With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer ...With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz.The simulated results verify that the test circuit with stepped-impedance filter bias network has a larger bandwidth than that with the radial stub.A microstrip interdigital capacitor is used in the third test circuit to replace the DC block,however,which does not show its advantage during the test frequency band.Based on the simulated results,the stepped-impedance filter test circuit can be used to evaluate microwave power devices in the whole C band,namely from 4 to 8GHz.展开更多
AIGaN/GaN high electron mobility transistor （HEMT） structures were grown on 2 inch sapphire substrates by MOCVD, and 0.8-μm gate length devices were fabricated and measured. It is shown by resistance mapping that t...AIGaN/GaN high electron mobility transistor （HEMT） structures were grown on 2 inch sapphire substrates by MOCVD, and 0.8-μm gate length devices were fabricated and measured. It is shown by resistance mapping that the HEMT structures have an average sheet resistance of approximately 380 Ω/sq with a uniformity of more than 96%. The 1-mm gate width devices using the materials yielded a pulsed drain current of 784 mA/mm at Vgs=0.5 V and Vds=7 V with an extrinsic transconductance of 200 mS/mm. A 20-GHz unity current gain cutoff frequency （fT） and a 28-GHz maximum oscillation frequency （fmax） were obtained. The device with a 0.6-mm gate width yielded a total output power of 2.0 W/mm （power density of 3.33 W/mm） with 41% power added efficiency （PAE） at 4 GHz.展开更多
文摘With the principles of microwave circuits and semiconductor device physics,three kinds of microwave power device test circuits are designed and simulated,whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz.The simulated results verify that the test circuit with stepped-impedance filter bias network has a larger bandwidth than that with the radial stub.A microstrip interdigital capacitor is used in the third test circuit to replace the DC block,however,which does not show its advantage during the test frequency band.Based on the simulated results,the stepped-impedance filter test circuit can be used to evaluate microwave power devices in the whole C band,namely from 4 to 8GHz.
基金This work was supported by the Key Innovation Program of the Chinese Academy of Sci—ences，the National Natural Science Foundation of China(Grant No．60136020)the Special Funds for the Major State Basic Research Project(Grant No．G20000683 and 2002CB311903) the National High Technology R&D Program of China rGrant No．2002AA3053041．
文摘AIGaN/GaN high electron mobility transistor （HEMT） structures were grown on 2 inch sapphire substrates by MOCVD, and 0.8-μm gate length devices were fabricated and measured. It is shown by resistance mapping that the HEMT structures have an average sheet resistance of approximately 380 Ω/sq with a uniformity of more than 96%. The 1-mm gate width devices using the materials yielded a pulsed drain current of 784 mA/mm at Vgs=0.5 V and Vds=7 V with an extrinsic transconductance of 200 mS/mm. A 20-GHz unity current gain cutoff frequency （fT） and a 28-GHz maximum oscillation frequency （fmax） were obtained. The device with a 0.6-mm gate width yielded a total output power of 2.0 W/mm （power density of 3.33 W/mm） with 41% power added efficiency （PAE） at 4 GHz.
