Absorption and cross-talk in a multipixel receiving system with cold electron bolometers

In the article we compare two types of receiving pixels, based on cold electron bolometers, fabricated with different technology. Both pixels are designed for the 350 GHz frequency channel of the OLIMPO project. The first type of pixel is fabricated on a thin Si substrate, using an etching procedure, and the other on thick non-etched substrate. The individual antenna systems have been designed for both types of pixels. The investigation of absorption efficiency, amplitude-frequency characteristics and cross-talk has shown that the etched substrate has the highest absorption efficiency of 60% in the required frequency band and the lowest cross-talk of 0.2%. While the unetched 380 m substrate leads to a slightly smaller absorption efficiency and a slightly larger cross-talk, it allows for rigid structures and the exclusion of complex technological operations.