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- 实验方案
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A lithium aluminium borate composite microwave dielectric ceramic with low permittivity, near-zero shrinkage, and low sintering temperature
摘要： A low temperature co-fired dielectric material with low shrinkage during the sintering process can enhance the circuit design of electronic devices. Lithium aluminium borate composite ceramic with a composition of Li2O:Al2O3:B2O3=1:1:2 (abbreviated: LAB) was prepared by a traditional solid-state reaction method. These ceramics have a low sintering temperature (675–750 °C), low permittivity, and near-zero shrinkage. When the sintering temperature was 725 °C, the LAB ceramics exhibited a small shrinkage of ~2.4% and the best microwave dielectric properties with εr = 3.9, Q × f = 35?500 GHz, and τ? = -64 ppm/°C. The LAB ceramics sintered at 700 °C have near-zero shrinkage of ~ 0.4% and good microwave dielectric properties. The ceramics transformed from (Li2B4O7 and Al2O3) to (Li2Al2B4O10 and Li4Al4B6O17) phases with increasing the sintering temperature, which may be the reason why they show marginal shrinkage. In addition, the ceramics could be co-fired with Ag, indicating that this material is a good candidate for low-temperature co-fired ceramic devices.
关键词： Low temperature co-fired ceramic,Lithium aluminium borate composite,Near-zero shrinkage
更新于2025-09-23 15:23:52
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Millimetre-wave low-temperature co-fired ceramic bandpass filter with independently controllable dual passbands
摘要： This study presents a detailed investigation on the frequency properties of the stub-loaded stepped-impedance resonator (SIR). For the first time, the frequency controllability of the third and fifth harmonic resonant frequencies (f3 and f5) of the SIR under different ratios of impedance and electric length is subjected to a complete theoretical analysis. It can be found that there is a length ratio which makes f3 and the voltage-null point at f3 never be affected by the change of the impedance ratio. Furthermore, the stub loaded at this voltage-null point also has no effect on f3. These features are successfully applicable to realise independent frequency control for dual-band bandpass filters (BPFs). In this situation, a new coupling path through the loaded stub can be constructed only for f5, and the coupling coefficients for the two bands can be individually varied. Accordingly, both the operational frequencies and bandwidths of the two bands can be separately adjusted. For demonstration, an independently controllable dual-band BPF operating at 27.5/33?GHz is designed and fabricated for millimetre-wave wireless applications. Good accordance is achieved between the simulated and measured results.
关键词： low-temperature co-fired ceramic,independently controllable,bandpass filter,dual passbands,millimetre-wave
更新于2025-09-23 15:21:21
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Low-temperature co fired ceramic materials with three different dielectric constants
摘要： A new type of low-temperature co-fired ceramic (LTCC) material with a medium dielectric constant was developed in this study (MK, εr = 20.9). MK can be co-fired with a high-dielectric-constant material (HK, εr = 44.5) and a low-dielectric-constant material (LK, εr = 8.1) previously reported. Glass and ceramic materials similar to HK and LK were used. The compositions of glass and ceramic materials for MK were designed to set the adequate dielectric constant and low-temperature coefficient of the dielectric constant (τεr). The coefficient of thermal expansion (CTE) was matched with those of both the previous materials. MK was confirmed to match well electrically with both the previous materials, had no mechanical defects, and showed minimal inter-diffusion. With the addition of MK, the three types of LTCC material system contribute to the enhancement of the performance and the downsizing of electronic components for high-frequency communication.
关键词： electronic components,high-frequency communication,dielectric constant,co-firing,low-temperature co-fired ceramic
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Atlanta, GA, USA (2019.7.7-2019.7.12)] 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting - Grounded Coplanar Waveguide-Fed Millimeter Wave Volumetric Pyramidal Horn on LTCC
摘要： There is a strong interest to implement antenna-in-package (AiP) systems for a variety of applications such as imaging, beamforming, integrated transceivers, and radars. Substrate integrated horn antennas are valuable AiP candidates due to their small form factor, ease of integration, and high gain. Alternatively, a volumetric packaging approach can significantly reduce the antenna’s form factor and enhance the gain. For the first time, in this paper, we present a 94 GHz low temperature cofired ceramic (LTCC) integrated volumetric pyramidal horn antenna. Using a vertical LTCC approach, a GCPW-fed single horn antenna was designed. Results show that the antenna operates from 91.6 GHz to 95.6 GHz for S11 <10 dB, with a realized gain of 8.7 dBi.
关键词： Antenna in Package,Low Temperature Co-fired Ceramic (LTCC),Volumetric Horn Antenna,94 GHz
更新于2025-09-11 14:15:04
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Liquid Crystal Based SPDT with Adjustable Power Splitting Ratio in LTCC Technology
摘要： This paper presents design and characterisation of a new liquid crystal (LC) based single-pole double-throw (SPDT) with continuously adjustable power splitting ratio in low temperature co-fired ceramic (LTCC) technology. It is designed for a centre frequency of 30 GHz, the fully embedded LC phase including a key component, shifter in stripline topology. The SPDT shows a good matching with |S11| = ?10 dB over a bandwidth of 18 %. It exhibits an insertion loss of 9 dB to 11 dB and an isolation between 22 dB to 32 dB. The continuous tuneability not only allows the selection of each preferred power splitting ratio at the output ports, but also a tuning of the centre frequency. The high insertion loss arises from a certain surface roughness as well as a decreased conductivity of the gold metallisation used.
关键词： single-pole double-throw (SPDT),low temperature co-fired ceramic (LTCC),Liquid crystal
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A 120 GHz LTCC Packaged Horn Antenna with a Radome and Soft Surface Structure
摘要： A 120 GHz step-profiled horn antenna integrated in low-temperature co-fired ceramic (LTCC) packages with a radome is presented in this paper. As an antenna-in-package (AiP) design, the proposed hollow horn structure is constructed by the cavities with several surrounding fences of vertical metallic vias in multilayer LTCC substrates. In consideration of the practical application, co-design with a thick cylindrical radome attached to the surface of the antenna is also studied. A planar soft surface structure in electromagnetics around the horn antenna is introduced so as to suppress the propagation of surface waves inside the radome and thus improve the gain performance. The simulated results indicate that more than 9 GHz bandwidth of -10 dB return loss and a gain of 12.56 dBi in the radiation direction at 0θ= ? are obtained.
关键词： horn antenna,soft surface,Antenna-in-package (AiP),low-temperature co-fired ceramic (LTCC),radome
更新于2025-09-04 15:30:14