Research And Design Of GaAs-based Ka-band Digital Amplitude-phase MMICs

Monolithic Microwave Integrated Circuits(MMICs)are microwave circuits that integrate multiple functions on the same semiconductor substrate and can cover modules such as PA,LNA,phase shifters,or attenuators.In recent years,based on the widespread use of technologies such as 5G wireless communications and phased-array radar,the demand for high-frequency MMICs has increased significantly.The study of amplitude-phase MMICs has a great significance for space communications,electronic countermeasures,and other fields.This thesis provides an overview of domestic and foreign Ka amplitude-phase MMIC of advanced scientific research and application of the results,it presented pieces of the structure and working principle of phase control MMIC.The design of the amplitude-phase control chip based on 0.15?m GaAs pHEMT process and the key modules analyzed in depth:digital driver control circuit,digital phase shifter,and digital attenuator.In this treatise,the input interface circuitry and TTL voltage generating circuit is improved to effectively ensure that the velocity control while reducing the power supply ripple,in addition,a power-on reset circuit has been added to effectively reset the initial state at power-on.Besides,an Analog to Digital Converter(ADC)is introduced in the driver control section to enable analog signal control of the RF signal to extend the application scenario.The digital phase shifter and digital attenuator are studied in combination with the overall system specifications of the pseudo-matched GaAs process and T/R components,the all pass and high-low pass topologies are chosen and the overall structure is finalized with adjustments based on the VSWR.With the above research,this thesis has completed an 8-bit serial-to-parallel converter,a 3-bit Flash ADC,a Ka-band 5-bit digital phase shifter,and a 3-bit digital attenuator based on the 0.15?m GaAs pHEMT process.The test results of digital control show that 8-bit serial-to-parallel converter circuit designed can be stabilized at frequency of 5MHz power up and reset,and work effectively at a frequency of 15MHz;the 3-bit ADC can perform basic AD conversion functions.The post-imitation of RF circuits show that the 5-bit digital PS's main specifications are as follows:VSWR?1.6,phase shift accuracy?5RMS° and a noise factor?8.5dB in the bandwidth of 29-33GHz,the 3-bit digital attenuator:attenuation step?1dB,attenuation accuracy?0.8dB.