Research On Multi-channel RF Transceivers And Oscillators For The Next Generation Mobile Communication Systems

Nowadays,with the development of video and games online,social software platform,mo-bile payment and so on,consumers put higher requirements to their wireless terminal devices,such as mobile phones,while telecommunications operators also place a high premium on the development of this industrialization.Therefore,in order to fulfill the current requirement and future development,the development direction of the future mobile communication should be"more efficient","more rapidly" and "more intelligent".In the face of the development of the future mobile communication,the design of active inte-grated antenna based on the distributed network utilizing radio on fiber technology is included in this paper,however,"high integration" and "high efficiency" are its advantages.What’s more,the research on microwave and mm Wave wide-band RF front-end for wireless mobile communication is proposed in the paper,it could support much wider channel bandwidth and the application of massive MIMO to realize a higher transmission speed.Several key technolo-gies and problems are solved in this paper,such as the wide-band multi-channel RF transceiver module with compact conformation and high performance,filter and diplexer with high selec-tivity performance,voltage controlled oscillator and frequency synthesizer with ultra-low phase noise.The RF transceivers and modules designed in this paper have been used in several wire-less communication systems for the next generation mobile communication successfully.For illustration of these designs and innovations,the dissertation is organized as follows:1)To fulfill the requirement of high integration,high performance and high efficiency for the future mobile communication systems,based on the National Science and Technology Ma-jor Project "Energy Efficient Active Integrated Antenna",the remote RF unit for the distributed network and radio on fiber technology is designed in this paper.In this 2.6 GHz TDD system,the RF transceiver could support up to 8 x 8 MIMO configuration and its channel bandwidth is up to 100 MHz.Moreover,the system has a compact conformation with high performance and high efficiency,and it could be used in the base station and connected to the active integrated antenna conveniently.In the measurement of the real scene in Tsinghua University and Pote-vio Institute of technology,the RF unit worked well with the active integrated antenna in the IMT-Advanced Network and sailed through the project acceptance successfully.2)To aim at the development trend of the future mobile communication systems,such as higher frequency and multi-channel,an X-Band dual-channel receiver and a Ku-Band multi-channel frequency converter module are designed in this paper.The X-Band dual-channel re-ceiver’s channel bandwidth is 800 MHz and the gain fluctuation is better than 2.1 dB.The noise figure is less than 1.8 dB,the maximum gain is larger than 90 dB with 60 dB controllable range.The input 1 dB compression point is better than-30 dBm.The Ku-Band frequency converter module could support up to 4 down-convert channels simultaneously,while other two channels could be used as transmit and receive calibration channels.The frequency converter module op-erates at 16-18 GHz with a 40 MHz RF bandwidth.The down-convert channels are consistent with respect to their gain performance which is better than 1 dB,the gain fluctuation is better than 0.8 dB,the interference suppression is better than 50 dB,the spurious power is smaller than-70 dBm.Meanwhile,the gain fluctuation of the transmitter is better than 1.5 dB and its spuri-ous is smaller than-52 dBc.The volume of this module is small and it achieves the purpose of miniaturization.3)The substrate integrated waveguide(SIW)has been proposed in the past decades,for its low loss,high power handling capacity and easy to be fabricated with other planar circuits,it has been widely applied in microwave and millimeter wave circuits.Therefore,based on the SIW technology,an X-Band oscillator is proposed based on a SIW dual-mode bandpass filter with circular cavity in this paper.Moreover,a voltage controlled oscillator is designed based on this configuration by introducing a phase-shifter into its feedback loop.As a frequency stabilization element in the feedback loop,the dual-mode SIW BPF is designed at the oscillation frequency.Due to the transmission zero near the upper passband of the filter,a large group delay peak at the upper passband edge can be achieved to improve the X-band oscillator’s phase noise performance significantly.Measured results show that,the phase noise of this proposed oscillator is-135.5 dBc/Hz at 1 MHz offset frequency with a figure of merit(FOM)of-206.2 dBc/Hz.What’s more,another part of the work in this paper focuses on the SIW dual-mode circular cavity,the coupling mechanism of the degenerate mode is analyzed.By placing a metalized perturbation via-hole near the center of the circular cavity,the coupling amount between two degenerate modes and the position of the transmission zero can be controlled.Then a pseudo-elliptical filter and a diplexer are designed at 28 GHz.The out-of-band rejection level of the developed filter and diplexer is good,it benefits from the transmission zero introduced by this structure.4)To satisfy the demand of mmWave high-speed communication,the paper also focuses on the design of frequency synthesizer with ultra-low phase noise performance based on the National Science and Technology Major Project.First of all,several configurations of the fre-quency synthesizer and how does the phase noise performance affect the system’s RF perfor-mance is analyzed.Then,two Ku-Band frequency synthesizers are designed based on digital phase lock configuration,measured results show that the phase noise are about-103 dBc/Hz and-123.6 dBc/Hz at 10 kHz and 1 MHz frequency offset,respectively.The module has been used in several wireless communication systems and its performance could meet the require-ment of these systems.To improve the phase noise performance of this frequency synthesizer,a new configuration is proposed by combining the digital phase lock and analog phase lock together,and a new frequency synthesizer module is designed on Ku-Band.The analog phase lock is realized by using a sampling phase detector to generate an X-Band LO signal,while the digital phase lock is designed to realize a low frequency VCO as IF signal,then the RF signal is achieved by using a mixer.At the center frequency,the measurement results show that the phase noise are about-112.2 dBc/Hz,-120.7 dBc/Hz,-117.1 dBc/Hz and-136.4 dBc/Hz at 1 kHz,10 kHz,100 kHz and 1 MHz frequency offset,respectively.The results show that this frequency synthesizer has a good phase noise performance which could be used in an mm Wave wireless mobile communication system.