By Josh Perry, Editor [email protected]
Researchers at the Georgia Institute of Technology (Atlanta, Ga.) have created a novel design that integrates antenna and electronics and boosts energy and spectrum efficiency for millimeter wave transmitters, which could improve modulation and reduce waste heat generation for potential 5G applications.
Image shows one of the packaged millimeter wave transmitters with antenna-electronics co-designed collaboratively by the Georgia Tech researchers. (Allison Carter/Georgia Tech)
According to a report from Georgia Tech, the hybrid devices allow for simultaneous optimization of the antennas and the electronics using conventional materials and integrated circuits, which means they can be manufactured and packaged by standard processes.
“Key to the new design is maintaining a high-energy efficiency regardless whether the device is operating at its peak or average output power,” the article explained. This avoids the challenge of conventional transmitters that are efficient at peak power but less efficient at lower power levels.
“Moreover, conventional transmitters often add the outputs from multiple electronics using lossy power combiner circuits, exacerbating the efficiency degradation,” the article continued.
Georgia Tech researchers combined the output power through a dual-feed loop antenna to achieve an outphasing operation that modulates and optimizes the output voltages and currents of power transmitters to ensure high energy efficiency at peak and average power.
The design will provide higher data rates within a fixed spectrum allocation, which has been a challenge faced by 5G researchers. The article noted, “The new designs have been implemented in 45-nanometer CMOS SOI IC devices and flip-chip packaged on high-frequency laminate boards, where testing has confirmed a minimum two-fold increase in energy efficiency.”
In addition, the design facilitates the creation of chips with hundreds or even thousands of transmitters and receivers working together as a system. This could enable 5G systems or be used to replace cables in large data centers, while expanding data rates and reducing cooling needs.
A proof-of-concept antenna-based outphasing transmitter was presented at the 2018 Radio Frequency Integrated Circuits Symposium in Philadelphia in June. The research has also been published at the 2017 and 2018 IEEE International Solid-State Circuits Conference (ISSCC).
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