Negative Group Delay Circuits and Applications: Feedforward Amplifiers, Phased-Array Antennas, Constant Phase Shifters, Non-Foster Elements, Interconnection Equalization, and Power Dividers

With the rapid development of newgeneration communication technology such as multiple-input/multiple-output technology, ultrawideband communication, and 5G technology, communication systems have higher requirements for the quality of signal transmissions. Achieving this quality requires attention not only to signal amplitude characteristics but also to phase characteristics because of the long delays and signal distortion that come with positive group delay (PGD). However, negative group delay (NGD) circuits are an effective way to compensate for PGD and decrease the variability of passband group delay.