Right angle corners on printed circuit board traces, time and frequency domain analysis

Abstract

In order to study how transmission lines function, consideration must be given to investigating both time and frequency domain characteristics of the network. When a signal propagates through a transmission line, commonly identified as a PCB trace, the mode of transmission is that of an electromagnetic wave, not voltage, current or electrons. Maxwell's equations describe the characteristics of this electromagnetic wave. A closed loop circuit allows a signal to travel from source-to-load along with a mandatory return path from load-to-source. This circuit will contain both DC and AC (RF) components simultaneously. Design engineers usually consider only propagation delay, frequency of operation, capacitive overheads, dielectric losses, impedance control, and similar parameters during schematic design. When a signal propagates down a transmission line (trace) in the time domain, a frequency domain component is simultaneously observed with appropriate instrumentation. The following are examined: 1. Effects of a signal propagating down a transmission line (trace) in the time domain. 2. Effects of trace width and magnetic flux distribution created with various corner configurations. 3. Radiated emissions with and without an RF return path. 4. The frequency at which corners play a significant role in the creation of RF energy.