Research On Miniaturized Substrate Integrated Waveguide Filter And Its Application In 5G Communication System

With the rapid development of wireless communication technology,4G LTE technology is widely spread in people’s daily life.However,with the continuous growth of mobile data demand and the rapid development of multimedia technology,the traditional mobile communication system has become increasingly unable to meet the requirements of people for higher transmission rates,larger number of user connections and lower delay.At present,in order to meet the demands for better user experience and social development,5G communication technology has become a research hotspot and attracted great attention from all over the world.Compared with the previous generation of mobile communication technology,5G communication technology requires higher data transmission rate,higher frequency utilization,lower air delay and larger system capacity and connection number.In this paper,miniaturized substrate integrated waveguide(SIW)filters,such as 1/4mode,1/8 mode and 1/16 mode SIW filters,are studied and applied to the development of RF transceiver front-end of highly-integrated multifunctional devices,low phase noise oscillators and 5G communication systems.The key modules can be applied in the system to achieve good performance.The main contents and innovations of this paper are summarized as follows:(1)A series of eighth mode substrate integrated waveguide(EMSIW)bandpass filters are proposed.Based on the systematic analysis of the electromagnetic characteristics,feeding types and quality factor of EMSIW resonators,a variety of structures of EMSIW bandpass filters are developed by using two-order electric coupling and two-order magnetic coupling,which can generate various frequency response characteristics with transmission zeros out of band.Compared with the traditional SIW filter,the size of the filter is reduced by 87.5%.In order to expand the higher-order EMSIW filter,based on the two-order magnetic coupled bandpass filter,the three-order EMSIW bandpass filter with CPW loading technology is developed by etching the coplanar waveguide(CPW)structure on the two cavity surface.An additional transmission pole and a transmission zero are generated,which improves selectivity and broadens the bandwidth.Combined with the source-load coupling technology,EMSIW and quarter mode substrate integrated waveguide(QMSIW)substrate is developed to design a hybrid bandpass filter.The hybrid bandpass filter designed by EMSIW and QMSIW combination not only reduces the circuit size,but also generates multiple transmission zeros outside the passband.Combined with multi-layered PCB technology,the four-order compact EMSIW bandpass filters are developed,which have Chebyshev response and Quasi-elliptic function response,respectively.Compared with the traditional SIW filter,the size of the filter is reduced by 93.75%.The research can be applied to the circuit design of miniaturization and high integration of microwave communication system front-end module.The results of this chapter have been published in the international core journal IEEE Transaction on Microwave Theory and Technology and the international conference Proceeding of 2019 International Wireless Symposium(IWS).(2)Quarter mode substrate integrated waveguide(QMSIW)circular cavity bandpass filters with metallized single/dual via-holes and surface etched slotlines perturbation are proposed.Loading a metallized via-hole near the center of the QMSIW circular cavity can perturb the resonant frequency of the fundamental mode(TM10/TM01)to two high modes(TM20/TM02,TM12/TM21)resonant frequencies,and achieve the response of the triple mode QMSIW bandpass filter.Loading another metallized via-hole near the arc of the cavity will perturb the higher spurious mode frequency to a higher stopband.On the surface of the traditional QMSIW circular cavity,the "C" shaped/ "E" shaped slotlines are etched to achieve the response of the triple mode QMSIW bandpass filters.The "C" shaped slotline can provide an additional transmission zero and a transmission pole near the higher mode frequencies,while the "E" shaped slotline can generate two transmission zeros and one transmission pole additionally near the higher mode frequencies.On this basis,the QMSIW filtering power divider with metallized double via-holes perturbation and QMSIW bandpass filter with "E" shaped slotline by single metallized via-hole perturbation are developed.The research results of this chapter have been published in the international core journal of Electronics Letters and International Journal of RF and Microwave Computer-aided Engineering.(3)The SIW filtering power divider with shielding structure is proposed,which improves the quality factor of SIW cavity,reduces the radiation loss,and exhibits expansibility.Combined with the analysis of the shielding SIW resonator mode structure,a series of shielding pure HMSIW,pure QMSIW and HMSIW/QMSIW hybrid filtering power dividers are designed to realize the miniaturization and multi-function characteristics.In addition,the in-phase and out-of-phase filtering power dividers based on QMSIW are proposed.The in-phase filtering power divider adopts a single-layered circuit structure,and realizes the two-order filtering power divider by using the angle feeding input and side feeding output.The out-of-phase filtering power divider adopts a double-layered circuit structure,and realizes 180 deg phase difference through the top-side and bottom-side feeding output.The filtering characteristic is realized through the angle feeding input and output.The filtering power divider can be applied to the miniaturization and highly-integrated circuit design of the transceiver front-end module in the microwave communication system.The research results of this chapter have been published in the international core journal of IEEE Access and international conference Proceeding of 2018 International Wireless Symposium(IWS).(4)A sixteenth mode substrate integrated waveguide(SMSIW)feedback oscillator is proposed.The four-order quasi-elliptic function filter is developed by using the SMSIW resonator combined with the multilayered circuit board integration process.It acts as a resonant loop of the feedback oscillator,and produces two transmission zeros at both sides of the passband,which is beneficial to improving the group delay characteristics near the resonant frequency.The size of SMSIW resonator is 96.875% smaller than that of traditional SIW resonator.In addition,an X-band push-push oscillator with parallel feedback configuration is proposed.The balanced bandpass filter is utilized as the resonant unit of the oscillator.Its differential mode response and common mode response can strengthen the even mode signal and suppress the odd mode signal,respectively.The proposed parallel feedback push-push oscillator not only widens the frequency range of the oscillator,but also reduces the design difficulty and complexity of the sub-circuits,it can obtain good phase noise performance.The research results of this chapter have been published in the international core journal of IEEE Transactions on Components,Packaging and Manufacturing Technology and International Journal of RF and Microwave Computer-aided Engineering.(5)A K-band feedback parallel oscillator with dual-mode air-filled substrate integrated waveguide(AFSIW)resonator is proposed.The AFSIW dual-mode resonator removes the dielectric-filled substrate in the resonant cavity,and the upper and lower surfaces are pressed by silver-plated metal structures to form the AFSIW cavity structure,obtaining higher quality factor and lower loss,improving the phase noise performance of the feedback oscillator.Based on the AFSIW technology,a 38-39 GHz broadband high-efficiency transmitter is developed.Two order and four order AFSIW dual-mode bandpass filters are designed to enhance the suppression of local oscillator leakage and other spurious frequency signals,reduce the loss in the transmission link.At the same time,combining envelope tracking(ET)and digital predistortion(DPD)technology,the efficiency and linearity of the transmitter are well improved.The research results of this chapter have been published in the international conference 2019 Asia-Pacific Microwave Conference(APMC)and submitted to the international core journal of IEEE Access.