The Research And Design Of CMOS Millimeter Wave Mixer

With the flourishing of wireless communication device, transceivers which play asthe front end of wireless communication instrument is developing for wider band, lesspower dissipation, higher integration in recent years.CMOS transceiver can beintegrated with baseband signal processor which occupy the dominant chip area in SOC,it also have a good performance in millimeter wave band with the development ofsilicon technology. As60GHz signal is attenuated heavely by atmosphere，Q-bandtransceiver is more suitable for long distance and high speed wireless communication.Maybe it can be used as the last one mile reply for future high speed wirelesscommunication. In this thesis, we design a45GHz mixer for Q-band receiver.Mixer transfer received RF signal to IF signal. Owing to conversion gain, activemixer can not only suppress the noise from IF circuit, but also can decrease the gain ofLNA for a certain receiver. Because received small signal can be amplified by LNA, it’scompressed by mixer easily，so the linearity of mixer always restricts the dynamic rangeof a receiver. The noise figure of mixer also has a great impact on receiver.This thesis reveals how to calculate the conversion gain, noise and linearity ofactive banlanced mixer. All the calculations is based on ideal circuit firstly，thenexpanded to the conditions with offset and parasitics. After these, this paper shows howto improve the performance of a certain parameter in mixer and what’s the effect it willbring in. The above analysis can be a simple but helpful tutorial for mixer design.At last, we design a mixer based on TSMC90nm CMOS process. To theknowledge of the author, this is the first time that current bleeding technique appears inQ band. In the design, we use a differential inductor rather than two single inductors.This can improve the conversion gain and noise figure of mixer. Simulation resultsshows that conversion gain is higher than4dB, DSB NF is better than10dB, IIP3is-2.2dBm and IIP2is43.2dBm with LO power of-3.6dBm. Beneifting from doublebalanced structure, the LO-to-RF and LO-to-IF isolatons are better than76dB and32dB.Simulation results verify the correctness of the previous theoretical analysis.