The Development Of Miniaturized Multicarrier Aggregation 5G Receiving Front-end

With the rapidly explosive development in nearly 40 years,mobile communicating technology is gradually moving toward to higher peak rate and greater network capacity.Higher peak rate requires wider transceiver bandwidth,but it is difficult to have continuous large bandwidth in the actual carrier spectrum.Therefore,combining small segments of the spectrum resources to form a larger bandwidth and increasing the availability of spectrum resources is increasingly necessary.Based on above,this paper develops an RF receiving front-end system based on miniaturized multi-carrier aggregation which can be applied in 5G base stations.The receiving front-end system developed in this paper works in three frequency bands,they are: 2515MHz-2675 MHz,3400MHz-3600 MHz and 4800MHz-4900 MHz.These three frequency bands are the 5G commercial frequency bands that the Ministry of Industry and Information Technology(MIIT)officially distributed to the three major operators on December 10,2018.By analyzing the index of the system and the sub-indexes for each component,completed the core components: the three-band bandpass filter and the broadband low noise amplifier.Finally,through cascade testing and debugging,the requirements of RF front-end system indexes are ultimately achieved.The core component of this paper is the development of three-band bandpass filter and it achieves a structure which adapting to substrate integrated waveguide(SIW)loaded with complementary split ring resonators(CSRRs).The bandpass frequency selection characteristic of the filter is achieved by loading CSRRs.Besides that,CSRRs have simple structure,easy to design and process,and have excellent electromagnetic characteristics.The form of SIW can not only meet the miniaturization requirements of the filter,but also its structure takes into account the advantages of the microstrip line and the metal rectangular waveguide: higher quality factor Q,less radiation loss,small size,light weight,low cost,easy processing and integration,etc.Finally,The different bandpass filters are achieved by loading the same or different size of CSRRs in SIW.By cascading and mathing the different filters,the three-band bandpass filter will be accomplished.Its final size is 27mm*47mm,the passband interpolation loss is low and there are three transmission zeros outside the band.Next step is the designs of the broadband low noise amplifier,according to a range of design,such as,the amplifier chip selection,suitable static working point,bias circuit design,stability analysis,Schematic diagram and layout simulation,layout drawing and processing etc that which achieves a 2GHz-5GHz broadband low noise amplifier.its full-band noise figure is 2.0dB below,gains 20.3±0.3dB,and its final size is 20mm*14mm,meeting the needs of the system.Above all,this paper develops an 5G RF receiving front-end system based on multicarrier aggregation which has an excellent performance.According to the receiving frontend test method,conducting the technical indicators which the system required: the gain of the whole system is 18.5±1 dB,the total noise of the front-end system is less than 2.1dB,the compression point of the output 1dB is more than 18 dBm and the input and output standing waves are less than 2,and its final size is 47mm*52mm.Therefore,the design of the receiving front-end achieves the design requirements.