Low-complexity electronic circuit analogue of superluminal/subluminal phenomena that exhibits continuous tuning from negative to positive delay using a single Op-Amp circuit
We report and demonstrate an electronic circuit analogue of superluminal and subluminal phenomena whose Group Delay covers both the negative and positive range in a tunable manner but uses only a simple operational amplifier (Op-Amp) circuit. The circuit is a modified version of Kitano and Nakanishi's Negative Group Delay Circuit which covers only the negative group delay signal. By adding a simple low-pass RC circuit at the output of the Op-Amp, we can generate a continuous, tunable group delay range by simply varying the value of the capacitance of the circuit. We show mathematically and experimentally the following: (i) temporally advanced (negative group delay) signal, (ii) no-group delay signal, and (iii) typical delayed (retraction or lagged time) signal over a very narrow bandwidth as a demonstration of the circuit analogue of the superluminal and subluminal phenomena.