Adaptive Dummy-gate (field-plate) Bias Technique for RF LDMOSFETs (Technology#: 090506-01)


This invention uncovers a method of applying a suitable modulated bias to the dummy-gate (or field-plate) in RF-LDMOSFETs to improve the efficiency and output power. Initial tests of this technique show a 60% improvement in the maximum output power, and a 10% improvement in the efficiency of the device. The increase in output power will translate to a greater coverage area for cellular base stations that use this transistor, and the improved efficiency will reduce the heat dissipation and related reliability problems. These improvements will lead to a clearer and stronger signal on the consumer’s cell-phone and lower maintenance and deployment costs for the cellular service provider.


An adaptive dummy-gate bias provides improved output power and efficiency over the source-connected dummy-gate setup.  It is simpler to implement than an adaptive drain bias due to the low current requirements of the dummy-gate. Additionally, an adaptive dummy-gate bias can be combined with an adaptive drain bias to improve the achievable maximum drain efficiency and RF output power to increase coverage area for cellular base stations.

  • Cellular base stations
  • Other high power RF applications to increase output power and efficiency


A US national phase patent cooperation treaty (PCT) application has been filed.

James Hwang's Lehigh Page
Patent Information:
For Information, Contact:
Yatin Karpe
Associate Director
Lehigh University
James Hwang
Marvin Marbell
Adaptive Bias
RF power amplifiers
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