Control and Measurement of Unintentional Electromagnetic Radiation

CHAPTER 8

MEASUREMENT OF UNINTENTIONAL RADIATIONS

8.1 INTRODUCTION

To determine the extent to which unintentional electromagnetic radiations must be reduced, they must first be measured. The primary purpose of this chapter is to make known what must be understood, and what must be done, for those measurements to be performed accurately and effectively. The measurement environment, the measurement setup, and certain aspects of the measurement procedure, all prescribed by various national and international agencies are described and analyzed. The basic theory behind the methods specified and those aspects of the measurements on which their accuracy largely depend are the topics of primary concern.

To measure electromagnetic radiations accurately, the receiving antennas used must be accurately calibrated, and the test site used must accurately simulate the ideal measurement environment. Therefore, attention will be focused here on (1) the characteristics of receiving antennas and how they can be accurately calibrated, (2) the characteristics of the ideal measurement environment and how its simulation by a given test site can be accurately validated, and (3) the appropriate use of both antennas and test sites in performing all of the measurements required, both to validate the test site and to minimize unintentional radiations.

Because they are used both for test site validation, and to search for and measure unintentional electromagnetic radiations, receiving antennas are first to ...