Research Of The Low Noise Amplifier In Millimeter-wave Radio Frequency Front-end

With wireless communication developing,the contradiction between the limited spectrum resources and high data rate constantly intensifies.In order to resolve this problem,the development of higher frequency bands and even millimeter waves has become an inevitable demand.The millimeter wave corresponds to a frequency range of30³00 GHz.This bandwidth is equivalent to 10 times the total bandwidth of the DC to centimeter waves.Besides,the millimeter wave has many excellent characteristics,making the millimeter wave a research hotspot in recent years.In 2009,the International Institute of Electrical and Electronics Engineers issued a protocol standard for the 60GHz millimeter wave band,announcing the opening of 57.2⁶5.8GHz for high-speed wireless Local Area Networks,which is quite suitable for short-distance communication.At present,the 60GHz unlicensed band is open to all major countries and regions in the world,which promotes research applications in the 60 GHz band.The RF receiver is a bridge between the electromagnetic wave signal and the analog circuit.As the first stage of the RF receiver,the gain and noise figure performance of the low noise amplifier plays a decisive role in the sensitivity of the whole system.The performance parameters such as reflection coefficient and linearity also affect the performance of the whole circuit.The design of low noise amplifiers is very difficult.Especially in the millimeter wave circuit,the parasitic effect of components is very significant,and the operating frequency is approaching the limit of the transistor.This all makes the design difficulty of the millimeter wave low noise amplifier further increased.After considering various constraints and requirements,this paper designs a low power and high gain 60 GHz low noise amplifier.At present,there are many structures for improving the gain of a low noise amplifier,such as a capacitive cross-coupling neutralization structure,a common-gate inductive feedback structure,and the like.However,these structures generally have problems such as complicated structure,limited gain improvement,or high power consumption.In order to meet the requirements of low power consumption and high gain at the same time,this paper proposes a two-stage low noise amplifier,in which the first stage is a regulated cascode structure and the second stage is a traditional cascode structure.In the design process,there are two main difficulties.The first difficulty is that the operating frequency of the transistor is approaching the limit,which causes the gain and noise performance of the transistor to deteriorate.The second difficulty is that the model of the passive device has changed.The length of the transmission line cannot be ignored relative to the signal wavelength.The voltage and current at each point on the transmission line will change with the spatial position.The transmission line usually shows the performance of the inductor.The inductor model of PDK has also become less precise in the 60 GHz band.Electromagnetic field modeling of inductors and transmission lines has become necessary.In order to meet the requirements of low power consumption and high gain at the same time,this paper proposes a two-stage low noise amplifier,in which the first stage is a regulated cascode structure and the second stage is a traditional cascode structure.Finally,the simulated results show that the proposed LNA achieves a power gain of16.5dB.The 3dB bandwidth is 8GHz from 57GHz to 65GHz.The noise figure is 5.8dB at 60.5GHz and lower than 6.1dB in the whole band.The input reflection coefficient and the output reflection coefficient are both less than-10dB.The input 3^rd intercept point IIP3 is-8.5dBm.The stable factor K is greater than 1 and the power consumption is19.9mW with a 1.1V supply.