact system-on-package-based front-end solution for 60-GHz-band wireless communication/sensor applications that consists of fully integrated three-dimensional (3-D) cavity filters/duplexers and antenna. The presented concept is applied to the design, fabrication, and testing of V-band (receiver (Rx): 59-61.5 GHz, transmitter (Tx): 61.5-64 GHz) transceiver front-end module using multilayer low-temperature co-fired ceramic technology. Vertically stacked 3-D low-loss cavity bandpass filters are developed for Rx and Tx channels to realize a fully integrated compact duplexer. Each filter exhibits excellent performance (Rx: IL<2.37 dB, 3-dB bandwidth (BW) /spl sim/3.5%, Tx: IL<2.39 dB, 3-dB BW /spl sim/3.33%). The fabrication tolerances contributing to the resonant frequency experimental downshift were investigated and taken into account in the simulations of the rest devices. The developed cavity filters are utilized to realize the compact duplexers by using microstrip T-junctions. This integrated duplexer shows Rx/Tx BW of 4.20% and 2.66% and insertion loss of 2.22 and 2.48 dB, respectively. The different experimental results of the duplexer compared to the individual filters above are attributed to the fabrication tolerance, especially on microstrip T-junctions. The measured channel-to-channel isolation is better than 35.2 dB across the Rx band (56-58.4 GHz) and better than 38.4 dB across the Tx band (59.3-60.9 GHz). The reported fully integrated Rx and Tx filters and the dual-polarized cross-shaped patch antenna functions demonstrate a novel 3-D deployment of embedded components equipped with an air cavity on the top. The excellent overall performance of the full integrated module is verified through the 10-dB BW of 2.4 GHz (/spl sim/4.18%) at 57.45 and 2.3 GHz (/spl sim/3.84%) at 59.85 GHz and the measured isolation better than 49 dB across the Rx band and better than 51.9 dB across the Tx band.

Dual-bandpass filters with serial configuration using LTCC technology

A dual-bandpass filter that utilizes a serial configuration of the inductive coupled-line (ICL) filter and the capacitive coupled-line (CCL) filter is investigated in this study. Numerical analysis is presented for the difference between the ICL and CCL filters. The dual-bandpass filter has a similar behavior to the individual single-band filter around the corresponding passband. An extra transmission zero can be generated between the two passbands of the dual-bandpass filter in that the ICL and CCL filters exhibit an out-of-phase response. Four architectures of dual-bandpass filters are proposed for the 2.4/5-GHz systems. Two of them are demonstrated by the low-temperature co-fired ceramic multilayer technology. Measurements results agree quite well with the simulation ones.