Research On Key Technology For High-Performance And Miniaturized Substrate Integrated Waveguide Filtering Antenna

With development of the wireless communication technology,the wireless communication devices have the trend for low-cost,miniaturization and integration.RF front-end components,such as antennas and filters,also turn to be much more miniaturized and lightweight.On the one hand,antenna and filter are two indispensable components in radio frequency front-end circuit,which are usually designed independently and then cascaded with each other.But,by the cascaded arrangement,it would inevitably lead to an enlarged circuit size,and a degraded system performance on account of the extra insertion loss of the connection.The filtering antenna integrates the functions of antenna and filter into just a single device,so that it could not only possess the radiation performance of an antenna in the working frequency band,but also effectively suppress the radiation energy outside of the working frequency band.On the other hand,Substrate Integrated Waveguide(SIW)technology has the advantages of high quality factor,low loss,high power capacity and easy integration with planar circuits,so it holds a variety of applications in the design of antennas,filters and duplexers at present.Combining the advantages of SIW technology in integration design and the SIW structural superiority,filtering antennas based on SIW technology have received extensive attention.Under the application scenario of wireless communication platform with limited space,this dissertation focuses on high-performance and miniaturized filtering antenna which is based on SIW technology,and develops SIW linear polarization,circular polarization,duplex and dual-frequency filtering antennas to meet different applications.The main research contents of this dissertation are as follows:(1)Propose a design method of the linearly polarized SIW filtering antenna which is loaded with a single rectangular slot,and also develop the extraction method of relevant parameters.Based on the linear polarization SIW filtering antenna model loaded by a single rectangular slot,a SIW filtering antenna with right-hand circular polarization and left-hand circular polarization can be achieved by replacing a single rectangular slot by a pair of mutually perpendicular rectangular slots and introducing a pair of metal perturbation posts into the radiating cavity.The simulation results of right-handed and left-handed circular polarization have a good agreement,demonstrating that a-10 dB impedance bandwidth is 2.4%,and a axial ratio bandwidth is 0.5%.The maximum gain is 7.1 dBic in the working frequency band.Finally,a method of loading Complementary Slit Ring Resonator(CSRR)is proposed to expand the impedance bandwidth of the SIW filtering antenna.The experimental results show that the-10 dB impedance bandwidth of the antenna is 6.3%,the maximum gain is 6.73dBi,and the overall volume is 0.0115?₀³.(2)Develop a design approach of high-performance miniaturized half-mode SIW filtering antenna by loading a parasitic patch.Utilizing the advantages of half-mode substrate integrated waveguide(HMSIW)technology in terms of miniaturization,a high-performance miniaturized linear polarization HMSIW filtering antenna with two radiation nulls was successfully realized by loading the metal short-circuited posts to further improve the out-of-band selectivity,after combing the HMSIW structure and parasitic patch to construct a topology with multi-path coupling.The measured results exhibit that the filtering antenna possesses a profile of 0.015?₀,an overall volume of0.005?₀³,a-10 dB impedance bandwidth of 5.1%,an in-band maximum gain of 6.3dBi,and a suppression level of more than 15dB within stopband.Based on the design of linearly polarized HMSIW filtering antenna,the right-handed and left-handed circularly polarized HMSIW filtering antennas are realized by truncating the corner of the parasitic patch.In the two circularly polarized states,the filtering antennas possess-10dB impedance bandwidths of 6.9%,the axial ratio bandwidths of 0.8%,and the maximum gains of 7.1 dBic.(3)Develop the design method of miniaturized SIW dual-frequency filtering antenna and duplex filtering antenna by employing dual-mode SIW cavity cooperated with HMSIW radiator.On the one hand,a miniaturized SIW dual-frequency filtering antenna can be achieved by combining the SIW dual-mode cavity operating at the fundamental mode and high-order mode with the HMSIW radiator.The measured results show that the antenna possesses a profile of 0.02?₀,a transverse size of 0.4?₀².The-10 dB impedance bandwidth in low-frequency and high-frequency passbands are2.1%and 4.1%,and the maximum realized gains are 4.9 dBi and 5.38 dBi,respectively.On the other hand,according to the characteristics of the electric field distribution of the two orthogonal modes in the SIW cavity,the feeding cavity could be shared by designing the feeding position of the two ports and the coupling position of the metal coupling posts,and thus the port isolation between them could be realized.Then after combining the SIW cavity operating at the orthogonal modes with the HMSIW radiator,the design of the high-performance miniaturized SIW duplex filtering antenna is realized by using the principle of filter synthesis design.The measured results show that the-10 dB impedance bandwidths of the antenna in the low-frequency and high-frequency channels are 3.2%and 3.9%,respectively,and the maximum in-band gains are 4.36 dBi and 4.83 dBi,respectively.The antenna gain curves exhibit good frequency selectivity and out-of-band suppression characteristics.The port isolation of the low-frequency channel is greater than 25 dB,and the high-frequency channel is greater than 23 dB.