Analysis of quasi-optical power combiners by vector field measurements at 150 GHz

Abstract. A Two-dimensional quasi-optical power dividing/combining circuit has been experimentally investigated at 150 GHz. It consists of a rectangular horn antenna array as receiving/transmitting unit and a dual offset reflector setup to match the radiated field(s) to the pattern of the receiving antenna(s). To verify both design and adjustment of the quasi-optical circuit, electric field scans have been performed in selected planes and volumes of the setup. To measure the spatial electric field distribution, a vector field measurement system has been developed which operates in the frequency range between 148 GHz and 152 GHz. Excellent agreement between calculated and measured results for a horn antenna array approve the predicted results calculated under the physical optics approximation. Measured power dividing/combining efficiency of the passive structure of 63% for an inter-element spacing of 10$ \lambda$ indicates that the power combining principle is a suitable method up to submillimeter wavelengths.