Research On General Purpose Broadband Transceiver Channels

With the rapid development of electronic information technology,the demand for electronic information systems with better comprehensive performance is increasing.The integrated RF system overcomes the disadvantages of the simple superposition of traditional single-function systems such as complex structure,severe mutual interference and large volume,making it an ideal implementation form of electronic information systems.Therefore,the integrated RF system has important research significance.The integrated RF system relies on a shared hardware platform and uses software to rationally regulate the hardware so that it has multiple capabilities such as communication and radar.Based on this prospect,a miniaturized general-purpose transceiver channel with 300 MHz real-time bandwidth for 800MHz-8GHz operating frequency is researched and designed.Firstly,according to the conventional receiving and transmitting channel structures,analyzing and comparing their respective advantages and disadvantages,a superheterodyne design framework was determined.Aiming at the wideband characteristics of the channel,a two-stage mixing combined with a high-IF frequency conversion scheme is adopted to achieve good image rejection while facilitating miniaturization design.Secondly,according to the determined design scheme,aiming at the design targets,the frequency conversion chains and the local oscillators are designed.For frequency conversion chains,mixing module,amplification module and filtering module are designed respectively.In the mixing module,mixers with excellent performance are selected to ensure the good isolation and linearity performance;In the amplification module,the appropriate low-noise amplifier,power amplifier and gain blocks are selected to ensure the reasonable allocation of the chain gain;In the filtering module,a RF low-pass microstrip filter using radial line stubs is designed while an innovative method is used to realize the rapid design of substrate integrated waveguide band-pass filters with sharp respond from passband to stopband.For local oscillators,based on the phase-locked loop frequency synthesis technology,it is realized by selecting a suitable phase-locked loop circuit and designing the filtering and local oscillator drive amplification modules.The measured results show that the phase noise of the first local oscillator is better than-100 d Bc/Hz @10k Hz at the frequency of 13 GHz,and-97 d Bc/Hz@10k Hz at the frequency of 16.5GHz.The phase noise of the second local oscillator is better than-101 d Bc/Hz @10k Hz at the frequency of 11.3GHz.Finally,the test results of the broadband transceiver channel are given.For the receiving channel,with good linearity,the maximum gain is more than 44 d B;the output IF flatness is within 2.9d B;the image rejection can reach more than 65 d Bc;the EVM of 16 QAM modulation mode with 50 Msps code rate can reach 1.92%.For the transmitting channel,the maximum transmission gain can reach more than 31.5d B,within 7d B of broadband fluctuation;the output1 d B compression point is higher than 9.7d Bm with good linearity;the EVM of 16 QAM with50Msps code rate EVM can reach 2.67%.The test results show that the broadband transceiver channel has great performance and meets the design requirements.