Representation/Effect of a delay element in the frequency domain?
A pure delay will not change the bandwidth of the filter at all. A delay in the frequency domain is a phase shift proportional to frequency.

This is explained much better in this question from the DSP stack exchange.

https://dsp.stackexchange.com/questions/509/what-effect-does-a-delay-in-the-time-domain-have-in-the-frequency-domain