Abstract
In this study, the authors will investigate the insertion loss (IL) of the broadband 8-way power combiner used in their millimetre-wave power amplifier (PA) design. By treating this combiner as impedance transformer under resistor-capacitor (RC)-loading condition, both the characteristic impedance and electrical length of the constituting metal lines can be obtained, where the much shorter line length suggests wider bandwidth and lower IL. However, proper loss analysis must take into account the multi-reflection of voltage wave along these mismatched transmission lines, i.e. the use of the power attenuation expression is just not accurate enough. With their derived equations, it shows that the IL of their proposed 8-way combiner can be as low as 0.92 dB at 94 GHz, which is much smaller than the 1.5 dB for the conventional quarter-wavelength combiner. Mathematics for the IL of the drain-bias shunt stub and the output DC-blocking capacitor has also been derived. As a demonstration, a 77–110 GHz 40 nm-complementary metal–oxide–semiconductor PA made of cascode transistors is then designed that has more than 18 dB gain, and its OP1 dB is around 13 dBm across the whole frequency range.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.