| The rapid development of semiconductor device technology has attracted extensive attention to the development and research of the terahertz band(0.1THz-10THz).For a long time,the terahertz frequency has been considered as a "blank" area in the electromagnetic spectrum,and its large bandwidth enables the terahertz communication system to work at an ultra-high rate,so it is also considered to be an important part of the new generation of wireless communication technology.This paper mainly designs and conducts experimental research on functional chips such as dynamic switching chips,active frequency multiplier chips and chip packaging in the terahertz system.The main work completed includes the following aspects:(1)In view of the low operating frequency of the current switch chip,the insertion loss and isolation are difficult to balance,four 220 GHz switching dynamic chips are designed using the 90 nm InP-based HEMT process.Three of them use a single-segment microstrip and cascaded HEMTs topology,and the fourth innovatively uses the combination of single-die HEMT and terahertz microstructure(meta-chip).Through strict tape-out process and on-chip testing,the experiment shows that the maximum switching ratio of the two-die cascaded chip can reach 35 Db,achieving a large switch-ratio characteristic;the isolation of the three-die cascade structure is greater than 20 d B,the insertion loss is less than 5d B,the bandwidth can reach 13 GHz,and the modulation rate can reach 13 GHz.Modulation rate up to 1Gbps,which realizes the function of wideband and high-speed dynamic switching.Compared with the ordinary chip;the single-die switch chip combined with the microstructure increases the switch ratio by 2d B compared with the ordinary chip,which reflects the advantages of the meta-chip.(2)Aiming at the current situation that there is less work on active frequency doubling chips and low frequency doubling efficiency,the 140 GHz frequency doubling and 220 GHz frequency doubling chips are constructed using the InP-based HEMT process.The simulation and optimization of the gate and drain DC bias circuits,the input fundamental wave and the output harmonic matching circuit in the active frequency multiplier chip are carried out.The experimental test of the double frequency of 140 GHz has been completed.The experimental measurement shows that the maximum frequency conversion gain is 0.35 d B,and it has a 3d B bandwidth of nearly 13 GHz.The simulation and experimental results are basically the same,which verifies the reliability of the design method.(3)For the trend of terahertz systems moving towards modularization,this paper designs a package module for a single-function chip.The transition between the chip and the waveguide is realized by using the E-face probe and the gold wire bonding back-toback transition structure.The fixed loss of the cavity is 1-2d B.The simulation optimizes the flip-chip transition structure,and completes the low-frequency Rogers version and the pcb design and chip packaging of the DC power supply board.The measured result of the back-to-back structure of the 220 GHz InP-based low-noise amplifier package chip is that the insertion loss is lower than 2.5d B around 20 GHz bandwidth;the test result of the60 GHz IQ mixing package chip is that the insertion loss is lower than 3d B around 10 GHz bandwidth,and The combined conversion loss is between 11 d B and 12 d B,which can be used in terahertz communication systems.The terahertz dynamic switch chip and terahertz active frequency multiplier chip designed in this paper provide a complete idea and a new method for the design of singlefunction chips,and the packaging technology provides a strong guarantee for promoting the modularization of terahertz chips. |
PDF Full Text Request