Slotted-Waveguide Antenna Array Development by Means of Complementarity оf CST Microwave Studio and Compass 3D Programs

Abstract

The main steps of the methodology for complex slotted-waveguide antenna arrays development using the complementary application of the COMPASS 3D design program and electromagnetic modeling CST Microwave Studio are considered. The presentation of the technique steps is carried out on the example of a structurally complex slotted-waveguide antenna array of the Ka-band with dimensions (117 mm ´ 30 mm) and two-dimensional array of 64 (2 ´ 8 ´ 4) slotted emitters. To facilitate the synthesis of the design parameters of such grids, it is proposed to use a three-stage process: 1) design of slotted antenna emitting modules with adjustment to a given operation frequency range; 2) development of harmonized multichannel power divider for them; 3) combining the antenna modules and the branched power divider into an effective antenna array with additional adjustment of their coordination parameters. According to this sequence, in the illustrated example, on the first step, the antenna emitter module with four slits is designed in the CST Microwave Studio program. Afterwards, on the second stage, a complex multi-channel waveguide power divider was designed. It is first drawn in COMPASS 3D and then imported and analysed in CST Microwave Studio. On the final third stage, the entire slotted-waveguide antenna array was assembled and simulated in CST Microwave Studio. At the same time, the obtained radiation pattern of the antenna array, the functions of electromagnetic field distribution in the waveguide path and other electromagnetic characteristics corresponded to the required ones. Equally, there was a slight shift in the standing wave ratio (SWR) of the operating frequency matching, as well as some deterioration in the SWR. This is explained by the fact that the links between the models of antenna emitters and the waveguide power distributor were carried out "in ideal ports". Meanwhile, the real values of the input resistances in these planes of the assembled structure are somewhat different from the ideal ones. Therefore, to complete the process of structural synthesis of the antenna-slot array, two approaches should be used: 1) it is better to complete design parameter optimization according to the criterion of improving the harmonization, if required to shift the operating frequency, 2) to reduce the SWR value, it is better to improve the coordination of the antenna array at its input by adjusting the matching device.