Research On The Key Technologies Of Mixers Applied In RF T/R Modules On A Single Chip

Development of the technologies and design skills in microwave solid-statecircuits gives a strong sustain for microwave and millimeter wave being used inwireless communication area. Specially, development of the technology in siliconintegrated circuit makes not only the Microwave Monolithic Integrated Circuits(MMIC), but also the RF integrated System on a Chip operating in microwave andmillimeter wave band into reality. T/R module is the key technology in pashed arrayradar, which plays a decisive role in radar performance. Design of High integration andlow cost radar T/R module becomes a focus in recent years.Being an important block in T/R module, mixer has a critical effect on theperformance of the T/R module, whose linearity nature influences the linearity of theentire system. Modern active phased array radar system requires the mixers in itperform high gain and high linearity properties at the same time, making the design ofthe mixer a harder work.Under that background, the key point is how to design a mixer that performs highgain and high linearity. This thesis proposed a high gain and high linearity foldedmixer, which was designed by optimizing the traditional double balanced mixer onmany aspects. By adopting the Multiple gated transistors (MGTR)(or derivativesuperposition) method in the structure, the third-order input intercept point (IIP3) ofthe mixer increased efficiently as well as its convertion gain isn’t degraded. In order toimprove the performance of the mixer further, a LC tank is used in the LO stage andtwo current steering PMOS transistors in load stage. The interface at the three ports ofthe mixer is also designed in this thesis. A cascode active balun is used in the RF andLO ports respectively to convert single ended signal to a double ended one. At the IFoutput port, a active balun and buffer is used to convert double ended signal to a singleended one and increase the mixer with load capacity at the same time. The introductionof the active balun greatly improved the integration of the mixer. The design of thelayout is given at last.The Mixer is designed in TSMC0.35μm SiGe BiCMOS technology andsimulated by Cadence Spectre RF. Simulation results show that the mixer achieves12.97dB conversion gain,2.88dBm input1dB compress point,16.18dBm third-orderinput intercept point (IIP3) and17dB Noise Figure under2.5V power supply.