Adaptive Dummy-gate (field-plate) Bias Technique for RF LDMOSFETs


Lehigh University has developed an adaptive field- plate (dummy-gate) bias technique for improved performance in RF-LDMOSFETs to be used in cellular base-station. Initial tests of this technique show a 70% improvement in the maximum output power and 10% improvements in the efficiency of the device. The field-gate is present in most commercial RF-LDMOSFETs but it is tied to the static ground potential. It’s presence reduced harmful capacitance effects and suppressed long-term degradation. This invention uncovers a method of applying suitable modulated bias to the field-plate to improve efficiency and output power.


The increase in output power will translate to a greater coverage area for cellular base stations and the improved efficiency will reduce the heat dissipation and related reliability problems. These improvements will lead to clearer and stronger signal on a consumer’s cell-phone and lower maintenance and deployment costs for the cellular service provider.


Lehigh Tech ID# 090506-01



The mobile phone market is huge, with over 5.3 billion subscribers. That is 77% of the world population and encompasses a $240 billion market. The mobile phone industry is growing with the largest growth areas expected to be seen in China, India and Japan. While coverage has expanded each year and service providers are marketing greater coverage for their customers, there is still a demand among consumers for better performing technologies with greater service areas. Additionally market players are always looking to reduce cost as the provider market is becoming more competitive. [1]



[1] “Global Mobile Statistics 2011.” November 2011. MobiThinking web site. (accessed November 21, 2011).



Lehigh University is currently looking for co-development support for this technology.

App Type Country Serial No. Patent No. File Date Issued Date Expire Date
Utility United States 12/518,724 7,986,186 6/11/2009 7/26/2011 1/18/2028
For Information, Contact:
Alan Snyder
VP, Research & Grad Programs
Lehigh University
James Hwang
Marvin Marbell
Adaptive Bias
RF power amplifiers