Miniaturized Dual-Band Negative Group Delay Circuit Using Dual-Plane Defected Structures

In this letter, a design for a dual-band negative group delay circuit (NGDC) using dual-plane U-shaped defected structures is presented. The center frequency and group delay (GD) time of each band are separately controlled by a defected microstrip structure (DMS) and a defected ground structure (DGS) with resistors connected across the DMS and DGS slots. To verify the design concept, the NGDC is designed, fabricated, and compared with the circuit simulation. To get a wideband bandwidth, two NGDCs with different center frequencies are connected in a cascade design. From the measurements, the GD times of -4.54 ±0.6 ns and -4.20 ±0.5 ns are obtained at 3.46-3.58 GHz and 5.10-5.20 GHz, respectively.