Technician First: Teaching High Frequency Design As A Technological Enabler

This paper reports results of changes in student learning in a course in high frequency design. The course was revised from a traditional lecture/homework/summative examination format focusing on microwave theory to a project-based course using high frequency design techniques in the context of a realistic system design project. As wireless devices and networks continue to become more prevalent, it is more critical that electrical engineers of all sub-disciplines have a working knowledge of RF concepts and devices. Many courses on RF design require a significant prior knowledge of electromagnetics, however, limiting student access. To counter this trend a one semester course was developed designed explore ideas of teaching RF concepts as a “technological enabler” in order to give students who specialize in non-RF disciplines a basic understanding of RF system design. The participating faculty identified three critical areas that needed to be addressed sequentially to meet the goal of serving as a technological enabler: the ability to perform and understand RF measurements, a deep conceptual understanding of RF principles, and an understanding of RF system design principles. The first third of the course trained student as technicians so they were able to perform and understand RF measurements. At the conclusion of their training students were certified by measuring the performance of several RF devices using a spectrum analyzer and vector network analyzer. Conceptual understanding was addressed in the classroom by organizing the course around key RF concepts. To address system design principles during the last half of the semester the class designed a synthetic aperture radar (SAR) system. Teams of two students each designed passive components for the SAR system in an iterative approach that included simulation, testing, and then final assembly of the system. Student learning was evaluated by qualitative evaluation of videos taken during measurement tasks,and rubric based evaluation of student artifacts. As the speed of electronic devices moves ever higher, electromagnetic radiation plays a larger role in electronic design. Wireless networking, digital pulse propagation on integrated circuits and printed circuit boards, issues of electromagnetic interference and compatibility, and the technical and ethical issues of RFID tags all require some understanding of fundamental principles of high frequency (HF) engineering. At the undergraduate level, however, electromagnetics and, by association, HF design are often seen as complex and arcane subjects. Students’ first introduction is usually in a required electromagnetics course. Students must navigate through a conceptual maze of vector mathematics and analytic problems in which understanding of fundamental concepts is often less important than analytical tractability. While this mathematical development is vital for those students who will go on to get graduate degrees in electromagnetics, this approach does not serve the majority of students who need a working knowledge of HF devices and technology to understand how HF design impacts their own engineering sub-disciplines. To those not “initiated into the priesthood”, the principles of HF design are often seen as a “black art” 1 since analytic solutions are not tractable. However, the fundamental design principles are P ge 14166.2 straightforward and based on simple principles. So much so in fact, that experts familiar with HF design can often tell a good design principle from a bad simply by looking at devices. As technology makes greater use of GHz frequencies, it is no longer acceptable for HF design to be the art of a select few “high priests”. The thesis of this paper is that the burgeoning applications of HF devices and components requires a fundamental change in the way HF design and similar subjects are taught in engineering programs. The changes needed to address the way students learn HF design that are outlined in this paper are similar to those historically faced by its sister discipline in the OSU program, optics / photonics. The National Academy of Science in Harnessing Light: Optical Science and Engineering the 21 st Century 2 described the role of photonics in modern life: “Although optics is pervasive in modern life, its role is that of a technological enabler: It is essential, but typically it plays a supporting role in a larger system. Central issues for this field include the following: how to support and strengthen a field such as optics whose value is primarily enabling...” At the core of this project is the assumption that the fundamentals of HF design, similar to optics and photonics, have become so ubiquitous they now serve as a technological enabler. A technological enabler is any technology that impacts or enables progress in widely divergent areas such as industrial processes, medical and biological sciences, computers, communications, environmental, or military applications. Those engaged in these disparate fields need to understand and apply the enabling technology rather than have full mastery of the history and theoretical underpinnings. Despite the broad use of HF and microwave components in many disciplines, existing courses use lecture structured around one of the many available texts to emphasize mathematical development of fundamental principles. Such teaching methods help students gain an understanding of HF principles; a necessary but not sufficient goal of a technologically enabling course. Supporting and strengthening HF design additionally requires that engineering and other students see how HF design is applied to challenges in their discipline or future career. Ensuring future vitality requires that HF courses both enhance students’ chances HF-related employment as well as entice students to pursue graduate studies. Discussion of Planning Meetings To create a course on high frequency design techniques that could serve as wide an audience of students as possible, the three faculty and one graduate student involved in the course met on a regular basis (primarily) during a summer intercession to discuss the key requirements for such a course. The following paragraphs summarize the discussion of these individuals and serve to outline the framework around which the course was designed. The participants decided early in this project that keys to a course which would teach HF design as a technological enabler are transfer, retention of knowledge, and the understanding of, and relation between, different domains. Transfer describes the ability to take what has been learned and transfer it to new problems some time after information has been learned 3 . To enable students to transfer knowledge the faculty determined that the course needed to teach foundational knowledge and concepts, give students opportunities to monitor and measure their own understanding, and present problems in a context that is relevant. P ge 14166.3 Retention of knowledge is supported by a course structure that organizes knowledge around central concepts or technologies in a way that allows it to be recalled 4 . In order for students to retain what is learned and recall it for later use high frequency design content was taught the context in which it will be used, organized around core concepts or “big ideas”, and organized into small units that can be fit into a student’s overall framework of understanding. The domains of knowledge are analogous to Gardner’s theory of multiple intelligences 5 , but the three domains are different than those used by Gardner. Here the three domains reflect different types of skills or knowledge that each student must develop in order to actually apply what is learned and are drawn from work in developing a taxonomy of engineering skills 6 . Three separate, areas in which students need to gain competence are: 1) experimental skills that give students the ability to test what is known conceptually or analytically; 2) conceptual understanding of the overarching concepts that link seemingly unrelated problems; and 3) analytic skills to enable students to make design choices guided by analytic equations, verify their design through exact numerical simulations, and check the validity of their results by performing approximate “back of the envelope” calculations. To implement this vision of a course that serves as a technological enabler, the HF Design course was organized into three parallel tracks as shown in Figure 1, below. The tracks, with the duration and overlap shown at left, are training as a Figure 1: The overall organization of the high frequency design course showing components corresponding to each domain. SR = Status Report on the project and DR = Design Review. technician in the microwave lab, learning concepts in the lecture portion of the course, and design of a microwave system performed as part of a team. These three parallel tracks are mapped to the domains of experimental skills (technical training), conceptual understanding (teaching concepts), and application of analytic skills obtained through design and characterization of a microwave system. Each of these tracks will be described in detail later in this paper. The involved faculty felt that a key component of teaching HF design as a technological enabler was to design a microwave system made up of discrete components so that students would be able to obtain a larger, systems, viewpoint. After some discussion a synthetic aperture radar system was chosen since one faculty member had experience in the design of such systems, the system comprised both passive and active components, and uses concepts from both guided wave and free space propagation. Before the course was offered a SAR system was constructed by the graduate student using commercial, off-the-shelf components. The SAR system—and the students’ role in designing and building this system—is described in detail later in the paper. The last element di