Planar Bias-tee Circuit Using Gradient-meander Line for Broad-bandwidth Application

This paper presented a new gradient-meander line based on an integrated and fully planar bias tee. In the case of constant total length, the use of gradient-meander layout improves the performance of inductance. The formula of gradient-meander line inductance is given. The simulation result is consistent with the formula. Inductors and bias-tee of different sizes are designed on 0.25um GaAs substrate. Electromagnetic simulations in the whole 20~100 GHz communication band, show that the optimized transition presents a return loss (RL) of at least 20 dB, an insertion loss (IL) of at most 2.6 dB, and a RF-to-DC path isolation (IS) of at least 15 dB.