Compact Ultra-Broadband Power Dividers with Integrated Resistors

This paper describes the development of ultra-broadband compact power dividers for the frequency range from 2 to 40 GHz. A multi-section approach with reduced line lengths of the successive sections is used to achieve this large bandwidth at a minimal size. The resistors needed for an acceptable isolation are manufactured by lithographically structuring a conductive paste on top of microstrip lines. Thus, the entire device is planar and enables the integration in multilayer printed circuit board (PCB) stacks. The design is demonstrated with a three (five) section divider, which occupies less than 5 mm(2) (16 mm(2)) of surface area. The insertion loss is below 3.8 dB (4.7 dB) from 1 to 40 GHz, while all ports exhibit more than 10 dB match. The isolation exceeds 10 dB above 6 GHz (2.5 GHz).