Enhanced group delay of microstrip-line-based dispersive delay lines with LC resonant circuits for real-time analog signal processing

Large group delay swing against frequencies, provided by series connection of quarter-wavelength coupled lines, is useful to design real-time analog Fourier transformers. However, due to lack of strong coupling, open-aired microstrip line architecture could not be used to design these devices so far. This paper proposes novel microstrip-line-based dispersive delay lines (DDLs) with LC resonant circuits. Comparing with the conventional DDL without LC circuits, larger group delay can be generated. In demonstration, a group delay peak around 3.0 ns is generated successfully with small footprints of 16.6 × 3.65 mm
²
.