Broadband src='/images/tex/19873.gif' alt='Gm'> -Boosted Differential HBT Doublers With Transformer Balun

摘要

Broadband monolithic InGaP HBT frequency doublers for $K$-band application have been developed. The designs employ a $Gm$ -boosted differential common-base configuration using either capacitive or transformer-based coupling between base and emitters. To the authors' best knowledge, these are the first frequency doublers utilizing the $Gm$-boosted configuration and the result demonstrate larger bandwidth and higher output power than any previously reported frequency doublers. The design with cross-coupled capacitors presents a fundamental rejection better than 20 dB over a 100% 3-dB bandwidth, extending from 6 to 18 GHz. The transformer-coupled design has about 15-dB fundamental rejection over a slightly narrower bandwidth extending from 7 to 16 GHz. Both doublers have conversion gain peaking at more than $-{hbox {0.8 dB}}$ and output power ${P{rm sat}}> 13~{hbox{dBm}}$ . The designs are also very compact with chip sizes less than ${hbox {0.5 mm}}^{2}$.