Design Of An On Chip Radio Frequency Filter

With the rapid development of wireless communication technology and the continuous evolution of 5G communication,the trend of miniaturization,high integration and high performance of terminal has become increasingly obvious.RF(Radio Frequency)filter which plays a role of frequency seletction is an essential component in the RF front-end system and its performance directly determines the quality of the system.As the operating frequency enters the field of millimeterwave,it has exceeded the operating frequency range of acoustic wave filter,it is urgent to find a highly integrated millimeter wave filter to meet the demand of wireless communication system.On account of large operating frequency range,ease of integration,low cost and other characteristics,Semiconductor on chip filter as one of the alternative technologies of acoustic wave filter,and its miniaturization and performance is the research emphasis.So,study on well-performing and highly integrated RF on chip filter is a key work for promoting the development of the next generation wireless communication system.Based on the traditional transmission line theory,this thesis analyzes the equivalent circuit of the pure left-handed transmission line and its unique electromagnetic phenomena.On this basis,the electromagnetic propagation characteristics of the Composite Right/Left-Handed(CRLH)transmission line and its application in RF and microwave passive devices are analyzed according to its equivalent circuit.Based on the structure of the CRLH transmission line,the advantages of the CRLH structure in RF filter design are demonstrated by the printed circuit board(PCB)process and semiconductor Ga As process respectively.The main work and innovation of this thesis include the following aspects:1?Based on the traditional rectangular interdigital capacitor,an improved zigzag interdigital capacitor is proposed.By analyzing and improving the calculation formula of interdigital capacitor,it is shown that the improved zigzag interdigital capacitor has a larger capacitance with the same size.Its application in CRLH structure can reduces the resonant frequency and decreases the size of filter.2?Based on the improved zigzag interditital capacitor,this thesis designed a PCB bandpass filter which applied to the Sub-6G application,the proposed filter combined with CRLH structure and Substrate Integrated Waveguide structure with the good characteristic such as small size,low loss,easy integration and so on,the filter works at center frequency 3.5 GHz with only 1.4 d B insertion loss and return loss is less than-15 d B,the filter size is only 10 mm×7.4 mm.3?Based on semiconductor Ga As technology and for the application of 5G millimeter wave communication system,an integrated on chip bandpass filter is proposed with a CRLH structure.The interdigital capacitor and grounding inductor of the Left-Handed characteristics in the CRLH structures are studied and designed respectively,based on the coupling effect and parasitic effect,the transmission zero is formed and the stopband suppression is enhanced,the equivalent circuit and main structural parameters are analyzed,and the GSG PAD is optimized for testing and the matching problem caused by it is corrected.The operating frequency of the proposed filter covers 5G millimeter-wave frequency band(24.25GHz-27.5GHz),the insertion loss is only 1.9d B and the return loss is less than-25 d B,the filter size is only 0.62mm×0.51mm(including PAD).This thesis focuses on demand of 5G communication system,an on chip integrated bandpass filter which works at frequency band(24.25 GHz-27.5 GHz)is proposed,insertion loss of the filter is only 1.9d B and return loss is less than-25 d B,the size of the filter is only 0.62mm×0.51mm(including PAD).The proposed design greatly meets the trend of communications terminal miniaturization,highly integration and well-performing,it has important engineering scientific research value and practical significance in developing 5G communication technology.