Research On Key Techniques Of Millimeter-Wave Frequency Quadrupler Chain

In recent years,with the rapid development of wireless communication technology,millimeter-wave(MMW)frequency sources have been widely used in remote sensing,medical treatment,imaging and detection systems.MMW frequency sources are the most critical module in the radio frequency(RF)front end of wireless transmitters.So the research on MMW frequency sources are always under the spotlight.Throughout the development of MMW frequency sources,the research mainly focuses on how to improve the output power,bandwidth and spectral purity.However,due to the limitation of the integrated circuit technology,MMW signals generated directly by oscillators suffer from low output power,narrow bandwidth and poor stability,which limits the overall performance of MMW system.Therefore,a multiplier chain cascaded with a low-frequency oscillator is employed to generate a high-frequency stable signal.In the thesis,the key design techniques of MMW frequency multiplier are deeply studied.A wideband MMW frequency quadrupler chain with high conversion gain,high output power and high harmonic suppression is proposed,providing a guideline for the implementation of high performance MMW frequency sources.The main work and innovation points of this thesis are as follows:(1)To solve the problem that the amplitude and phase between the outputs of conventional active baluns become mismatched at high frequency,a magnitude and phase indirect correction technique is proposed.This technique can correct gain and phase error simultaneously.Based on this technique,a novel millimeter-wave active balun structure for frequency multiplier chain is proposed.The 3-d B bandwidth of balun is 105-128 GHz.The outputs have gain error(GE)lower than 0.4 d B and phase error(PE)lower than 5°.(2)A modified gm-boosted push-push balanced frequency multiplier structure is studied and designed.By changing the driving mode of differential inputs,the swing of the input signal is increased,and then the conversion gain is increased.At the same time,harmonic suppressions of the fundamental and the odd are improved.The conversion gain is higher than-4 d B.Harmonic suppressions of the fundamental and the odd are better than 30 d Bc.(3)This thesis presents a 230 GHz frequency quadrupler chain.Based on the above two aspects,a frequency quadrupler chain combining a single-ended frequency doubler and a balanced frequency doubler is proposed.An active balun is employed in the frequency multiplier chain,thus a broadband MMW frequency quadrupler chain with high conversion gain,high output power and high suppression is designed.The chain reaches a 3-d B bandwidth of 19.7%(210-256 GHz).It achieves-0.55 d B peak conversion gain and-0.5 d Bm saturated output power.All harmonic suppressions are over 20 d Bc.