When Time Delays Make More Sense Than Phase Shifts (.PDF Download)

Phase shifters and delay lines are commonly used components in many high-frequency systems, included for their signal-altering capabilities. Although a delay in the phase or the timing of a signal are essentially the same thing, phase shifters and delay lines are designed with different goals in mind: to provide signal adjustments in the frequency and time domains, respectively, over a design frequency range.

Phase shifters are usually designed for changes in insertion phase of as much as 360 deg., or one wavelength, at a maximum frequency of interest. When a greater amount of phase shift or delay is required at a particular frequency, the solution lies in an RF/microwave delay line, which is specified in terms of the delay time, rather than the phase shift, at a frequency of interest.