Metamaterial transmission lines can be realized as a combination of transmission line sections with positive and negative dispersion. Such lines, which are also known as right-and left-handed transmission lines, exhibit different dispersion characteristics. Compared to homogeneous networks, the use of cascaded line sections gives additional degrees of freedom for improving the performance of microwave devices. For the design process, LC-equivalents of the right-and left-handed transmission line sections are used. This facilitates the consideration of tunable capacitors, e.g., varactor diodes, to provide frequency tuning of the devices. At the same time, the geometrical dimensions of the devices can be drastically reduced. This paper presents the results of simulation and experimental investigation of a miniature rat-race-ring and a dual-band filter free of spurious response, both manufactured as fully-integrated ceramic multilayer modules based on Low-Temperature Co-fired Ceramics. The design of tunable versions of these devices is also discussed.
Low-temperature co-fired ceramic (LTCC) are widely acknowledged for wide-band and microwave circuits. Within the project consortium KERAMIS, implementation of higher functionality in LTCC substrates is being investigated. Among the applications considered are a 4 × 4 switch matrix [1], voltage-controlled oscillators [2], and amplifiers for multimedia satellite communications working in Ka-band. In order to add more functionality (e.g., filters, couplers) in LTCC, current patterning limits of line width and line separation need to be extended. Four different technologies were considered for higher resolution: a) fine-line printing technology with special screens, b) photo-imageable pastes, c) etching of thick-film conductors (co- and post-fired), and d) thin films on LTCC. Evaluation of patterning technologies is based on a test coupon that was designed and manufactured by the consortium members. The artwork contains lines, line transitions, ring resonators (microstrip and stripline), edge-coupled filters, DC blocking structures, and various lines for DC resistance testing. The smallest gap definition is 50 μm. Two substrate materials, Du Pont tapes 951 and 943, are included in the study. In addition to the main frequency band of interest in the project (17–22 GHz), these structures have been characterized up to 50 GHz. Electrical results are correlated to physical measurements of the structures (line width, spaces, and tolerances) and are evaluated with respect to performance, manufacturability, and yield. Results show excellent performance for screen-printed structures and demonstrated the importance of mask tuning to achieve optimum resolution (under etching etc.).
The combination of right-handed and left-handed transmission line sections enables a novel design strategy for miniature dualband resonators and filters in the GHz-range with a wide stopband at higher frequencies. The design procedure is described, and experimental Figure 4 RF spectra for (a) down-and (b) uplink data signalsFigure 5 Measured BER curves for downlink data and uplink one Figure 4 The multilayer LTCC structure of the dual-band two-pole filter, (b) simulated and measured performance of the five nominally identical samples of the filter in the narrow frequency range, (c) simulated and measured performance of the five nominally identical samples of the filter in the wide frequency range 632 Applications of right/left handed and resonant left handed transmission lines for microwave circuit design,
Embedded ceramic coils stand out because of their excellent dielectric, thermal, and RF properties. However the relatively high sheet resistance (low thickness) of printed thick-film conductors restricts their functionality for applications where current values of several amps are needed. Using embossed structures it is possible to manufacture conductors with increased thickness and low resistance on LTCC tapes. The manufacturing process for wide conductors with high dimensional accuracy was shown in previous publications. In this work fine line embossed structures with line widths and spaces of 50 and 75 μm respectively were realized. The cross section of the embossed channels was about 50 μm. The fine line screen printing, stencil printing, and the photo definable Fodel® processes were used to fill the small structures with thick-film ink. The whole process was used to manufacture several types of low resistance coils in LTCC that can be used for current values up to approximately 3 A. They were realized as embedded as well as SMD components. Thus, the functionality of LTCC modules and LTCC SMD coils was increased. In this paper, the filling and patterning characteristics of all structuring methods are compared and the results discussed. Furthermore, the advantages of this process are shown by electrical, thermal, and RF measurements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.