| In June 2019,the Ministry of Industry and Telecommunications issued four 5G licenses,which were acquired by the three giants of operators and China Radio and Television,marking China’s formal entry into the 5G business year.In the following three years,the communications industry has made great progress,with some new products,such as 5G mobile phones,Wi Fi6 and so on,coming out.With the continuous update of communication products,the capacity of corresponding products has been improved,and the requirements for the key unit of RF front-end are also increasing,especially the part of low noise amplifier.Wideband is required,not only for high performance,but also for little power consumption and smaller area.Based on market demand,a low noise amplifier in 5.15-5.85 GHz and a 4-6GHz wideband dual mode low noise amplifier are designed.Through the design and testing of the chip,the result has reached the expected performance.The low noise amplifier of 5.15-5.85 GHz,using the Ga As p HEMT process of 0.25 μm,is designed based on the classical cascode structure,which ensures that the circuit has good boost performance,good linearity,lower noise and so on.By using LC topology as input matching network,a narrow-band input is constructed,which ensures the interference signal is filtered out and the input loss and noise factor of the signal as smaller as possible.The maximum output-signal power is guaranteed by the output matching of LC structure.Optimal design of the schematic and layout and subsequent chip-to-chip testing are carried out.The test results verify the good performance of the chip in the working band.The gain of about15 d B and the noise figure of about 1.75-1.95 d B,achieved in the working band,and the input power gain compression value of P1 d B is-3 d Bm.Another 4-6 GHz wide band low noise amplifier is based on the previous topology,used the Ga As p HEMT process of 0.25 μm to achieves new functionality by expanding bandwidth and adding Bypass mode.In order to achieve a wider bandwidth,there are two main aspects.On the one hand,in terms of input matching,a broadband band-pass filter is constructed using passive devices such as capacitance and inductance.Because the inductance introduces more power loss and noise than the capacitance in high frequency,the minimum inductance value and the higher Q value of the inductance are selected when designing the inductance.On the other hand,the design of the output matching network.In order to get a large gain and bandwidth for the output signal,the output matching network uses parallel peak technology.The Bypass mode protection circuit is increased,avoid from power leakage caused by switch delay,and the entry of other larger power signals when the low noise amplifier is not working,damages the low noise amplifier.At the same time,in order to save the layout area,some switch structures are involved in input matching through logic control when the amplification circuit works.The experimental results show that the signal gain of 12 d B is achieved in the4-6 GHz,the gain flatness is ±0.8 d B,and the noise factor is about 1.5 d B.The power gain compression value of the input P1 d B is-2 d Bm.The insertion loss in Bypass mode is about-12 d B,which provides better isolation protection.The overall performance of the chip satisfy the expected performance. |
