We report the demonstration of a monolithic phase shifter employing Bi_(1.5)Zn_(1.0)Nb_(1.5)O_(7)/Ba_(0.5)Sr_(0.5)TiO_(3)(BST)thin films on sapphire substrates.The BST and BZN thin films are successively deposited by ...We report the demonstration of a monolithic phase shifter employing Bi_(1.5)Zn_(1.0)Nb_(1.5)O_(7)/Ba_(0.5)Sr_(0.5)TiO_(3)(BST)thin films on sapphire substrates.The BST and BZN thin films are successively deposited by radio-frequency magnetron sputtering.A distributed phase shifter with a coplanar-waveguide transmission line periodically loaded with the BZN/BST capacitors is fabricated.The return loss of the circuit is better than-13 dB from 1 to 12 GHz,and it provides 65°phase shift with an insertion loss of-4 dB at 12 GHz.The results show that BZN/BST thin films are promising candidate dielectrics for rf/microwave tunable applications.展开更多
Tunable and switchable Ba 0.5 Sr 0.5 TiO 3 film bulk acoustic resonators（FBARs） based on SiO 2 /Mo Bragg reflectors are explored,which can withstand high temperature for the deposition of Ba x Sr 1 x TiO 3（BST） fi...Tunable and switchable Ba 0.5 Sr 0.5 TiO 3 film bulk acoustic resonators（FBARs） based on SiO 2 /Mo Bragg reflectors are explored,which can withstand high temperature for the deposition of Ba x Sr 1 x TiO 3（BST） films at 800 C.The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect.The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing,while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias（ 45 V） while downwards at higher dc bias.The calculated relative tunability of shifts at series resonance frequency is around 2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias,which can be comparable to AlN FBARs.This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum（Mo） as the high acoustic impedance layer in a Bragg reflector,which not only provides excellent acoustic isolation from the substrate,but also improves the crystallinity of BST films withstanding higher deposition temperature.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60871049 and 50972024.
文摘We report the demonstration of a monolithic phase shifter employing Bi_(1.5)Zn_(1.0)Nb_(1.5)O_(7)/Ba_(0.5)Sr_(0.5)TiO_(3)(BST)thin films on sapphire substrates.The BST and BZN thin films are successively deposited by radio-frequency magnetron sputtering.A distributed phase shifter with a coplanar-waveguide transmission line periodically loaded with the BZN/BST capacitors is fabricated.The return loss of the circuit is better than-13 dB from 1 to 12 GHz,and it provides 65°phase shift with an insertion loss of-4 dB at 12 GHz.The results show that BZN/BST thin films are promising candidate dielectrics for rf/microwave tunable applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60871049 and 50972024)
文摘Tunable and switchable Ba 0.5 Sr 0.5 TiO 3 film bulk acoustic resonators（FBARs） based on SiO 2 /Mo Bragg reflectors are explored,which can withstand high temperature for the deposition of Ba x Sr 1 x TiO 3（BST） films at 800 C.The dc bias-dependent resonance may be attributed to the piezoelectricity of the BST film induced by an electrostrictive effect.The series resonant frequency is strongly dc bias-dependent and shifts downwards with dc bias increasing,while the parallel resonant frequency is only weakly dc bias-dependent and slightly shifts upwards at low dc bias（ 45 V） while downwards at higher dc bias.The calculated relative tunability of shifts at series resonance frequency is around 2.3% and the electromechanical coupling coefficient is up to approximately 8.09% at 60-V dc bias,which can be comparable to AlN FBARs.This suggests that a high-quality tunable BST FBAR device can be achieved through the use of molybdenum（Mo） as the high acoustic impedance layer in a Bragg reflector,which not only provides excellent acoustic isolation from the substrate,but also improves the crystallinity of BST films withstanding higher deposition temperature.
