Reconfigurable RF Dispersive Delay Circuits by Stepped Impedance Shunt Stubs

A design of RF dispersive delay circuits with both convex and concave delay profiles using stepped impedance stubs are presented in this brief. A transmission line model is used to analyze the structure and to obtain design equations. Three prototypes with different delay profiles are fabricated to validate the proposed technique. Next, a reconfigurable delay line with switchable delay profiles is presented. However, because of its parasitic, PIN diodes used for switching change the delay profile. A procedure is described to compensate the loading effect of PIN diodes. A prototype is fabricated. In all the cases, good agreement is obtained among the predicted and measured results. A comparison with recent works shows that present unit provides highest peak group delay with minimum insertion loss. The dispersive delay lines operate as a linear device at least up to 23 dBm of input power.