a. Above what frequency will the radiated emission of Problem 12.6 begin to fall off as a result of the loop no longer being small?
b. What will be the slope of the fall off?
Problem 12.6
A PCB trace 4 in long and spaced 0.062 in from the return conductor is carrying a 10-MHz, 3.18-ns rise time clock signal. Assume the current in the loop is 50 mA.
a. Determine the radiated field strength in dB μV/m at the fundamental frequency, when measured at a distance of 3 m from the board.
b. Plot the envelope of the radiated emission from 10 to 350 MHz.
c. What is the worst-case margin against the FCC Class B limit, and at what frequency does it occur?