Distributed transmission line negative group delay circuit with improved signal attenuation

In this letter, a novel design and implementation of a distributed negative group delay circuit (NGDC) with reduced signal attenuation is demonstrated. By inserting an additional transmission line Z₂ into the conventional NGDC, the proposed NGDC provides further design parameters in order to obtain the required differential-phase group delay (GD) time and help to reduce the signal attenuation. As a result, the number of gain compensating amplifiers can be reduced, which can contribute to the efficiency enhancement as well as the stable operation when integrated into the RF system. Both theory and experiment are provided to validate the proposed structure. From the experiment, for the same GD time of-7.9 ns, the signal attenuation of the proposed circuit is 16.5 dB, an improvement signal attenuation of the conventional circuit of 19.2 dB.