We investigated the design method of an infrared (IR)/microwave (MW) micromirror array type of beam combiner. The size of micromirror is in microscopic levels and comparable to MW wavelengths, so that the MW will not react in these dimensions, whereas the much shorter optical wavelengths will be reflected by them. Hence, the MW multilayered substrate was simplified and designed using transmission line theory. The beam combiner used an IR wavefront-division imaging technique to reflect the IR radiation image to the unit under test (UUT)’s pupil in a parallel light path. In addition, the boresight error detected by phase monopulse radar was analyzed using a moment-of method (MoM) and multilevel fast multipole method (MLFMM) acceleration technique. The boresight error introduced by the finite size of the beam combiner was less than 1°. Finally, in order to verify the wavefront-division imaging technique, a prototype of a micromirror array was fabricated, and IR images were tested. The IR images obtained by the thermal imager verified the correctness of the wavefront-division imaging technique.
© 2013 Optical Society of America
Original Manuscript: April 12, 2013
Revised Manuscript: June 13, 2013
Manuscript Accepted: July 1, 2013
Published: July 24, 2013
Yi Tian, Lijun Lv, Liwei Jiang, Xin Wang, Yanhong Li, Haiming Yu, Xiaochen Feng, Qi Li, Li Zhang, and Zhuo Li, "Infrared/microwave (IR/MW) micromirror array beam combiner design and analysis," Appl. Opt. 52, 5411-5419 (2013)