Making communication devices smaller, lighter, and cheaper has been the driving force behind the development of new technologies which have made the cellular phones and wireless networks we now take for granted possible. The frequent emphasis on miniaturization particularly has required the development of a variety of new approaches to creating communications circuits. One such technology that has attracted a great deal of attention in recent years is passives that are embedded into the package of communications integrated circuits. Using these devices reduces the amount of surface area required to implement a communications device, in addition to potentially improving performance and making them cost less. One area of application which is immediately obvious is the RF filtering which is required in communication devices.
The primary contribution of the present work is to establish a procedure for using such embedded passives to implement RF filters. While a large body of work has been previously devoted to the modeling and creation of individual embedded passives, the challenge of combining them into functional networks for use in communications system has not yet been the subject of a significant amount of academic analysis. By consolidating the knowledge gained by previous work concerning the modeling and optimization of embedded passives, the present work attempts to formulate an optimized procedure for creating embedded passive filter networks.
The present work presents the design and implementation of LC ladder filters for microwave frequencies using passives embedded in an organic substrate provided by Intel Corporation. The work presents an efficient and accurate methodology for the design and implementation of such filters in a limited footprint area, with an emphasis on creating a straightforward, fast design procedure. For both embedded passive inductors and capacitors a parameterized three dimensional model suitable for use in a fullwave solver has been developed. An exhaustive documentation of the simulation parameters used to simulate these structures is provided in order to assist others in repeating the work presented here.
In order to create embedded filters, libraries spanning the design space of both embedded inductors and capacitors have been formed. Inductors with different numbers of turns, trace widths, trace spacing, and inner diameters have been simulated from 1 to 10 GHz and analyzed to obtain the inductance, self resonant frequency, Q, and parasitic effects. Capacitors with plate areas ranging from a minimum size up to 1 mm" are also simulated and empirical formulas for their capacitance, resistance and inductance are provided.
Based on this, a design methodology is proposed and documented. The design methodology includes compensation for the coupling effects that exist between embedded passives placed in close proximity to one another. Based on the simulated coupling effects suggestions for layout are made. A design procedure developed in this work has been applied to a three pole and five pole low pass filters. The filters' characteristics show an excellent agreement the response of the LC ladder filter. Finally the work presents a study of some the effects of manufacturing tolerances on filter construction. Based on the preliminary findings of the investigation the most detrimental effects are determined and further work to explore these issues is suggested.
Library of Congress Subject Headings
Wireless communication systems--Design and construction; Electric filters, Passive; Microwave filters; Microwave circuits; Electric inductors
Electrical Engineering (MS)
Department, Program, or Center
Electrical Engineering (KGCOE)
Lambert, William, "Compact Realizations of Embedded Filters in Organic Substrates" (2005). Thesis. Rochester Institute of Technology. Accessed from
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