Wide-angle Scanning Planar Phased Array Antenna Based On SIW Technology

The beam scanning of phased array antennas is realized by controlling the input phase fed into each port.Compared with the traditional mechanical scanning array antennas,the phased array antennas have the advantages of fast scanning speed and high scanning accuracy.The planar phased array antennas have been widely used to the communication and radar systems because of their features of low cost,easy integration,and light weight,etc.However,the scanning range of planar phased array antennas is limited because of the limited beamwidth of planar antennas.Multiple sub arrays are generally required to expand the scanning range.The main goal of this dissertation is to improve the beam scanning range of planar phased array antennas by simply broadening the beamwidth of the planar antenna element.The geometric structures of microstrip antennas can be easily managed with the assistance of substrate-integrated waveguide(SIW)technology to obtain the desired wide beamwidth.Then,the surface wave mode is involved to enhance the radiation performance at the direction along the ground plane of planar phased array antennas.The main research contents of this dissertation are summarized as follows:First,the research background of this dissertation is presented.A novel magnetic dipole is proposed,and then applied to wide-angle scanning planar phased array antenna.By placing two rows of metallized via holes at the radiation slots of patch antenna by using the SIW technology,and etching a slot at the center of patch,one can obtain a single magnetic dipole adjacently placed above the ground plane.The equivalent magnetic dipole is featured by the wide beamwidth in its E-plane,which then can be applied to the wide-angle scanning planar phased array antenna.A low-profile printed dipole antenna is presented and studied,then applied to wide-angle scanning planar phased array antenna.Using the SIW technology,the two open ends of traditional printed dipole antenna are shorted by metallized via holes to obtain an equivalent E-plane point source,which shows the wide beamwidth in its E-plane.The modified printed dipole antenna is suitable for the construction of E-plane wide-angle scanning phased array antenna.A low-profile electromagnetic dipole antenna based on the SIW technology is proposed.The proposed electromagnetic dipole antenna has symmetrical radiation pattern in the E-and H-plane.In addition,the proposed antenna shows the desired performance of wide beamwidth.In chapter 2,a magnetic dipole with wide beamwidth in the E-plane is presented.However,the level of cross polarization is high in the H-plane.To reduce the cross polarization and optimize the radiation pattern,an electromagnetic dipole antenna is proposed by rearranging the metallized via holes and reassigning the feeding structure.Both the E-and H-plane planar phased array antennas based on the proposed electromagnetic dipole show the desired performance of wide-angle scanning and low cross polarization.Two SIW cavity-backed patch antennas are proposed and used to construct H-plane wide-angle scanning planar phased array antennas.The SIW technology is used to control the propagation of surface wave mode in the grounded dielectric substrate to obtain the desired stable scanning performance.The diffraction of the surface wave at the truncation of the grounded dielectric substrate is used to improve the gain of the planar patch array antennas at the low elevation angles within a wide bandwidth.To expand the scanning range of the H-plane planar phased array,the thickness of the substrate should be increased to support the TE₁ mode.Then the SIW technology is used to suppress the TM₀mode without influencing the TE₁ mode.A cylindrical SIW cavity-backed slot antenna is presented.The odd TM₀₁₀,TM₁₁₀and TE₁₁₁ modes of the cylindrical SIW cavity are involved to achieve the desired wideband performance.Compared to the rectangular cavity,the cylindrical cavity is more preferable while used to achieve the multi-resonance based wideband antenna because of its mode diversity.Gaps are deployed at the cavity wall to narrow the frequency interval between involved resonant modes,thereby obtain a better impedance matching within a wide bandwidth.Compared to other wideband antennas based on multi-resonance,the proposed antenna has a more compact size,which shows a great potential to construct two-dimensional wideband wide-angle scanning phased array antennas.Finally,the research contents of this dissertation are summarized and future works are presented.