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The purpose of this paper is to help high frequency circuit designers understand how to choose the best permittivity value for a laminate material for accurate modeling.

In this paper, experimental measurements of the performance of simple circuits are compared to various mathematical and software models.

Higher permittivity values were obtained using samples with bonded copper foil compared to samples etched free of foil. These higher values yielded better agreement between measured and modelled performance using current automated design software. High profile foil on thin laminates was found to increase the surface impedance of the conductor and change the propagation constant and apparent permittivity of the laminate by 15 percent or more. It was also demonstrated that, under some circumstances, the anisotropy of the substrate could result in differences in measured and modelled performance.

Only a limited number of circuit laminate materials were closely examined. Future work should include a wider variety of laminates.

The paper details the magnitude of the effects of test method, conductor profile and substrate anisotropy on the values of a material's permittivity best suited for circuit design purposes.

This chapter describes the possibilities for fusing ethnography and evaluation to transform educational inquiry and educational entities (programs, systems, and policies). The central question explored is, how do we best pursue work connecting evaluation and ethnography to fulfill our commitments to diversity, justice, and cultural responsiveness in educational spaces, to make tangible transformative change? With 40 years of literature on ethnography-evaluation connections as a foundation, this chapter describes three coalescing themes: transformative, intersectional, and comparative. These themes are proposed as valuable for guiding contemporary educational inquiry that serves social justice. The transformative theme denotes educational inquiry in which the researcher or evaluator ethically collects data, makes defensible interpretations, and facilitates social change in collaboration with others. Doing transformative work that meaningfully fuses ethnography and evaluation rests on essential factors like time, values engagement, collaboration, and self-work. The intersectional theme describes intersectionality as an evolving analytical framework that promotes social problem-solving and learning via investigating the significance of intersecting social identities in (a) how people's lives are shaped, (b) their access to power across circumstances, and (c) their everyday experiences of subordination and discrimination. Finally, the comparative theme refers to sensibilities and practices gleaned from the interdisciplinary and transnational field of comparative education, including developing comparative cultural understanding and analyzing complex systems in one's inquiry projects. Across themes, this chapter emphasizes positionality, responsibility, and theory-bridging to make sense of the uses of ethnographic concepts and practices in transformative evaluation work in educational spaces.