W-Band CMOS-PA - W-Band High Efficiency Power Amplifier in CMOS-Technology
Prof. Dr.-Ing. Georg Böck
Berlin Institute of Technology
Chair in Microwave Engineering
In the proposed project, the development of an integrated high efficiency broadband power amplifier (BBPA) covering the full W-band is intended. A 32 nm CMOS-process is foreseen for the fabrication of the PA. The proposed highly efficient BBPA is belonging to the most challenging components of ultra-high data rate communication systems at mm-wave frequencies.
Our proposal was established in close coordination and collaboration with TUHH, Prof. Jacob. The focus of the TUHH proposal is a wideband circularly polarized antenna and the subsequent integration of our CMOS PA to a system-in-package that forms the fundament for an integrated W-band transmitter. A low-cost 3D integration process should be used for integration and packaging of the CMOS PAs with a horn antenna based array to an integrated transmitter.
Behind our common project idea is the awareness, that the major problem concerning the realization of a high efficiency transmitting front-end at and beyond 100 GHz is the on-chip power combining loss. Free space combining using array antennas is a highly interesting alternative to overcome that issue.
The CMOS power amplifier should be based on a differential design without balun at the output. Instead, antenna elements with differential feeding ports (e.g. dipoles, ridged waveguides) should be applied. By that concept the source inductance of single ended designs and the loss of the output balun can be avoided at the same time.
Output power and efficiency of the PA should be improved by applying stacked transistors. Stacked transistor cells are voltage combiners that enhance the output impedance and hence reduce the current losses.
The final goal of the project is a highly efficient integrated W-band transmit module consisting of power amplifier and single or dual circular polarized antenna or small antenna array (e.g. 2x2).