The Design Of Wireless RF Front-end Receiver Circuit

Recently, with the rapid development of communication technologies, radio frequency wireless communications technology is playing an important role. RF circuit manufacture has a vast market, which has become a hot field of wireless communications. Based on above, this article is conducted in-depth study in the front-end RF wireless receiver circuit.Firstly, RF antenna and filter design were introduced in this article. In the beginning, the detailed design process of antenna diameter circular polarization is given, using simulation software-Ensemble 2.4GHz micro strip antenna on the simulation. Basing on the design of a simulation of 2×2 array of patch element in ensuring optimum performance, we reached a relatively satisfactory result. Filter design was based on the first-order plural band-pass filter topology structure, using a RC active structure. After simulating, the result is that the plural filter centre frequency is 20KHz and the gain is 13dB, not only reducing the base-band amplifier burden of the DC Resistance (DCR) suffix, but also suppressing the interference to -20KHz on the mirror -20KHz. To the desired signal, mirror-frequency signal inhibition is -33dB, to meet the general image reject requests for low-IF receiver front-end RF circuits.Then, the low noise amplifier and the mixer were discussed in the article. In the design of low-noise amplifier (LNA), we optimized the general LNA circuit at four aspects, which were noise, input impedance matching, gain and degree of linearity. And we used the optimization of the optimum design methods on noise and linearity to design the 2.4GHz low-noise CMOS amplifiers, in 0.25μm CMOS technology. The result of the circuit simulation is that the frequency is 2.4GHz, the bias voltage is 3.3V, the LNA the noise figure (NF) is 1.97dB, to meet the design requirements and give the low noise amplifier design territory.In this paper, the double-balanced Gilbert mixer structure is used for the mixer design, by optimizing the traditional Gilbert mixer at linearity and load. The load was formed by active PMOS load and parallel RC network. Using the ADS simulation software to simulate, we got that the conversion gain is -11.5dB, the third-order distortion is 2.43dBm, the 1dB gain compression point is -5.656dBm, the single sideband noise figure is 10.56dB. Through the simulation results contrast, we can see the improved circuit performance has been significantly improved.Finally, a 2.4G RF front-end complete circuit is designed. After simulating, we analyse the band selectivity, the receiver channel selectivity, the gain, the input standing wave and the circuit stability performance of the RF front-end circuit, to receive further illustrates the design of this paper has a certain practical value.