The shrinkage of Low Temperature Co-fired Ceramics (LTCC) during firing is one of the most difficult features to control in LTCC fabrication, as many factors may impact on the result. The shrinkage ...given by the tape manufacturer is not perfectly transposable to a production environment where preparation, use and equipment is not in exact accordance. Thus, predictable shrinkage models are of main importance in order to fabricate LTCC devices according to specifications. The objective of this work is to develop such models for the Ferro L8 tape using the powerful Design of Experiments (DOE) technique. Four factors are varied; the stack thickness, the device surface, the applied pressure and the temperature during lamination. Other factors such as operator, lamination time or firing profile are kept to a fixed value during these experiments. The result variables are lamination quality and x, y and z-direction shrinkage. Lamination quality is found to be mainly impacted by the interaction between the stack thickness and the surface area of the stack, while for the z-direction shrinkage this interaction together with lamination temperature are significant factors and finally for the lateral shrinkage the main effects stack thickness, surface area and temperature are significant. Numerical models for shrinkage in z- and lateral directions are established. This work enforces the understanding of the shrinkage of LTCC and permits for the Ferro L8 users correctly compensate the layout for shrinkage.
The paper presents a metamaterial based LTCC compressed Luneburg lens antenna for wireless communications. The antenna is designed at 60 GHz to utilize the unlicensed mm-wave spectrum available for ...short-range high-data-rate communications. The gradient index compressed Luneburg lens antenna is designed using the quasi-conformal transformation optics method. The design of the antenna is fully compliant with the standard LTCC process with a high-permittivity host material. The diameter of the antenna is 19 mm and the thickness is less than 2 mm. The peak antenna gain at 60 GHz of 16 dBi is demonstrated. Beam scanning capacity is demonstrated with 1 dB scan loss within ±25 degree field of view.
In this paper, a new design of a low-profile and multilayer broadband microstrip antenna is proposed for millimeter-wave applications at 60 GHz. The antenna is a metamaterial inspired structure that ...consists of a non-uniform octagon shape radiating element on the top of six layers of substrate and a periodic structure at the second layer. The proposed antenna geometry is designed using Low Temperature Co-Fired Ceramic (LTCC) technology for 3D multilayer vertical integration. This antenna achieves 24.16 % of bandwidth ranging from 55.5 GHz to 70 GHz, with a peak gain of 5.1 dBi at 60 GHz. HFSS is used for design and simulation of this LTCC based broadband antenna. Three prototypes are fabricated for measurement and a good agreement of numerical and practical results is obtained which makes this antenna very attractive for the use in future wireless communication systems.
Passive component development in LTCC Karnfelt, Camilla
2017 21st European Microelectronics and Packaging Conference (EMPC) & Exhibition,
2017-Sept.
Conference Proceeding
Odprti dostop
Passive components integrated in Low Temperature Co-fired Ceramics (LTCC) are of interest for highly integrated microwave and millimeter-wave modules. Metal Insulator Metal and Interdigital ...capacitors as well as spiral inductors with a maximum surface of 1 mm × 1 mm were designed, fabricated and tested using the ESL41060 tape material. Capacitive and inductive values, the Self Resonance Frequency and the Q-value for these items were found.
The high cost and size of circulators have always been the main drawbacks of these components. Low temperature co-fired ceramics technology (LTCC) could reduce the cost by simplifying the ...manufacturing process. Two new ferrites with low sintering temperature were developed and evaluated: a garnet-based ferrite with a high permittivity and a spinel-based ferrite with a high saturation magnetization. Two circulators based on these ferrites have been designed using coupled magnetostatic and electromagnetic simulations and fabricated. Their insertion losses and sizes are very close. The high magnetization of the spinel ferrite allows a bandwidth twice as high as the garnet-based circulator. Both circulators showed good performance and demonstrate that low temperature co-fired ceramics technology can be used for the collective realization of low cost circulators.
A simple technique for direct extraction of junction temperature and thermal resistance for MESFET and HEMT FET is proposed and experimentally evaluated. The techniques were applied for thermal ...resistance extraction of the mHEMT devices in a microstrip three-stage amplifier before and after flip chip assembly.
Purpose - Liquid Crystal Polymer (LCP) materials are considered to be promising substrates for wireless applications because of their excellent properties. The purpose of this paper is to describe ...now a novel and compact microstrip ultra-wideband bandpass filter (UWB BPF) with ultra-fine conductor traces working over 22 to 29 GHz is fabricated on LCP substrates.Design methodology approach - Using standard processing technology, such as photolithography, plasma pretreatment, sputter deposition and wet etching, a microstrip UWB BPF is fabricated on LCP substrates. In order to obtain better adhesion between LCP substrate and copper, the oxygen plasma pretreatment of the LCP substrate surface and a thin titanium adhesion layer are introduced before a copper layer is sputter-deposited onto the substrate.Findings - The measured and the simulated results agree well. The measured insertion loss is about 8 dB in the passband of the bandpass filter, which is a little high compared to the simulated result (∼5 dB). The out of band performance at both the high frequency and low frequency is very good, almost higher than 35 dB.Originality value - This paper presents the realization of (UWB BPF) working over 22 to 29 GHz based on an LCP substrate, which demonstrates the feasibility of the application of the LCP substrate in RF wireless systems and also gives some useful information for later research.
A grid array antenna working around 145 GHz is proposed in this paper. The antenna is built on liquid crystal polymer (LCP) and designed for the Formula Omitted-band antenna-in-package application. ...The intrinsic softness of the LCP material is a limiting factor of the antenn's aperture size. A 0.5-mm-thick copper core is used to compensate. By doing this, the rigidness of the antenna is effectively improved, compared with an antenna without the copper core. Wet etching is used to realize the patterns on the top and bottom conductor. Compared with a low-temperature cofired ceramic counterpart, we obtain a considerable cost reduction with acceptable performance. The proposed antenna has an impedance bandwidth of 136-157 GHz, a maximum gain of 14.5 dBi at 146 GHz, and vertical beams in the broadside direction between 141 and 149 GHz. The fabrication procedures of the antennas are introduced, and a parametric study is carried out, which shows the antenn's robustness against fabrication tolerances, such as the not-well-controlled etching rate and the substrate surface roughness. This makes the antenna a promising solution for mass production.
This paper presents work on micro heat pipe (MHP) fabrication in Low Temperature Cofired Ceramics (LTCC) modules for cooling purpose. The MHPs are fabricated in a 10 layer structure using ESL41020 ...tape. Different fabrication settings have been tested to minimize swelling and groove deformation. The best result is obtained by using fugitive tape, extended firing profile, and hot lamination at 50°C for 5 minutes with 70 bar pressure.
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