Passive Coupling Balance Scheme for Long Traveling Complex Differential Signals

Tech ID: 29224 / UC Case 2016-979-0


Researchers at the University of California, Davis have developed a passive coupling balance technique to suppress signal mismatches for long traveling N-pair complex differential signals.

Full Description

As signal frequencies increase, mutual coupling between signals gives rise to a variety of problems including: increased signal crosstalk, increased in-phase and quadrature (IQ) imbalances of complex signals and co-channel interference. There are several ways to suppress the signal mismatches but these methods not only require specific circuit designs and complex algorithms to accommodate the unexpected mismatches, they also slow down the processing of the entire signal.

Researchers at the University of California, Davis have developed a passive coupling balance scheme for differential signals by using twisting schemes. The technique passively suppresses mismatches, requiring no additional circuitry. It exhibits sufficient suppression even at higher frequencies without requiring additional power by scaling the structure. With a simple fabrication process, this technique works well for multi-phase signaling applications.


  • Digital communications systems
  • Radar systems
  • Improved 4G antennas
  • Multiphase Voltage-controlled Oscillators (VCOs)
  • Quadrature processing


  • Utilizes a passive method to decrease quadrature signal mismatches
  • Allows for the pairs to be pulled away at distances that still retain robustness
  • Does not require additional circuitry

Patent Status

Country Type Number Dated Case
United States Of America Issued Patent 10,426,023 09/24/2019 2016-979


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  • Gu, Qun
  • Li, Jinbo

Other Information


image rejection ratio, IMRR, IMR, quadrature signal accuracy, transmitter, multi-phase signal processing, IQ, I/Q, n-pair, complex signals, long travel, digital circuits, high frequency signals, twisting scheme, passive coupling

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