Research And Design Of GaAs UWB Mixer

Mixer is a key component in communication systems and plays an important role in various fields such as radar,satellite,remote sensing,measurement,and electronic countermeasures.With the rapid development of communication and electronic systems towards broadband,miniaturization and integration,monolithic microwave integrated broadband mixer circuits have become one of the research hotspots due to their many advantages such as wide bandwidth,low loss,and easy integration.This thesis introduces the research background,research significance and domestic and foreign research status of the mixer in turn,and analyzes the working principles,advantages and disadvantages of mixers and baluns in different types and structures.A broadband passive doublebalanced mixer was designed in using the WIN 0.15μm Ga As PHEMT process and an ultra-wideband passive double-balanced mixer was designed in using the Guo Ji Nan Fang 0.15μm Ga As PHEMT process.The sample of mixers are measured.The operating frequency of the broadband passive double-balanced mixer is 14-22 GHz,and it adopts the traditional spiral Marchand balun structure.The measurement results show that there is a large gap between the test and simulation results of frequency conversion loss and VSWR-IF.After confirming that there are no errors in the simulation software settings,measurement scheme and measurement operation process,the reason may be that the PHEMT device model is not accurate.The wideband passive double-balanced mixer failed to meet expectations.The operating frequency of the UWB passive double-balanced mixer is 8-26 GHz.Because the traditional spiral Marchand balun cannot meet the wide bandwidth and good port matching characteristics of the wideband mixer at the same time,this thesis solves this problem by adding a compensation capacitor at the end of the balun.The measurement results show that the Conversion Loss is less than 8.5d B,RF-IF isolation is greater than 17 d B,RF port VSWR is less than2.4,the VSWR of LO and IF ports are both less than 2.The difference between measurement results and simulation results is small.The ultra-wideband passive double-balanced mixer has achieved expectations,and has certain advantages compared with the same type of mixer at home and abroad.