Test and characterization of a plastic printed Ka-band slotted waveguide antenna

Abstract

With the Ka-band PolInSAR system, the German Aerospace Center is taking a first step towards SAR technology in Ka-band. Thereby, high demands on the mechanical accuracy of complex antenna components require new manufacturing methods such as 3D printing. Due to a higher coefficient of thermal expansion, an increased sensitivity of the plastic printed antenna against temperature changes is expected. The aim of this work is to investigate the behavior of two antenna prototypes manufactured of brass and plastic in the temperature range of airborne SAR systems. The investigation is carried out by simulations as well as by practical measurements. The theoretical investigation is performed to analyze the impact of temperature variation on the electrical performance of the prototypes. After the development of a suitable measuring setup, the characteristic of the antennas is measured at different temperatures. The comparison of a plastic printed and a classical milled antenna showed only minor differences in the electrical behavior and confirms that plastic is suitable for slotted waveguide antennas. Furthermore, a method to detect changes in antenna characteristics within a wide temperature range using simple measuring and processing methods could be introduced.