| According to Edholm's law,the data rates of wireless communication systems may reach 10 Gbps or higher in 2020.The millimeter-wave(mmW)wireless communication systems offer a choice for the high data rate and broad communication.Mixers are the key components of transceivers.Especially when the commercial low noise amplifiers or power amplifiers for above 100 GHz applications are extremely expensive or difficult to implement,mixers may become the first stage of receivers or the last stage of transmitters.The performances of wireless communication systems will be determined by mixers.There are numerous kinds of methords to improve the conversion gain,3dB bandwidth and so on.With it,many other problems appear,such as the areas increased.Thus,in this dissertation,some novel topologies are developed to reduce the chip size of monolithic millimeter wave integrated circuits(MMICs).The main contributions are listed as follows:1)In order to improve the accuracy of the on-chip passive component model used in mmW field,the modeling methods are studied as followed knowing the parasitic effects and loss mechanism.As the development of process,the EM models of on-chip passive devices,such as transmission line,are modeled utilizing 3D EM simulation tools HFSS or Momtenum based on their own characteristics.The simulated and measured results indicate that:up to 220 GHz,the models could predict the characteristics of on-chip passive devices.2)To reduce the fabrication cost and broaden the bandwidth,two monolithic methods using lumped-elements are proposed.Meanwhile,the spiral-type Marchand balun is also introduced to.By adjusting the output imbalance of the coupler and balun,the bandwidth is broadened.The APDP-basded Sub-harmonic mixer(SHM)with modified quasi-lumped components is manufactured.The proposed mixer performed a measured conversion gain of-13.5±1.5 dB and the 3dB bandwidth is 20 GHz.Experimental results show that the quasi-lumped topology can be used to trim down the fabrication cost and without sacrificing the performance of conversion gain.Among the reported compound works,the area of the circuit is the smallest.3)To verify the design approaches of D-band monolithic mixers,the quarter-wavelength open stub and the half-wavelength sthorted-stub are used to absorb the RF and LO signals,a conversional structure D band SHM is manufactured.Experimental results show that the conversion gain locates in-20.4 dB?-14.1 dB.The measured data is in reasonable agreement with the simulation within the RF bandwidth from 110 GHz to 145 GHz.Meanwhile,in comparison to the cited works,we can note that the present mixer achieves outstanding FOMs.4)To solve the problem of reducing the chip area of the lumped elements unapplicable in mmW,a modified asymmetric three-conductor coupler is proposed to cut down the area cost.The chip size is only 70%of the conversional structure.The design mixer has a measured maximum conversion gain of-13.9 dB and the 3dB bandwidth is 32 GHz.Without sacrificing the performance of conversion gain,the circuit is the smallest D-band SHM among the reported works.5)By adjusting the LO power and the gate voltage,matching networks were designed for both local oscillator(LO)and radio frequency(RF)signals.A CPW D-band passive mixer operating in dual resistive/drain modes has been implemented.For drain mode,a measured maximum conversion gain was-4.4 dB.In case of resistive mode,the circuit performed a best conversion gain of-8.0 dB.Taking into account the conversion gain,3dB bandwidth and LO power consumption,the mixers have outstanding FOMs compared with the reported works.Based on 70 nm GaAs mHEMT and lum InP DHBT processes,the thesis analyzes knowing the parasitic effects and loss mechanism in detail,establishes the EM models and designs three different types of V-band SHMs,two types of D-band SHMs and a D-band dual-mode fundamental mixer.The innovative works in the research of the MMIC mixer have certain academic and application values for the passive devices modeling and MMIC design. |
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