Research On MMIC Of Millimeter Wave Frequency Multiplier

With the continuous improvement of the working frequency of the system,millimeter-wave transceiver system has become a hot topic in recent years.It is also very important to obtain stable millimeter-wave source.Monolithic integrated circuit(MMIC)can simplify the circuit,improve the stability of the system and reduce the cost.In millimeter-wave transceiver system,it is very difficult to obtain high-frequency local oscillator signal directly.The generation of local oscillator signal is usually realized by low-frequency signal source and frequency doubling chain.Millimeter-wave frequency doubler is the key component of millimeter-wave system.In view of this,the main content of this paper is to develop two millimeter wave frequency doubling chains MMIC based on GaAs technology.The first nine-fold chain is mainly composed of W-band tripler,W-band power amplifier and G-band tripler.The second six-fold chain is composed of W-band doubler,W-band amplifier and G-band tripler.Firstly,this paper makes a research and reference on the design of MMIC of frequency multiplier at home and abroad,compares various common structures of frequency multiplier,and determines the scheme adopted in this design.For the first nine-fold chain,two triplers and a four-stage amplifier are used.According to the passive multiplier theory,using the nonlinearity of the diode and the topology of the reverse parallel diode pair,not only the problem of processing the bias circuit of the tripler is solved,but also the odd frequency multiplication can be realized effectively,and the fundamental and second harmonics can be effectively suppressed.For W-band power amplifier,according to the output power of W-band multiplier and the input power required by G-band multiplier,four-stage amplifier is used to select the appropriate DC bias point and the matching circuit topology to restrain the low-order harmonics again.Finally,the high-power output and high-harmonic suppression of MMIC are realized.Considering the overall circuit layout and transmission line loss,microstrip line is used as transmission line for W band multiplier and amplifier,and coplanar waveguide(GCPW)is used as transmission line for G band multiplier.The second is the six-fold chain,which uses a W-band active doubler and a G-band tripler plus a W-band two-stage driver amplifier.The layout of the whole six-fold chain is designed with coplanar waveguide as the transmission line.In this paper,135 nm GaAs process and 100 nm GaAs process are used.Some electromagnetic simulation softwares are used to simulate and optimize the passive devices such as transmission lines,capacitors and resistors.Then the schematic and layout simulation of the whole link are carried out.According to the simulation results of the final layout,for the nine-fold chain MMIC,the output power is greater than-5.5 dBm,and the total area of the chip is 3 mm*1 mm.For the six-fold chain MMIC,the output power is greater than-4.5 dBm,and the total area of the chip is 2.2 mm*0.6 mm.