Low loss negative group delay circuit using self‐packaged suspended line.

A matched negative group delay (NGD) circuit with ultra‐low insertion loss by using self‐packaged multi‐layer suspended line is proposed. Two transmission paths with different electric‐lengths are used to produce positive phase slope, which would bring a negative group delay, while a coupled line is used for matching, and the commonly applied absorption resistors are not required. The NGD circuit has been fabricated and measured, and the design has been demonstrated with a measured NGD time of −2.84 ns, a NGD bandwidth of 34 MHz, a low insertion loss/signal attenuation (S21) of no more than 2.73 dB, and a S11 attenuation of about 27.8 dB. Both self‐packaging and metallized air cavities are used to reduce the wave leakage, and the multiple via holes usually used for electromagnetic shielding are saved, which greatly reduce the fabrication complexity. [ABSTRACT FROM AUTHOR]