Reduction of Inductive Crosstalk Using Quadrupole Inductors

Innovative 8-shaped inductors integrated in an advanced BiCMOS technology

“…Devices description and layouts state of the art 8-shaped inductors are made of 2 consecutive twisted loops with a cross link at the centre of the structure, leading to equal magnetic distribution on each loop but with opposite polarities. a) From [2] b) From [4] c) From [6] Fig. 1 a) presents a higher deployed length in a smaller space compared to 0-shaped one.…”

“…Some publications have proposed comparison of 0-shaped (rectangular of octagonal layouts) and 8-shaped inductors implemented in VCO designs to demonstrate the benefit of 8-shaped inductors in terms of coupling reduction [3,4].…”

Low-phase-noise LC-VCO using high-Q 8-shaped inductor

“…The differential Q-factor (Qdd) exceeds 21 at 3 GHz and reaches a maximum of 26 around 5 GHz. These results are put into perspective with the 8-shaped inductor results from [2], giving a maximum Q-factor of around 14 at 6 GHz for 500 pH inductance. Table 1 provides a comparative results summary at 3.8 GHz, with slight discrepancies between measurements and 2.5D EM simulations using Momentum software.…”

“…Hence, proposing solutions to reduce the oscillator magnetic coupling without compromising its performance has become a real need in modern transceivers. For this task, employing 8-shaped coils in LC-VCOs has been invoked as a possible solution in a few recent works [1,2] mainly due to their interesting low magnetic coupling characteristics. However, 8-shaped inductors suffer in general from degraded Q-factor compared to standard O-shaped inductors, limiting therefore the phase noise performance.…”

Overlapped inductors and its application on a shared RF front-end in a MultiStandard IC

“…Thus we get two inductors with one inductor area. An 8-figure inductor is shown to be more immune to interference [5]. It is also used in chip-to-chip communication to separate channels [6].…”