Research On Design Technology Of Millimeter Wave Monolithic Integrated Mixer

As the low-frequency communication frequency band becomes more and more crowded,the frequencies of microwave and below frequency bands have gradually been unable to meet the needs of modern electronic communication.The World Radiocommunication Conference(WRC)has made it clear that the communication frequency adopted by the next-generation ultra-wideband communication technology will extend to the millimeter wave band.The rapid development of gallium arsenide and monolithic technology has also continued to provide new hot spots for research on millimeter-wave integrated circuits.Among them,Radio-over-Fiber(RoF)uses optical millimeter wave receiving technology to integrate the huge bandwidth of optical fiber communication with millimeter wave ultra-high frequency communication technology,which can effectively solve the problem of ultra-wideband high-frequency communication technology.In the optical millimeter wave frequency band receiving technology,the mixer is the core to realize the frequency change,and its performance directly determines the quality of the entire RoF system.Therefore,in millimeter wave communications,it is extremely important to develop and design high-performance,high-quality monolithic integrated millimeter-wave frequency mixers.In this paper,a monolithic integrated fundamental wave image rejection mixer is designed based on the 0.15?m PHEMT GaAs process.In the overall circuit of the fundamental wave image rejection mixer,the local oscillator signal source of equal amplitude and phase is fed into the grid of a pair of PHEMT tubes through the Wilkinson power divider,and the received RF signal is equal in amplitude by the Lange coupler.The quadrature phase is fed into the drain port of the PHEMT tube,and finally the two-channel intermediate frequency signals with the phase quadrature are taken out from the drains of the upper and lower mixer tubes respectively.Co-simulation results show that the fundamental wave image rejection mixer has a radio frequency signal of 33?40GHz,the local oscillator power is 10dBm,the conversion loss is less than 11dB,and the image rejection is greater than 24dB,reaching the preset index.At the same time,considering that different millimeter wave signal receivers can provide different local oscillator source power capabilities.In order to reduce the receiver's high requirements for the stable millimeter wave signal of the same frequency band of the oscillator source,this paper uses the same process as above to design a monolithic integrated second harmonic image rejection mixer.In the harmonic image suppression mixer,the second harmonic of the local oscillator signal is mixed with the received radio frequency signal,which greatly reduces the difficulty and cost of the overall receiver.The harmonic mixer adopts the dual Marchand Balun structure to feed the local oscillator signals of equal amplitude and phase to the grids of a pair of PHEMT tubes,and then uses the Lange coupler to feed the RF signals of equal amplitude and quadrature phase to the corresponding PHEMT.The drain of the tube,and finally the quadrature output intermediate frequency signal is taken out from the drain ends of the upper and lower pairs of PHEMT tubes.The results of the joint simulation show that the second harmonic image rejection mixer has a radio frequency signal of 33-40GHz,the local oscillator power is 18dBm,the conversion loss is less than 18dB,and the image rejection is 17?32dB,which basically reaches the preset index.