TABLE OF CONTENTS The unit of power is the watt (W), which is established by the International System of Units (SI). One watt is one joule per second. If you are new to RF, then you might be used to thinking of power in terms of voltage or current. For example, power equals the voltage squared divided by the resistance. This is really only valid at dc or near-dc frequency levels. In fact, it is interesting to note that voltage is actually derived from the watt and not vice versa, which is a common misnomer. A volt is 1W per ampere (see Chapter 6 for many of the same definitions presented from a mixed-signal point of view).
