A Broadband Switch-Less Bi-Directional Amplifier with Negative-Group-Delay Matching Circuits

A broadband switch-less bi-directional low noise amplifier based on negative group delay (NGD) matching circuits with a non-Foster characteristic is proposed. To validate the feasibility, two circuits were designed and compared, which are matched by NGD circuits and traditional lumped elements respectively. The structure proposed in this paper has a measured relative bandwidth (RBW) of 32.6% rather than 5.1% for the traditional one. From 797 MHz to 1095 MHz, the input and output return losses (RL) are more than 10 dB with a noise factor (NF) of about 3.5 dB and peak gain of 12.2 dB. Meanwhile, the reverse isolation and stability factor (SF) are greater than 20 dB and 1, respectively. The group delay (GD) value is 0.5 ns +/- 0.25 ns in the operating frequency band, which is much flatter and lower compared to that of the traditional one.