Research And Implementation Of RF Front-end For Ka Band Wideband FDD-TDD Digital Microwave Communication System

As one of the resources, the electromagnetic spectrum is further explored andstudied by human in recent years, and there is no doubt that the entire electromagneticspectrum will be occupied and be made the best use, so as to serve human society byusing these rich and rare spectrum resources. Millimeter wave shows great advantagesin bandwidth, radiation, propagation, reception, systems integration and applications. Inthe1970s, the International Telecommunication Union (ITU) World Radio Conferencehas divided and allocated the30GHz~70GHz millimeter wave band which is using forcommunication services. With the acceleration of the informatization process of society,development and utilization of the electromagnetic spectrum is becoming increasinglyurgent and necessary, millimeter-wave even terahertz has become an important researcharea in international community, greatly accelerating the development of millimeterwave communication technology.Combined with the development of millimeter-wave integrated circuits andwireless communication data services in recent years, this article presents a front-enddesign and fabrication both for FDD and TDD channelized digital microwavecommunication systems at the desired frequency of32GHz and38GHz band. Thesystem uses double conversion superheterodyne receiver and the double conversiontransmitter program and so the millimeter-wave front-end includes transmitting andreceiving module. The transmitting module up-converts the IF signals to Ka band andthe receiving module down-converts Ka band signals to L-band, and high isolation isrequired between the two modules. The front-end features the multiband millimeterwave transceiver and the frequency multiplication chains that meet the specifications forKa-band communication channel selection, at the same time multiplication chainsdemand high spurious suppression and low phase noise. The article detailed study thefrequency arrangements for this system, system design and simulation, keymillimeter-wave components design and selection, cavity design, testing power design,etc.Tested by experiment, the dynamic range of the communication systems T/R link is 30dB respectively, and the integrated NF, IF bandwidth, sensitivity of the receiver isbelow6dB,22MHz, below-85dBm@SNR10dB respectively. The transmit power couldbe up to15.4dBm and the ACPR is40dBc, achieving the200m-5km range of wirelesscommunication. This front-end could be used in LMDS cellular communication systemas well as other wideband digital microwave communication system with adaptivemodulation scheme, such as QPSK,16QAM,32QAM,64QAM, etc.