Research On Key Integrated Circuits Of Millimeter-wave Front-end

In this work,several key components of the typical millimeter-wave front-end,including switches and multipliers as well as low noise amplifiers,power amplifiers,have been analyzed and designed,mainly for the mm-wave imaging radar application.Thanks to the state-of-the-art GaAs mHEMT technology and the precise EM modelling and simulation,all of the MMICs developed in this work have exhibited good performance.To build a solid foundation for the circuit design,accurate EM models of the various passive components,such as capacitors and via holes,have been developed at the beginning.Using the full-wave EM simulator,the models have the characteristics of Scatter Parameters being similar with the Process Design Kit at the lower frequency and more consistent with the measurement results at millimeter-wave band.Moreover,accurate GSG pad models have been explored using all kinds of EDA tools and various simulation mechanism.As the control components of most mm-wave transceivers,SPDT switches have always been critical in the system design.Using the travelling-wave concept,a broadband E-band SPDT switch MMIC has been proposed in this work,with excellent insertion loss and isolation performance.Unfortunately,due to the extremely small periphery of the passive mHEMT devices,the MMIC is not able to handle high transmission power.Besides,a PIN diode based SPDT module has also been presented in this thesis.As a result of the good characteristic of power capacity of the PIN diode,the module exhibits good power performance.However,the measurement results do not agree well with the simulation results,the solution to improve the accuracy of the PIN diode model has been presented,for the subsequent work.To implement a stable signal source in a mm-wave front-end,frequency multiplication in combination with high quality lower frequency synthesizers is widely recognized as a better approach to generate accurate and stable signals.In this work,a W band frequency multiplier-by-six has been proposed using GaAs mHEMT technology.Precise EM models have been adopted in the design and due to the active and balanced configuration of the circuit,impressive conversion gain has been realized.The LNA is a key component of any receiver system.It is placed at the front end of a receiving system to improve NF of the total system as well as providing the initial boosting of signal.In this work,utilizing the GaAs mHEMT technology,two W-band LNA have been proposed and exhibit good performance over the entire W band.The first LNA is implemented in a whole micro-strip environment and the second one is implemented in GCPW environment.Details of the design and EM simulation of the circuits have been discussed and comparison between these two LNAs has also been presented.Especially,different methods of carrying out the whole-chip EM simulation,including using the EM models of the HEMT devices which are innovatively developed in this work,are discussed.It is the output power of the transmitter that's in charge of the operating distance and ability of antiinterference at a millimeter-wave system.Power amplifier is absolutely essential at a millimeter-wave front-end.In this thesis,a W-band power amplifier utilizing 0.13 um GaAs mHEMT technology has been proposed,the simulation results demonstrated that this MMIC exhibits good performance in terms of power transmission.