Study On Thermal Homology Design And Optimization Of The Antenna Structure For Submillimeter-wave Telescopes

The submillimeter band(wavelength=0.1～1 mm)is a unique window for us to understand the Universe and plays an irreplaceable role in many fields of astrophysics,including star formation,active galactic nuclei,cosmology and so on.Submillimeterwave telescope is a key equipment for these fields of scientific research.The performance of a submillimeter-wave telescope is heavily dependent on its antenna.However,the thermal effect is an important factor that affects the performance of submillimeterwave antennas.In particular,due to the difference in temperature or material parameters(the coefficient of thermal expansion)between the major subsystems of submillimeterwave telescopes,complex thermal deformation coupling occurs at the connection of the substructures,resulting in severe degeneration of the antenna reflective surface accuracy and antenna pointing accuracy.Eliminating the effects of thermal deformation coupling on antenna reflective surface accuracy and other performance is one of the difficult issues in the study of the submillimeter-wave telescope antenna technology.To solve this issue,firstly a mathematical model for the thermal homology design of the submillimeter-wave telescope antennas was derived,which provides a theoretical basis for the thermal homology design of structures,as well as the theory and method of structural thermal homology design.Second,three-dimensional parametric finite element models of various submillimeter-wave telescopes with different apertures,such as the 1.2 m submillimeter-wave telescope,5 m Dome A Terahertz Explorer(DATE5),and Caltech Submillimeter Observatory(CSO)10.4 m submillimeter-wave telescope,are independently constructed or reconstructed.These telescopes have been used to study the complex thermal deformation coupling of their antenna substructure systems due to the discrepancies in temperature or material parameters of subsystems,and various types of thermally conformal structures have been designed according to the differences in their antenna structures.Furthermore,zero-order optimization,first-order optimization,genetic algorithms and topology optimization are adopted to deeply optimize these various antenna structures with different thermal homology structures.An optimization method for the performance of submillimeter-wave telescope antennas has been developed to improve the compatibility between the thermal homology structure and the inherent structural system of these telescopes,and satisfactory design results are obtained.Simultaneously,the thermal homology structure of the 1.2 m submillimeter telescope has been presented.The studies have shown that the experimental results agree well with the theoretical design optimization results.In conclusion,a method for the thermal homology design of the transition structure of submillimeter-wave telescope antennas has been developed.Combining a variety of optimization methods,a number of optimization methods of thermal homology structures have been proposed,and the overall structure of submillimeter telescope antennas of different apertures have been thoroughly analyzed and optimized with the proposed methods,yielding satisfactory design results.In this study,the necessity,effectiveness,and wide applicability of the presented method of thermal homology design and optimization for different structures and apertures of submillimeter-wave telescopes were demonstrated.The results show that not only are the developed theory and methods vital to the structural design and optimization of submillimeter-wave telescope antennas but they can also be applied to the design and optimization of radio telescope antenna structures of other wavebands.Our study enhances the theory and method of the antenna design for high-performance radio telescopes.