Thermal stabilized front-end PCB with active cold calibration load for L-band radiometer

In this paper, the thermally stabilized front-end of an L-band total power receiver is presented. Applications on the L-band have become one of the most important focus points in the field of passive microwave remote sensing. Measuring environmental parameters such as ocean salinity and soil moisture remain a challenge, posing strict requirements to instrument performance. For traditional radiometers, especially the stability of front-end components is critical. The principle of the stabilization technique and the actual design are described. The design also features an on-board active cold load for calibration purposes. The presented technique aims to stabilize the front-end section PCB with heaters to sub 0.05 C level.