A team of researchers from Purdue University have made a new highly efficient power amplifier for electronics that could help make possible next-generation cell phones, low-cost collision-avoidance radar for cars and lightweight microsatellites for communications.
5G mobile devices expected around 2019/2020 will require improved power amplifiers operating at very high frequencies. The new phones will be designed to download and transmit data and videos 100x faster than today's phones, with better coverage and lower power consumption.
Most power amplifiers in cell phones today are made on a GaAs process. At the moment this is the best process for providing a balance between cost, power and efficiency. However because they are developed on GaAs, they can not be integrated with the rest of the phone's silicon based chipsets based on CMOS.
The researchers at Purdue have developed a CMOS-based power amplifier which can be integrated with the rest of the phone's electronic chips, reducing manufacturing costs and power consumption while boosting performance. Silicon is much less expensive than gallium arsenide, more reliable and has a longer lifespan and if you have everything on one chip it is also easier to test and maintain.
The researchers created this new type of amplifier using a high-performance type of CMOS technology called silicon on insulator (SOI). This amplifier design has several silicon transistors stacked together and reduces the number of metal interconnections normally needed between transistors, reducing "parasitic capacitance," which hinders performance and can lead to damage to electronic circuits.
They have merged transistors so they are using less metallization around the device, and that way they have reduced the capacitance and have achieved higher efficiencies. They are trying to eliminate metallization between transistors. The amplifier built using this process achieves an efficiency of 40 percent, which is comparable to amplifiers made of gallium arsenide. It is the highest efficiency CMOS power amplifier that has been developed in the frequency range needed for 5G cell phones and next-generation radars.
These amplifiers could bring low-cost collision-avoidance radars for cars and electronics for lightweight communications microsatellites. These CMOS amplifiers could allow researchers to design microsatellites that are one-hundredth the weight of today's technology.
Findings are detailed in two papers, one to be presented during the IEEE International Microwave Symposium on May 24 (Today) in San Francisco, authored by former doctoral student Sultan R. Helmi, who has graduated, and Saeed Mohammadi. They also authored another paper with former doctoral student Jing-Hwa Chen to appear in a future issue of the journal IEEE Transactions on Microwave Theory and Techniques.
Three U.S. patents related to the amplifier have been issued. The research was funded partially by the U.S. Defense Advanced Research Projects Agency. The researchers are currently working on a new version of the amplifier that is twice as powerful. Further work will be needed to integrate the amplifier into a cell phone chip.
