Low Loss And Large Size Microwave Single Crystal Film Epitaxy And Microwave Devices Integration Technology

In recent years, the rapidly development of wireless comminication and mobile communication has brought lots of convenience to human beings. The improvement of rader technology has been applied in field of military and civilian. Yttrium garmet ferrite material pocessed low magnetic loss, high applied frequency, and it has been uesd in many devices in radio frequency and microwave field. In addition, single crystal thin film of nano-thickness yttrium garmet ferrite has drawn more attention at spin wave devices application, and the nano-thickness thin films parpered by LPE method have great science application value. Ferrite circulator is the most important devices in wireless comminication and radio field. In the present work, based on LPE technology and CPW technology and strip line magnetism, the miniaturization and high performance of ferrite circulator were invesigated.About materials, the effects of La ion substitution and annealing technology of Yttrium garment thin films by magnetron sputtering method were investigated. The results showed that the 10 min anealing time could not make YIG films to crystallization, and showed that 800℃ was the best crystallization temperature for YIG film. Using conventional annealing process, 800℃ annealing temperature for 2h and cooling in air, the good results were obtained, and the different La substitution content affected different grian growth, and Y2.97La0.03Fe5O12 films had excellent grains and low FMR. Using LPE method, the influences of substrate rotation rate and GGG substrate on YIG films were investigated in present work, and we explained that both different GGG substrate led to different properties films to research the optimum process. The results showed that growth rate increased with rotation speed to a maximum value.(111) and(100) crystal orientations had obvious effects on magnetic properties of films, different crystal orientation had different VSM loops.About devices, more than 20 μm thickness YIG films were perpared by LPE technology. Based on strip line circulator, three dimensional electromagnetic field sumulation design and parameter optimization were done by HFSS software. The metal signal plane was perpared by photolithographic process and magnetron sputtering method, and Xband film circulator was designed based on CPW technology. The test results showed that the center frequency of circulator was 11.5 GHz, the bandwidth was 300 MHz at 3 dB, and insert loss more than-4 dB, and return loss was less than-20 d B.